Virtual Lecture Series on Nanodiamond

Monthly Lectures

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We are proud to announce a program of lectures on cutting-edge nanodiamond and “quantum” macroscale diamond research.

Please note that Adamas Nanotechnologies, Inc. is not longer using Zoom to support our Virtual Lectures. We now use Microsoft Teams and participants will need to register for free in order to join.

Webinar Registration

Dr. Nicholas Nunn, Adamas Nanotechnologies

“Quantitative Detection of Molecular Oxygen in the Gas Phase with Fluorescent Nanodiamonds”

September 24, 2026 - 11:00 AM EDT, 3:00 PM UTC

Abstract: Monitoring oxygen is essential in life sciences and industrial applications.  Quantitative detection of paramagnetic molecular oxygen (O2) is demonstrated at atmospheric pressure and elevated pressure using oxygen gas mixtures balanced with nitrogen using optically detected magnetic resonance (ODMR) from negatively charged nitrogen-vacancy (NV⁻) centers in fluorescent nanodiamonds (ca. 70 nm).  Continuous-wave (CW) ODMR contrast is measured using a double-modulation (lock-in) detection scheme applied to both optical excitation and microwave drives. The ODMR contrast decreases linearly with oxygen partial pressure, with a sensitivity coefficient k of (-10.1 x ± 0.3) x 10⁻⁴ % mmHg⁻¹. The oxygen detection limit of the experimental setup was estimated to be approximately 8 mmHg O2 partial pressure (corresponding to about 1% O₂ in the gas mixture). Cycling of the content of O₂ in the gas mixture in the range of 0-5 % revealed a slight hysteresis and corresponding repeatability of 0.006 in percent ODMR contrast. The applicability of the nanodiamond-based oxygen quantum sensor was further demonstrated by detecting transient bursts of molecular oxygen generated by enzyme-catalyzed decomposition of hydrogen peroxide. 

 

Upcoming Lectures

  • October 29th

    Dr. Mary De Feudis
    Institut de Recherche de Chimie Paris

    “From Materials to Quantum Sensing: Engineering Color Centers in Nanodiamonds”

  • November 19th

    Bradley Flinn
    University of Nottingham

    "Probing Physicochemical Transformations at the Nanoscale Using Nanodiamond Quantum Sensors"

  • TBD

    Please reach out to us if you’re interested in giving a lecture in Fall 2026!

2026

  • Dr. Arsene Chemin - “Engineering Diamond Surfaces for Quantum and Catalytic Applications thanks to Synchrotron Characterization.”

    Diamond is an unconventional semiconductor with a wide bandgap and a remarkable ability to host defects and intrabandgap states, enabling applications in quantum technologies with NV centers as well as catalysis using B and N doping. Unlike most semiconductors, diamond surfaces do not form a native oxide layer but are instead terminated by surface atoms and molecular groups (sp² reconstructions, –OH, =O, –H, –N, –F, etc.). These terminations introduce localized states within the bandgap, strongly modify surface electron affinity and band bending, can be photoexcited, lead to charge separation and trapping [2], and evolve depending on the environment and usage. Understanding and controlling these effects is essential for designing the diamond-based applications of tomorrow.

    In this talk, I will show how different diamond surface terminations control electronic structure and interfacial charge-transfer processes, and how these properties change under operating conditions. Using state-of-the-art synchrotron X-ray spectroscopies (NEXAFS, depth-resolved XPS, in situ XAS) [1] combined with laboratory experiments [2,3,7], we probe a variety of diamond interfaces. From this understanding, I will illustrate how nitrogen-terminated diamonds [3–5] stabilize the NV⁻ charge state compared to oxidized surfaces [6], and how functionalized nanodiamonds and B- and N-doped diamonds can be engineered for electro- and photoelectrochemical applications, including CO₂ reduction [7,8].

    References

    1. Petit, T., Lounasvuori, M., Chemin, A., & Bärmann, P. (2023). Nanointerfaces: concepts and strategies for optical and X-ray spectroscopic characterization. ACS Physical Chemistry Au, 3(3), 263–278.

    2. Chemin, A., Levine, I., Rusu, M., Vaujour, R., Knittel, P., Reinke, P., ... & Petit, T. (2023). Surface‐Mediated Charge Transfer of Photogenerated Carriers in Diamond. Small Methods, 7(11), 2300423.

    3. Chemin, A., Kuntumalla, M. K., Brzhezinskaya, M., Petit, T., & Hoffman, A. (2024). Depth profiling of microwave nitrogen-terminated polycrystalline diamond surfaces by energy-dependent X-ray photoelectron spectroscopy. Applied Surface Science, 661, 160082.

    4. Kuntumalla, M. K., Chemin, A., Finas, M., Girard, H. A., Michaelson, S., Petit, T., ... & Hoffman, A. (2024). Nitrogen-terminated milled nanodiamond surfaces by plasma exposure. The Journal of Physical Chemistry C, 128(37), 15573–15582.

    5. Kuntumalla, M. K., Chemin, A., Doron, N. M., Brzhezinskaya, M., Petit, T., & Hoffman, A. (2025). Impact of acid etching on surfaces and near-surface region in nitrogen plasma terminated polycrystalline diamond. Diamond and Related Materials, 158, 112623.

    6. Malkinson, R., Kuntumalla, M. K., Chemin, A., Petit, T., Hoffman, A., & Bar-Gill, N. (2024). Enhanced quantum properties of shallow diamond atomic defects through nitrogen surface termination. Journal of Materials Chemistry C, 12(20), 7206–7213.

    7. Chemin, A., Godeffroy, L., Rusu, M., Drisch, M., Finze, M., Knittel, P., ... & Petit, T. (2025). Modulating Surface Redox Reactions and Solvated Electron Emission on Boron-Doped Diamond by (Photo)electrochemistry. PRX Energy, 4(3), 033011.

    8. B. Kiendl, A. Chemin, A. H. Day, et al. “ Intrabandgap States Engineering in Functionalized Nanodiamond to Generate Solvated Electrons for Photocatalysis Under Solar Illumination.” Advanced Functional Materials (2026): e23545. https://doi.org/10.1002/adfm.202523545

    Jean-Charles Arnault and Hugues Girard - “Nanodiamonds for photocatalysis”

    Among nanoscale semiconductors, nanodiamonds (NDs) have only recently begun to be seriously considered for photocatalytic reactions, due to confusion with the ideal monocrystalline diamond, characterized by a wide bandgap (5.5 eV) requiring deep UV illumination (230 nm) to trigger its photoreactivity. At the nanometric scale, NDs carry native defects (sp2 carbon, chemical impurities such as nitrogen) as well as an enhanced surface-to-volume ratio. These features introduce electronic states within the band gap, lowering the light energy required to initiate charge separation and promoting photocatalytic reactions at their interface. In this lecture, we will detail the studies we have conducted in recent years, which explore the colloidal and electronic properties of nanodiamonds suspended in water [1-3] and their photoactivity, from charge carrier generation within the nanoparticles to photocatalytic reactions of interest, such as hydrogen production [4] and the complete mineralization of polyfluoroalkyl substances (PFAS) [5]. We will demonstrate how the nature and surface chemistry of nanodiamonds fundamentally drive their photoreactivity and photocatalytic applications, enabling diverse interfacial chemical reactions.

    [1] Saoudi et al., Carbon (2023) https://doi.org/10.1016/j.carbon.2022.10.084

    [2] Njel et al., Carbon (2024) https://doi.org/10.1016/j.carbon.2024.119668

    [3] Girard et al., Nanoscale (2025) https://doi.org/10.1039/D5NR02241J

    [4] Marchal et al., Adv. Energy Sustainability Res. (2024) 

    https://doi.org/10.1002/aesr.202300260

    [5] Jimenez et al., ChemXxiv (2025) 10.26434/chemrxiv-2025-zp563

2025

  • Ben Miller and Felix Donaldson - “Widefield diagnostics and sensing with nanodiamonds”

    Quantum sensors leverage quantum mechanical effects to probe their external environment. Nitrogen-vacancy (NV) centres in diamond are optically addressable single spins that are sensitive to magnetic noise, charge, electromagnetic fields, temperature [1], and pressure, promising impactful sensing methods for biophysics [2,3] and diagnostics [4]. Crucially, NV centres can be hosted in functionalised nanodiamonds, enabling targeted measurements in complex biological samples. Conventional bulk and single-nanodiamond NV protocols use a DC bias field aligned with the NV axis and a transverse microwave field to split the ms = ±1 levels, minimising inhomogeneous broadening and enabling high-fidelity quantum control, but bulk platforms limit biomarker proximity and surface chemistry, while single-particle methods require tracking and suffer from low photon counts. We instead use ensembles of randomly oriented nanodiamonds at zero bias field in a non-imaging widefield geometry, allowing selective functionalisation and high signal levels at the expense of reduced control fidelity and increased NV inhomogeneity. We present two applications: (i) translation of our previous work on low-cost diagnostics [5], with an assay to detect SARS-CoV-2 antigen [6]. In a blinded clinical study we achieved 95.1% sensitivity (Ct ≤ 30) and 100% specificity versus RT-qPCR, with no cross-reactivity to influenza A, RSV or rhinovirus and an estimated ~2-day earlier detection than gold nanoparticle LFTs; and (ii) arbitrary-field sensing and zero-field double electron–electron resonance with randomly oriented nanodiamonds, towards radical spectroscopy of external spins.

    1. Doherty, M. W. et al. The nitrogen-vacancy colour centre in diamond. Phys. Rep. 528, 1–45 (2013).

    2. Belser, S., Hart, J., Gu, Q., Shanahan, L. & Knowles, H. S. Opportunities for diamond quantum metrology in biological systems. Appl. Phys. Lett. 123, 020501 (2023).

    3. Aslam, N. et al. Quantum sensors for biomedical applications. Nat. Rev. Phys. 5, 157–169 (2023).

    4. Zhang, T. et al. Toward Quantitative Bio-sensing with Nitrogen–Vacancy Center in Diamond. ACS Sens. 6, 2077–2107 (2021).

    5. Miller, B. S. et al. Spin-enhanced nanodiamond biosensing for ultrasensitive diagnostics. Nature 587, 588–593 (2020).

    6. DeCruz, A. T. et al. Quantum-enhanced nanodiamond rapid test advances early SARS-CoV-2 antigen detection in clinical diagnostics. medRxiv https://doi.org/10.1101/2025.329920 (2025) doi:10.1101/2025.329920.

    Prof. Dr. Joerg Wrachtrup - “Multiparameter quantum sensing with nanoscale”

    Spin defects in wide band gap semiconductors enable quantum sensing with a spatial accuracy of a few nano meter. This leads to a variety of intriguing applications in material- as well as bio science. It turns out, that the sensor spin is sensitive to a number of external parameters and that dedicated Hamiltonian engineering renders the system sensitive to a particular quantity, like e.g. temperature while it stays insensitive to others, like e.g. magnetic fields. The talk will demonstrate sensing of various quantities and discuss the enhancement of sensor performance by using ancilla quantum bits for signal processing.

    Dr. Fabrizio Moro - "Methods for detection of magnetic field polarity with NV centers in diamond"

    Diamond-based magnetometry relies on Optically Detected Magnetic Resonance (ODMR) of negatively charged NV centers where changes of photoluminescence are monitored under magnetic resonance condition. Although, from the ODMR spectra is possible to reconstruct the magnetic field vector, they are inherently independent on the magnetic field polarity which is a key property for applications such as reading of magnetic bits in Hard Disk Devices (HDD) as well as for the understanding of phenomena in nanomagnetism such as domain walls, magnetic vortexes and skyrmions.[1] This limitation is commonly circumvented by monitoring the photoluminescence shift induced by the sample’s local field of a resonance signal singled out by a bias field. Recently we demonstrated a new method based on lock-in detection of ODMR spectra recorded by demodulation of a small oscillating applied magnetic field.[2] The phase-locking between the magnetic field and the photoluminescence signal enables to establish a direct and unambiguous correlation between the symmetries of the resonance lines and the sign of the magnetic field polarities. With this presentation the methods for detection of the magnetic field polarity will be presented along with some applications in condensed matters physics. Furthermore, the sensitivities and advantages of the modulation field detection method will be discussed.

    Dr. Birol Ozturk - “Advances in NV-Diamond Quantum Sensing: From Handheld Magnetometers to Nanodiamond-Based Magnetic Field Imaging”

    Quantum sensing using nitrogen-vacancy (NV) centers in diamond enables the detection of ultra-small changes in temperature, strain, and electromagnetic fields. While opportunities remain for improving sensitivity and expanding applications, particularly in quantum computing, the use of NV centers in bulk diamond for sensing is a relatively mature technology, with several commercial products already on the market. We have developed a battery-operated, handheld compact quantum sensor (CQS) based on bulk NV diamond for magnetic field detection. This device was optimized using machine learning algorithms to enhance performance. In this presentation, we will share our results on the development and characterization of the CQS magnetometer. Moreover, nanodiamonds offer additional advantages for quantum sensing due to their nanoscale size and flexibility. We have demonstrated a cost-effective magnetic sensing probe by depositing nanodiamonds on the tip of a glass micropipette. This novel probe operates as a scanning magnetic field imager, and we will present our results on its ability to capture magnetic field distributions from a non-uniform sample. Although action potential detection using NV centers in bulk diamond has been shown in cardiac tissue and whole organisms, subcellular-level recordings using nanodiamonds have yet to be achieved. We will also present our preliminary findings on the feasibility of detecting external magnetic fields using nanodiamonds internalized by mouse brain cells, paving the way for future cellular-level neuroimaging applications.

    Dr. Peter Knittel - “Tailored Diamond Films for Quantum Technologies by CVD growth”

    Diamond is a promising material for a wide range of quantum applications due its exceptional properties and color centers like the nitrogen vacancy (NV) center. In its negative charge state, the NV can act as a sensor to detect minute magnetic fields including oscillation magnetic fields encountered e.g., in nuclear magnetic resonance (NMR) spectroscopy.¹ In addition, the NV center and other color centers like SiV, GeV, SnV are promising candidates for qubits in quantum computing. For this, they should be accurately positioned in diamond films, e.g., on mesa structures,² or even within complex sandwich structures, e.g., containing isotopically enriched films.³

    We utilize a unique reactor design that allows for highly controllable process conditions by enabling the transfer of samples into the equilibrated plasma. Thus, etching of the sample during plasma start up is avoided, contaminations originating from sample exchange can be prevented, and sharp layer transitions between doped and isotopically controlled diamond films can be obtained. Besides the sample transfer, the growth temperature can be maintained also during standby time through a substrate heater, and a clean reactor environment is realized by a load-lock sample exchange system that allows for pre-treatments in vacuum before loading.

    Using this system, we demonstrate overgrowth of nanoscopic pillar structures yielding highly controlled tip geometries, and overgrowth of diamond waveguides structures obtained from Faraday cage angled etching.⁴ In addition, the growth of nanoscopic sandwich structures with isotopically enriched layers as well as delta doped N(V) layers will be shown on (100) and (111)-oriented diamond. Further prospects for precise positioning of color centers by growth will be discussed.⁵

    1. F. Bruckmaier, et al. Sci. Adv. 9 (2023). 2. A. Götze, et al. Phys. Status Solidi RRL 16 (2021), 2100373. 3. P. Schätzle, et al., Phys. Status Solidi A 220 (2023), 2200351. 4. C. Giese, et al. MRS Adv. 5 (2020), 1899. 5. N. Lang, et al. Phys. Scr. 99 (2024), 105408.

    Adrisha Sarkar - “High-precision chemical quantum sensing in flowing monodisperse microdroplets”

    A novel method integrating quantum sensing with droplet microfluidics is presented for high-precision chemical detection. Nanodiamonds with nitrogen-vacancy centers serve as quantum sensors to analyze rapidly flowing microdroplets containing analytes. This approach enables a noise-suppressed mode of optically detected magnetic resonance, allowing the detection of analyte-induced signals via nanodiamond fluorescence.

    The method demonstrates a low limit-of-detection for paramagnetic ions in droplets using small analyte volumes, with exceptional measurement stability. Additionally, droplets act as microconfinement chambers, enabling co-encapsulation of quantum sensors with various analytes, including single cells. This work paves the way for significant advancements, such as portable chemical testing devices, amplification-free chemical assays, and chemical imaging tools for probing reactions within microenvironments.

    Dr. Carlos Meriles - “Examining the dynamics of confined fluids using near-surface color centers in diamonds“

    Nanoscale confinement of liquids is central to a range of problems in chemistry, biology, and chemical engineering as it can result in enhanced viscosity, local fluidic order, or collective motion. Studying these effects, however, is notoriously difficult, mainly due to the lack of experimental methods with the required sensitivity and spatial or time resolution. Here we leverage shallow nitrogen-vacancy (NV) centers in diamond to probe the dynamics of room-temperature water molecules entrapped within ~5-nm-tall channels formed between the diamond crystal and a suspended hexagonal boron nitride (hBN) flake. NV-enabled nuclear magnetic resonance measurements of confined water protons reveal a much reduced H2O self-diffusivity, orders of magnitude lower than in bulk water. We posit the slow dynamics stem from the accumulation of photogenerated carriers at the interface and trapped fluid, a notion we support with the help of molecular dynamics modeling. Our results expose the importance of space charge fields in theories describing interfacial water, and lay out a route for investigating other fluids under confinement.

2024

  • Dr. Brian Blankenship - “3D Optically Detected Magnetic Resonance in Architected Micro-volumes”

    Optically addressable electron spins, such as nitrogen-vacancy (NV) centers in diamond, have emerged as powerful quantum sensors capable of remotely measuring a diverse array of physical parameters—including magnetic and electric fields, temperature, pressure, and rotation—with resolutions approaching the diffraction limit of light. Nanodiamonds, which host these NV centers, offer a minimal form factor that facilitates deployment in challenging scenarios where conventional sensors are impractical.

    In this talk, we present our work on leveraging the unique advantages of nanodiamonds in conjunction with two-photon polymerization to fabricate ultra-customizable, 3D-printable microstructures. This innovative combination enables the creation of designer material systems with precise control over their geometry and functionality at the microscale. Not only do we demonstrate the successful fabrication of these complex microarchitectures but also the spatial and transient measurements of Optically Detected Magnetic Resonance (ODMR) in three dimensions with sub-micrometer resolution inside complexly structured porous geometries. These techniques are simple to replicate results and have profound implications for the design of next-generation sensors and quantum devices.

    Dr. Quan Li - “Diamond based nanothermometry: opportunities and challenges”

    Temperature monitoring plays a crucial role in a wide range of processes, spanning from chemistry to life sciences. In recent years, the issue of spatial temperature non-uniformity has gained significant attention in various studies, yet limited information is available due to a lack of effective tools. The unique optical and spin properties of Nitrogen-vacancy (NV) electrons, combined with the high thermal conductivity and chemical inertness of the diamond host, make NV-containing nanodiamonds an exciting opportunity for in-operando thermometry with nanoscale spatial resolution. NV-based thermal sensing offers several features that make it highly promising for in operando nanothermometry applications. These include high spatial resolution, high sensitivity, a wide working temperature range, and compatibility with various working environments. In this presentation, we will showcase examples of spatially resolved temperature evolution, monitored by NV-based thermal sensing, in working electrochemical devices such as battery-like devices or electrolytic cells. By employing nanodiamond (ND) sensors, we have gained new insights into the corresponding electrochemical processes. Furthermore, we will address the challenges associated with ND-based thermal sensing and discuss potential solutions. This work has been carried out in collaboration with Renbao Liu, Gangqin Liu, Wenghang Leong, Ning Wang, Chufeng Liu, Ruqiang Dou, Zan Li, and Ying Wang. We acknowledge support from Croucher Senior Fellowship (SRF23401), CRF of RGC (Project No. CRF C4004-23G); and TRS of RGC (Project No. T45-406/23-R).

    Dr. Fernando Meneses - “Quantum Diamond Magnetometry and Machine Learning Applied to  Real-Time Object Monitoring”

    Remote magnetic sensing can be used to monitor the position of objects in real-time, enabling ground transport monitoring, underground infrastructure mapping and hazardous detection. However, magnetic signals are usually weak, complex and buried within a noisy environment, where no suitable physical magnetic models are available. In this work, we propose a Machine Learning (ML) method trained solely on experimental data measured by a quantum diamond magnetometer to monitor the position of a magnetic target in real-time, featuring complex magnetic signals below 1 uT. Our neural network, featuring both convolutional and dense layers, is trained on full-vectorial magnetic measurements and predicts the target's position at a 10 Hz rate, achieving 80% accuracy for a positional error of 43 cm. Our results open up the possibility to apply this ML method more generally for real-time monitoring of magnetic objects which will broaden the scope of magnetic anomaly detection applications.

    Dr Helena Knowles - “Multimodal Quantum Metrology in Living Systems Using Nitrogen-Vacancy Centres in Diamond Nanocrystals”

    Next-generation biological sensors and diagnostic tools require high sensitivity and spatial resolution to be able to identify emergent biological behaviour. Correlating multiple interdependent parameters at the nanoscale could help uncover details of cellular response to external perturbations. Temperature and viscosity are key parameters of interest that relate to cellular energetics and metabolism, morphological changes, cell division and active transport. Cells respond to temperature through viscoadaptation, and a change in viscosity may in turn affect the local temperature profile. In this talk, I will present our latest results on nanoscale quantum sensing in living human cancer cells. We use a diamond nanocrystal quantum sensor containing nitrogen-vacancy colour centres to extract information about the nanoscale thermal environment, the thermal and stochastic forces acting on the nanodiamond, and the properties of its nanoscale viscoelastic environment. We will also discuss opportunities in diamond-based quantum sensing for biomedical applications.

    Dr. Abraham Wolcott - “Tuning a Quantum Nanoprobe: Advancements in Diamond Chemistry using Halogens, Low-Z precursors and Metal Oxides”

    Quantum sensing and quantum communication technologies are emergent fields and will transform detection and cyber security in the 21st century. Nitrogen vacancy centers or NV centers are fluorescent defects hosted in diamond and can be described as a quantum bit (qubit) capable of magnetometry, electrometry and thermometry. The field of diamond surface chemistry is ripe for exploration as quantum sensing and quantum communication become mature with diamond and other exotic materials that host atomic defects. High-pressure high-temperature (HPHT) nanodiamond (ND) is the most common nanoscale host of NV centers and are typically purified with aerobic oxidation to form an oxygen rich surface. Past work has determined the surface to be largely terminated with alcohols similar to 111-terminated bulk diamond. In this work, a combination of halogen, low-Z and metal oxide chemistry on ND will be discussed. The chemical analysis is completed with overlapping laboratory and X-ray synchrotron-based spectroscopies. Chemical modalities using bromine, boron, nitrogen and silanes will be summarized and the results will be impactful for researchers using ultra-hard materials for quantum sensing applications and interested in controlling the surface properties including surface dipole moment and electronic noise.

    Fedor Jelezko - “Perspectives in Quantum Diamond Technologies”

    Optically active spin qubits in diamond have recently emerged as a candidate for a number of quantum technology areas, including quantum information processing and quantum sensing. The electron spin of the nitrogen-vacancy (NV) center can be optically polarized and readout. In addition, the electron spin of the NV center has a long coherence time under ambient conditions. These unique optical and spin properties make the NV spin qubit a unique system for quantum sensing. In this talk, we will introduce the new and rapidly developing field of nanoscale quantum sensing based on NV centers in diamond and potential applications for molecular imaging in life sciences. We will also discuss applications of NV centers in diamond nanoparticles for polarization of nuclear spins and the application of diamond-based hyperpolarization markers in ultrasensitive MRI.

2023

  • Erin Grant - “Measuring T1 relaxation from FNDs in solution: methodology and motivation”

    Optically active spin qubits in diamond have recently emerged as a candidate for a number of quantum technology areas, including quantum information processing and quantum sensing. The electron spin of the nitrogen-vacancy (NV) center can be optically polarized and readout. In addition, the electron spin of the NV center has a long coherence time under ambient conditions. These unique optical and spin properties make the NV spin qubit a unique system for quantum sensing. In this talk, we will introduce the new and rapidly developing field of nanoscale quantum sensing based on NV centers in diamond and potential applications for molecular imaging in life sciences. We will also discuss applications of NV centers in diamond nanoparticles for polarization of nuclear spins and the application of diamond-based hyperpolarization markers in ultrasensitive MRI.

    Dr. Romana Schirhagl - “Diamond Based Quantum Sensing for Free Radical Detection in Medical Samples“

    Free radical generation plays a key role in many biological processes including cell signalling, immune responses or ageing. On the other hand an access in free radical production is usually associated with stress responses and pathological conditions. However, free radical generation is challenging to measure since they are small, occur in low concentrations and are short lived. I the last years we have established diamond-based quantum sensing as a tool to measure free radical generation at the nanoscale. More specifically, we use nanodiamonds containing ensembles of nitrogen vacancy centers and track their movement while they are moving through living cells. At the same we measure the magnetic noise by relaxometry. Since free electrons in radicals cause such a signal, this method allows us to measure the free radical generations in the immediate surrounding of the particles. In this presentation, I will give an update on our progress in this field and on bringing this technique to the medical field. More specifically, I will show how we can measure disease status as well as drug effectiveness in living cells.

    Dr. Nicholas Nunn - “Magnetic Resonance and Optical Studies of HPHT Synthesized Diamond Microparticles With Controlled Nitrogen Content“

    Diamond particles hosting nitrogen vacancy centers is a platform material for potential use in emerging nano and microscale sensing technologies. These envisioned quantum sensors are based on optical manipulation and readout of NV centers in response to external environmental stimuli (e.g., temperature, strain, magnetic fields). The important prerequisites for such measurement protocols are NV centers with suitable spin properties such as long coherence and relaxation times. While such properties are readily achieved for bulk diamond crystals of suitable quality, the properties of diamond particles are often severely degraded by the presence of paramagnetic defects such as electronic spins associated with other nitrogen defects (P1 centers). We demonstrate the growth of microparticulate diamond with good crystal quality and controlled nitrogen content in the range of ca. 5-50 atomic ppm is possible. A resultant improvement in NV coherence times by approximately 3-fold is observed using pulsed electron paramagnetic resonance (EPR) across the range of nitrogen concentration studied. These results may provide a foundation for the production of the next generation of fluorescent diamond particles, which thus far have relied exclusively on particulate diamond with nitrogen contents in the range of ca. 100 atomic ppm.

    Alexander I. Shames - “Is there substitutional nitrogen in nanodiamonds? Solving a puzzle by magnetic resonance“

    One of the most actual scientific and technological challenges associated with the use of nanodiamonds (NDs) consists in fabrication of NDs particles with sizes less than 100 nm carrying high density of triplet (S=1) nitrogen vacancy centers (NV–). Substitutional nitrogen atoms in neutral charge state with electron spin S=1/2 (N0/C/P1 centers) are among fundamental precursors of NV–. Electron paramagnetic resonance (EPR) provides unambiguous identification and quantification of P1. P1 EPR spectra in both mono- and poly-crystalline diamond samples are characterized by well-resolved hyperfine structure (HFS). On diminishing fluorescent diamond microcrystallites’ size, drastic changes in EPR spectra occur: significant decrease in the abundance of NV–; successive decrease in contribution of the initial HFS split P1 signal; increase in contribution of a broad singlet signal; appearance and consistent growth of new narrow singlet signal. EPR spectra of small NDs (both crushed microdiamonds and detonation nanodiamonds-DNDs) consists of two structureless Lorentzians. In contrast, increasing the average size of NDs from nanometers to micrometers by sintering of DNDs under pressure leads to restoration of typical P1 EPR signals with resolved HFS pattern. Surveying the entire set of experimental EPR data obtained on a huge variety of diamond particles from micro- to nanometer size-range, obvious questions arise: (i)What does really happen with paramagnetic substitutional nitrogen on nanonization? (ii)Does the nitrogen atom migrate and/or change its charge state? (iii)How many P1 centers do really exist in NDs and DNDs? Proper analysis and interpretation of magnetic resonance data, especially EPR ones, allow adequate answering all these questions. It was assumed that, upon crushing of diamond particles, density of P1 practically doesn’t change and all effects concerned with disappearance of P1 HFS pattern and appearance of intensive narrow singlet component, occur due to dipole-dipole and exchange interactions of P1 centers with surface paramagnetic defects formed upon nanonization.

    Dr. Peter Maurer - “Emerging Quantum Sensing Technologies: Interfacing coherent qubits with biological targets”

    Quantum metrology enables some of the world’s most sensitive measurements. When applied to biophysical systems, diamond-based quantum sensors have the potential to probe processes that cannot be accessed by conventional technologies. Examples of such processes range from cancer research to neuroscience to developmental biology. However, interfacing coherent qubit sensors with fragile biological target systems has remained an outstanding challenge that has severely limited applications. In this talk, I will discuss a novel approach that combines single-molecule biophysics technology with quantum engineering to interface intact biomolecules on a diamond quantum sensor without impacting qubit coherence and bio-functionality. In a second part, I will discuss our recent work on engineering highly coherent quantum sensors based on diamond nanocrystal. Such nanosensors can readily be taken up by cells and integrated into intact organisms. However, coherence in these nanocrystal sensors is limited by surface noise, which severely reduces the sensor’s sensitivity. In our work we developed a new approach to engineer spin coherence in core-shell nanostructures which leads to a 50-fold improvement in qubit sensitivity. Finally, potential future applications of quantum sensing to biophysical and diagnostics will be discussed. 

    Dr. Abdelghani Laraoui - “Probing Nanoscale Magnetic Phenomena Using Diamond Quantum Sensing Microscopy”

    Diamond quantum sensing microscopy based on nitrogen vacancy (NV) centers has become a versatile tool to detect magnetic fields with an unprecedented combination of spatial resolution and magnetic sensitivity, opening up new frontiers in biological and condensed physics matter research. In this talk I will present two examples of using NV magnetometry in both scanning probe microscopy (SPM) and wide-field microscopy (WFM) geometries to probe nanoscale magnetic phenomena in different materials.

    First, I will discuss NV-SPM measurements of antiferromagnetic (AFM) domains switching in Cr2O3 and B-Cr2O3 thin films and device structures. Cr2O3 is an archetypical AFM oxide that permits voltage-control of the Néel vector. In addition, boron doping increases Néel temperature from 307 K to 400 K and allows realizing voltage controlled Néel vector at zero applied magnetic field, a promising finding to AFM spintronics. NV measures the magnetization profile, which shows well-defined magnetized nano-domains, with typical domain sizes ∼40-300 nm in B- Cr2O3 and > 300 nm in undoped film respectively. I will show that these AFM domains can be controlled with nanostructuring, voltage, and temperature.

    Then I will discuss NV-WFM measurements on individual Fe(Htrz)2(trz)](BF4)] (Fe triazole) spin-crossover (SCO) nano-rods of size varying from 10 to 1000 nm. Fe triazole SCO complexes exhibit thermal switching between low spin (LS) and high spin (HS) states which are applicable in thermal sensors and molecular switches. While the bulk magnetic properties of these molecules are widely studied by bulk magnetometry techniques their properties at the individual level are missing. Scanning electron microscopy (SEM) and Raman spectroscopy are performed to find out the size of the nano-rods and to confirm the spin state (LS vs HS) of the Fe triazole molecule respectively. The stray magnetic fields produced by individual nano-rods are imaged by NV as a function of temperature (up to 150 0C) and applied magnetic field (up to 3500 G) and correlated with SEM and Raman. We found that most LS states are either paramagnetic or superparamagnetic in contrary to predictions of diamagnetic behavior.

2022

  • Dr. Ashok Ajoy - “Novel NMR Quantum Sensors via Hyperpolarized Nuclei“

    We report on new experiments that demonstrate the potential of hyperpolarized nuclear spins to serve as sensitive magnetometers and chemical sensors of their local environment. Our goals are to leverage this to create new forms of sub-micron-scale NMR detectors using hyperpolarized nanoparticles. We demonstrate this with 13C nuclei in diamond hyperpolarized through Nitrogen-Vacancy (NV) centers.

    The methodology leverages the exquisite spin lifetimes possible in diamond 13C nuclei under RF driving, wherein we observe lifetimes in excess of T2’=90s at room temperature. When exposed to a time-varying (AC) magnetic field, the nuclei undergo secondary precessions that carry an imprint of its frequency and amplitude. Hyperpolarization and continuous spin readout enable significant gains in sensitivity and resolution. Fourier-limited resolution is better than 100 mHz and single-shot sensitivity is better than 70pT at a bias field of 7T, amongst the best for quantum sensing at high-fields. Overall, this suggests interesting new opportunities for spin sensors possible via hyperpolarized, low-gamma, nuclei.

    Dr. Melissa Mather - “Imaging Cellular and Intracellular Components Using Quantum Diamond Microscopy“

    The Nitrogen Vacancy (NV) centre in diamond is becoming an increasingly investigated probe in biology owing to its excellent photoluminescence properties and low cytotoxicity profile. Indeed, the sensitivity of NV photoluminescence to external factors that perturb the NV spin and/or charge state is being exploited as a sensing scheme. Coupled with existing fluorescence microscopy techniques readily available in biological laboratories it is now possible to map and track critical cellular events such as free radical generation, electrical activity and iron uptake and release by metalloproteins. In this talk I will present details of NV sensing schemes deployed using a minimally modified commercial fluorescent microscope that could be readily deployed in biology labs by non-experts. I will also report example uses of this instrumentation imaging cellular and intracellular components in mammalian cells and mitochondrial extracts.

    Dr. Pauli Kehayias - “High-Resolution Quantum Diamond Magnetic Imaging for Applications in Condensed-matter Physics, Electrical Engineering, and Hardware Security”

    The quantum diamond microscope (QDM) is a technology used for magnetic imaging with high spatial resolution. Using a synthetic diamond sample with a surface layer of magnetically-sensitive NV centers to optically image the magnetic fields from external sources, a QDM offers micron-scale resolution over a few-mm field of view, high-reliability operation in ambient conditions, and high signal-to-noise readout of nano- and micro-scale magnetic sources. These attributes are enabling new scientific results that were previously impractical or impossible. In this talk I will present recent results applying NV magnetic microscopy to Sandia problems, including applications in electrical engineering, hardware security, condensed-matter physics, and quantum computing.

    Ryuji Igarashi - “Surface Chemical Modification of Fluorescent Nanodiamonds Opens New Possibilities for NV Centers in the Measurement of Living Systems”

    How to measure biological changes quantitatively occurring inside cells is a significant issue in biology, which has remained unresolved for many years. Cells, with only a few tens of micrometers, are pretty small for such measurements.  Moreover, each cell is further divided into smaller —micrometers to nanometers — compartments, each of which has its characteristic function, and the homeostasis of the cell system depends on the complex interactions among these small compartments. Therefore, to investigate intracellular systems quantitatively, novel technologies are a long-felt need for quantitative measurements of various parameters in the nanometer range. Recently, a fluorescent nanodiamond containing nitrogen-vacancy centers (NV centers) has attracted attention as a promising nanometer-scale measurement tool. An NV center is a lattice defect harboring a pair of triplet electrons, emitting 650-750 nm red fluorescence by photoexcitation with green light. The fluorescence intensity is known to be strictly conjugated with the spin state of the triplet electrons. Therefore,  fluorescent nanodiamonds can be used for nanometer-scale measurement via microscopic fluorescence detection. Indeed, this idea is highly compatible with fluorescent bioimaging techniques such as cellular imaging and biological imaging and is expected to be applied to various biological fields, including cell biology, neuroscience, immunology, and so on.  In this lecture, I would like to talk about how chemical modification of nanodiamond surfaces can extend the possibilities of microenvironment measurements of biological samples using nanodiamond NV centers. In particular, I’ll mention specific molecular and cellular measurements enabled by modifying nanodiamonds with hyperbranched polyglycerol and pH nanosensors realized by enriching a particular chemical group.

    Haksung Jung and Keir C. Neuman - “Development of Fluorescent Nanodiamonds for Latent Fingerprint Detection”

    Latent fingerprints (LFPs) are one of the most important forms of evidence in crime scenes due to the uniqueness and permanence of the friction ridges that comprise fingerprints. An efficient method to detect LFPs is therefore crucial in forensic science. However, traditional detection strategies are limited by low sensitivity, low contrast, high background, and complicated processing steps. Taking advantage of the remarkable optical and physical properties of fluorescent nanodiamonds (FNDs), we developed an approach that provides biocompatible, efficient, and low background latent fingerprint detection with polyvinylpyrrolidone (PVP) coated FNDs (FND@PVP). We demonstrate that PVP-coated FNDs are biocompatible at the cellular level, neither inhibiting proliferation nor eliciting an immune response.  We then show that PVP coating enhances the physical adhesion of FNDs, resulting in efficient binding to latent fingerprint ridges due to the intrinsic amphiphilicity of PVP. Clear, well-defined ridge structures with first, second, and third-level LFP details are revealed within minutes by FND@PVP. The combination of this binding specificity and the remarkable optical and physicochemical properties of FND@PVP permits the detection of LPFs with high contrast, efficiency, selectivity, sensitivity, and reduced background interference. Our results demonstrate that FND@PVP nanoparticles have great potential for high-resolution imaging of LFPs. 

    Dr. David Simpson - “Diamond Quantum Biosensors; Opportunities and Challenges”

    Nanodiamonds are carbon-based nanomaterials that have attracted significant attention over the past decade. Fluorescent nanodiamonds (FNDs) provide a unique range of chemical, physical, and biological properties which have driven their application in the fields of drug delivery, tissue engineering, bioimaging and quantum biosensing. Recent studies exploiting the quantum properties of the nitrogen-vacancy (NV) centre in FNDs have demonstrated the detection of magnetic, electric, and temperature fields, as well as pH, redox and radical species. These quantum sensors therefore open up new and exciting opportunities to monitor biological activity at the nanoscale.  In this talk, I will outline our efforts in applying FND probes to a range of biological problems. I will describe how these materials can be used to enhance to probe the intracellular temperature of living cells and monitor paramagnetic molecules in solution. I will discuss our recent work exploiting 2D NV imaging arrays for magnetic microscopy. In particular, I will show how these magnetic imaging techniques can be used to non-invasively map the magnetic properties of iron-oxide complexes in biological systems at the sub-cellular scale. I will also discuss the future possibilities of these technologies and how they might be applied to address significant and outstanding questions in biology.

    Professor Somnath Bhattacharyya - “Diamond-Based Hybrid Qubit System for Quantum Computation Technology“

    There is a surge in exploring the best qubit platform for building efficient quantum computers suitable for complex operations. A qubit is analogous to the binary bit seen in a conventional computer. We show the potential for a diamond-based hybrid quantum system combing electrical (superconducting) and optical (nitrogen-vacancy centers) techniques. Superconducting qubit technology typically involves the fabrication of various logic elements based on Josephson junctions using standard superconducting materials such as Al or Nb. Boron-doped superconducting diamonds are however attractive due to better resistance to external perturbations. Considering a recent discovery of triplet-spin-based superconductivity in nanocrystalline diamond films and that diamond presents well-established quantum states in the form of nitrogen-vacancy centers (NV-centers), diamond demonstrates a potential platform for the realization of all diamond-based quantum circuitry. We advance the understanding of superconducting order parameters in boron-doped nanodiamond films and as a new type of qubit system through the designing of the resonator and superconducting quantum interference devices. Quantum information can be exchanged between a superconducting diamond loop (with a phase-slip qubit junction) and an ensemble of spins (NV- centers) attached to a microwave line of the diamond nanowire that would allow us to initialize, control through microwave circuitry, and perform measurements via an optical interface. Moreover, the diamond NV- centers offer ‘holonomic’ control of qubits for the acquisition of geometric phase which can be added to the hybrid qubit system. The holonomic control of qubits implemented in a ‘nine-level’ NV center is demonstrated by using IBM Qe. This modeling shows a long coherence time of a system of multiple NV centers and also uses the multiple ‘dark’ states present in the NV centers. Such a hybrid quantum system will be useful for studying complex quantum many-body problems and quantum artificial intelligence or vision.

    Nick Vamivakas - “NV Center Quantum Science”

    Nitrogen vacancy center defects in nanodiamonds present multiple opportunities for quantum information technology applications. In this talk I will describe our groups efforts in quantum enhanced sensing of magnetic fields and temperature using the NV-center in nanodiamond. A widefield diffraction-limited imaging system has been built that enables the acquisition of widefield magnetic and temperature data.  I will also describe a new frontier in optomechanics – levitated optomechanics – that utilizes an optical tweezer in high vacuum to realize an optically controlled optomechanical system. When the tweezed particle is a nanodiamond NV center degrees of freedom become engaged and new approaches to sensing and testing quantum foundations become possible.

2021

  • Dr. Jean-Philippe Tetienne - “Widefield Quantum Diamond Microscopy: Recent Progress and Future Challenges”

    Widefield quantum diamond microscopy is a technique first experimentally demonstrated in 2010, which employs a dense layer of nitrogen-vacancy (NV) centers near the surface of a bulk diamond as a sensing array. The NV layer is interrogated in a widefield optical microscope to produce spatially resolved maps of local quantities such as magnetic field, electric field and lattice strain, providing potentially valuable information about a sample or device placed in proximity. In the last decade, this technology has seen rapid development and demonstration of applications in various areas across condensed matter physics, geoscience and biology. However, there remain several technical challenges that need to be solved for the technique to see wider adoption especially outside the diamond community. In this talk, I will present our recent work on addressing some of these challenges. First, I will discuss the issue of diamond-sample interfacing, and introduce the concept of widefield diamond probe, which provides a convenient method to rapidly image a sample while reliably minimizing diamond-sample standoff. Next, I will address the materials challenge, discussing the pros and cons of different diamond host materials and NV creation methods for widefield imaging applications, informed by an experimental comparative study. I will then describe the extension of widefield quantum diamond microscopy to cryogenic conditions, and its application to the study of superconductivity and 2D magnetism, highlighting some of the limitations of the technique. Finally, I will discuss some further technological advances that could result in a practical, accessible, high-throughput widefield quantum diamond microscope.

    Dr. Aldona Mzyk - “Future of Drug Screening and Clinical Diagnostics Through Free Radicals Detection With Fluorescent Nanodiamonds”

    Free radicals (FRs) are omnipresent and one of the key players in the ageing process on a molecular level. Despite their relevance, information about FRs is sparse and therefore their use as clinical biomarkers is very limited. Since FRs are short lived and reactive, it is challenging to detect them with the state of the art methodology. Recently, we have proved that nanodiamond magnetometry is a game changer and allows us to visualize free radical generation in real-time in single cells with nanoscale resolution.

    We are running several clinically relevant studies. In one of the projects, we have been investigating FRs generation in samples from arthritis patients. Arthritis is a common disease which is characterized by a decline of cartilage in joints. It can lead to disabilities and diminished quality of life. The two most common types of arthritis are osteoarthritis (OA) where cartilage damage occurs in degenerative diseases and rheumatoid arthritis (RA) where the decline occurs during chronic inflammation of joints. We have found significant difference in level of free radicals in RA and OA synovial fluids and derived cells. The proof-of-concept experiment has also shown that nanodiamond magnetometry enables to monitor efficiency of anti-inflammatory therapeutics in real-time.

    Apart from the arthritis research, we have shown a great potential of using nanodiamond magnetometry to investigate a free radical-based theory of male infertility. Herein, the unknown factor was the source of radicals that play a role in the sperm maturation process. The nanodiamond magnetometry allowed us to identify the prominent source of radical generation in sperm maturation and shed a new light on a role of progesterone.

    In my talk I will also address a few other exciting examples of biological processes with clinical relevance where the role of free radicals is waiting to be explored. I will show how our work opens a new perspective to explore unknown aspects of oxidative stress and brings potential for testing of newly developed drugs.

    Professor Carlos Meriles - "Optical Activation and Detection of Charge Transport Between Individual Color Centers in Room-Temperature Diamond"

    Charge control of color centers in semiconductors promises opportunities for novel forms of sensing and quantum information processing. In this presentation, I will describe recent work combining confocal fluorescence microscopy and magnetic resonance protocols to induce and probe charge transport between discrete sets of engineered nitrogen-vacancy (NV) centers in diamond, down to the level of individual defects. In our experiments, a ‘source’ NV undergoes optically-driven cycles of ionization and recombination to produce a stream of photo-generated carriers, one of which we subsequently capture via a ‘target’ NV several micrometers away. We use a spin-to-charge conversion scheme to encode the spin state of the source color center into the charge state of the target, in the process allowing us to set an upper bound to carrier injection from other background defects. We attribute our observations to the action of unscreened Coulomb potentials producing giant carrier capture cross-sections, orders of magnitude greater than those typically attained in ensemble measurements. Besides their fundamental interest, these results open intriguing prospects for applications ranging from the use of free carriers to expose otherwise invisible point defects, to establishing a quantum bus to mediate effective interactions between paramagnetic defects in a solid-state chip.

    Professor Richard Jackman - "Recent Experiences with Nanodiamond at UCL: from Biotechnology to Electronics"

    Nanodiamonds (NDs), here taken as the ~5nm size ND particles produced by detonation processes, have been used as both electronic and biological materials by the Diamond Electronics Group (DEG) at UCL. By virtue of their size the properties of these NDs are controlled by their surface as opposed to their bulk. In the case of electronics, the often sp2-sp3 composite ND surface, along with various stable surface chemical groups, can be a drawback. However, treatments which enable the properties of diamond to be harnessed in NDs, to enable the fabrication of electron amplifiers (NEA) and diodes (doping) for various applications (night vision, sensors) have been developed; these will be discussed in this presentation. In contrast, the often complex, but more naturally occurring, properties of the surfaces of NDs have been shown to be very interesting in a biological context. We have found that both the chemical and physical (curvature) nature of NDs make them attractive for the adhesion of living cellular materials. In this manner patterns of nano-diamonds have been used to generate fully functional living neural networks (hippocampal neurons), which will be addressed here. In the context of stem cells both human neural material, and cells derived from adipose (fat) tissue have been studied in terms of their interaction with NDs. Interestingly, in the case of the nature of stem cell differentiation, their fate in terms of what type of cell they become, ND termination (H- or O-) can play a determining role. This, and the broader use of NDs in stem cell technology will be discussed.

    Professor Robert J. Hamers - "Controlling and Manipulating the Surface Chemistry of Diamond"

    While diamond has many unique properties, controlling the surface chemistry is essential to many of its uses in science and technology. In this talk I will discuss methods of surface functionalization of diamond with molecules relevant to nanotechnology, biology, and quantum-based chemical sensing, and I will discuss how to probe the surface chemistry using chemically selective methods including XPS, FTIR, NMR, EPR, and optical methods.

    Professor Jacqueline Krim - "Nanodiamonds, energy efficiency and climate change: How friction and lubrication are impacted by nanodiamonds"

    What is the potential impact on global warming if combusion engines worldwide were made to be 10% more efficient? Nanodiamonds, when added to engine oil, can in fact reduce wear and increase fuel economy by 10 to 25%. They do not however, reduce friction in all cases and can increase both wear and friction for certain materials combinations. In the first part of my talk, I will overview our group’s macroscale and nanoscale measurements documenting the impact of nanodiamond additives on friction levels for a variety of materials, including oil, water and conventional engine oil additives. In the second part of my talk, I will work examples to find the carbon emissions reductions associated with specific energy efficiency improvement levels and the magnitude of the associated global warming levels that might be avoided.

    Professor Carlo Bradac - "Diamond-based nanothermometers"

    Nanoscale thermometry is a key enabler for proposed applications in medicine, nanoelectronics, biology and solid-state semiconducting devices. Over the last decade, great efforts have been devoted to the development of advanced nano-thermometry techniques. Raman-based approaches were amongst the field’s trailblazers, yet as they require large sample volume and suffer from low signal-to-noise ratio, they have been recently contended by a new class of nanoscale optical thermometry methods. These are mainly based on fluorescent nanoparticles of various nature and are attractive because of their photostability, brightness and small size. In this lecture I will present the state of the art of diamond-based nanoscale thermometry techniques, their applications and the outstanding challenges and open opportunities in the field.

    Dr. Benjamin Miller - "Fluorescent nanodiamonds for rapid, sensitive, low-cost diagnostics"

    The ongoing COVID-19 pandemic has emphasized the need for sensitive, early diagnosis of infectious diseases, crucial for reducing the impact of outbreaks. Nanoparticle-based rapid diagnostics, such as lateral flow tests, are widely used for antibody detection but often lack the sensitivity required for early detection of antigen or nucleic acid targets. Fluorescent labels have been investigated as a replacement for gold nanoparticles, which are widely used on lateral flow tests, but their sensitivity is limited by the background autofluorescence of the membrane or sample. This presentation discusses recently published work from our lab incorporating fluorescent nanodiamonds into lateral flow tests with the aim of improving sensitivity. In addition to their attractive properties for in vitro biosensing, including brightness and low cost, fluorescent nanodiamonds allow for selective manipulation of their emission with an external electromagnetic field. This allows their emission to be specifically modulated at a fixed frequency and separated from background autofluorescence in the frequency domain. Although significant challenges remain in translating this proof-of-concept to a field-ready diagnostic, this work demonstrates the additional sensitivity nanodiamonds could offer in numerous diagnostic test formats, assays and diseases, with the potential to improve early diagnosis of diseases, benefiting patients and populations. Miller, B.S., Bezinge, L., Gliddon, H.D. et al. Spin-enhanced nanodiamond biosensing for ultrasensitive diagnostics. Nature 587, 588-593 (2020). https://doi.org/10.1038/s41586-020-2917-1

    Professor Abraham Wolcott - "Fundamental surface modification and synchrotron-based spectroscopy of nanoscale diamond with bromine, nitrogen and boron precursors"

    Nitrogen vacancy center (NVC) nanodiamond or fluorescent nanoscale diamond (FND) is produced via ball-milling of macroscopic high-pressure high-temperature diamond and has electronic and surfaces properties that are nearly identical to bulk diamond. While FNDs are attractive for biolabelling due to their chemical inertness and lack of cytotoxicity, few chemical routes exist to remove the carbon-oxygen bonds formed after aerobic oxidation and chemical oxidation. We focus on low-Z precursors and wish to yield new surface moieties that tune the surface dipole moment of the FND and alter their NVC photophysics (NVo/NV- charge switching). Here we use gas phase and wet chemical techniques to modify the surface with bromines, nitrogen and boron chemistry and provide definitive chemical analysis with surface sensitive spectroscopies. We found the alkyl-bromides formed with SOBr2 chemistry of alcohol-rich FNDs is exceedingly unique and does not follow the chemical stability or reactivity observed in small molecule systems such as 1-bromo-adamantane. For example, FND-Br will debrominate instantly in air at 25°C, can be cleaved thermally at 90°C in inert conditions and acid-bromides are more stable chemically than alkyl-bromides. We rationalize these findings due to the high surface energy of the brominated surface along the 111 facet, low bond dissociation energy and sterics. We exploit the facile C-Br bond and form C-N bonds using various amines at room temperature and without catalysts. A Sonogarisha-type reaction was also observed when FND-Br constructs were reacted with an alkyne-amine. Boron reactions with FND-OH in anhydrous conditions at 40°C were also performed and yielded a mixture of bonding environments, including evidence of direct C-B bond formation and the removal of C-O surface groups. This work should be of interest to researchers in physics, chemistry and engineering who require molecular control of the diamond surface, wish to tune NVC charge state probability and use FNDs for magnetic/electric field sensing and quantum communication applications.

2020

  • Dr. Philipp Reineck

    “Not all nanodiamonds are created equal: from material properties to applications in biology”

    Recorded Lecture

  • Professor Peter Pauzauskie

    “High-pressure, high-temperature molecular doping of nanodiamond”

    Recorded Lecture

  • Professor Oliver Williams

    “Nanostructured diamond and size effects”

    Recorded Lecture

  • Professor Petr Cigler

    “Molecular transducers for spin-sensitive optical sensing using nitrogen-vacancy centers”

    Recorded Lecture

  • Dr. Philipp Reineck - "Not all nanodiamonds are created equal: from material properties to applications in biology"

    High-pressure high-temperature (HPHT) nanodiamonds (ND) and detonation nanodiamonds (DND) are the most commonly used types of nanodiamonds today. While both largely consist of carbon in the form of diamond, their particle sizes and shapes, physicochemical properties, colloidal properties and optical properties vary greatly. At the same time, even within one batch of particles of the same type, the properties of individual particles can also differ significantly. The latter is a great challenge for many applications, for example nanodiamond-based quantum sensing. Addressing it requires a detailed characterization and understanding of the particle properties from the exact arrangement of individual atoms to the properties of whole particle ensembles. Based on this knowledge, the next generation of nanodiamonds can be engineered for specific applications. This presentation will summarize our recent results in the characterization and application of HPHT and detonation nanodiamonds with a focus on nanodiamond fluorescence. Topics that will be discussed include near-infrared fluorescent color centers, fluorescence from non-diamond carbon, surface functionalization, ND colloidal properties, 3D printing of NDs, the integration of HPHT NDs into biopolymers and optical fibers, and multimodal imaging in cancer cells.

    Professor Peter Pauzauskie - "High-pressure, high-temperature molecular doping of nanodiamond"

    Point defects in diamond have emerged as a leading platform for several emerging applications in quantum information science. This talk will present recent results in the synthesis and characterization of nanodiamond materials doped with both silicon and nitrogen point defects using a laser-heated diamond anvil cell (DAC). Amorphous carbon aerogels are used as precursors for diamond synthesis. A versatile range of molecular doping strategies are available for incorporating both silicon and nitrogen heteroatoms within the final diamond material. The noble gas argon is used as a quasi-hydrostatic pressure medium (P > 15 GPa) with the DAC, and laser heating (T > 1800K) is used to synthesize nanodiamonds from the amorphous carbon aerogels. Surprisingly, argon heteroatoms have been observed to incorporate within the nanodiamonds synthesized at extreme temperature and pressure. Both the negatively charged nitrogen vacancy center (NV) and the negatively charged silicon split vacancy (SiV) centers also are observed to form within nanodiamonds [Crane et al., Science Advances (2019) DOI: 10.1126/sciadv.aau6073]. The pressure dependence of the SiV centers zero-phonon line agrees well with ab initio quantum cluster calculations, indicating its potential for applications as a pressure sensor at extreme conditions.

    Professor Oliver Williams - "Nanostructured diamond and size effects"

    Diamond has a number of extreme properties such as its hardness and superlative thermal conductivity that have been exploited for decades. As with any material, these properties can deviate substantially at the nanoscale. However, carbon also exhibits multiple allotropes, which complicate nanostructures even further as surfaces contain finite non-diamond concentrations, and surface effects become dominant with decreasing size. Small concentrations of sp2 can dominate nanodiamond properties such as optical adsorption and electrical conductivity. This presentation will focus on the production / purification of diamond nanoparticles, size effects and their application from the seeds for diamond growth through quantum colour centres to virus filtration. Particular attention will be given to the positive zeta potential, its origin and application. This effect is relatively unusual amongst materials, and its origin in diamond still not entirely understood. However, it is clear that sp2 bonding and size contribute to this effect as larger particles and bulk diamond surfaces do not exhibit it without further functionalization.

    Professor Petr Cigler - "Molecular transducers for spin-sensitive optical sensing using nitrogen-vacancy centers"

    Non-perturbing sensing techniques applicable to biological systems currently are of central interest in the biosciences. Nanodiamond is a highly biocompatible nanomaterial for construction of nanosensors, which can accommodate various photoluminescent crystal defects. Nitrogen-vacancy (NV) centers show high photostability and unique electronic sensitivity to magnetic field. Their spin properties can be read by optical means, which enables construction of various probes based on quantum mechanical interactions. If embedded in nanodiamond particles, NV centers can be exposed to biological environment and report sensitively on the spin-related processes occurring in a close vicinity of the particle. Molecular transducers designed for NV centers transposing the presence of particular analytes to a selective and unambiguous readout will be presented. Different types of surface architectures will be shown. Optical nanosensors designed for selective measurements of pH, redox potential, and ascorbate under physiological conditions will be discussed.

2020 Lecture Series

  • Dr. Ashok Ajoy

    “Optically Hyperpolarized Nanodiamonds: New Avenues for Signal Enhanced NMR and MRI”

    Recorded Lecture

  • Dr. Melissa Mather

    “Quantum sensing in biological systems using Nitrogen Vacancy defects in diamond”

    Recorded Lecture

  • Dr. Vadym Mochalin

    “Progress in Nanodiamonds for Novel Composites and Biomedical Applications”

    Recorded Lecture

  • Dr. Diana Berman

    “Tribological and Bactericidal Effect of Nanodiamonds as Potential Lubricants for Artificial Joints”

    Recorded Lecture

  • Dr. Romana Schirhagl

    “Diamond Magnetometry for Measuring Free Radicals in Living Cells”

    Recorded Lecture

  • Dr. Alex Shames

    “Paramagnetic Defects and Color Centers In Particulate Ib Type HPHT Diamonds”

    Recorded Lecture

  • Dr. Sabine Szunerits

    “Antiviral and Antibacterial Inhibitors: From Nanodiamonds to Carbon Quantum Dots (CQDs)”

    Recorded Lecture

  • Dr. Marco Torelli

    “Targeted Nanodiamond In Biological Systems”

    Recorded Lecture

  • Dr. Jean-Charles Arnault

    “Detonation nanodiamonds and overproduction of hydroxyl radicals and solvated electrons under ionizing radiation”

    Recorded Lecture

  • Dr. Anke Kruger

    “Functionalization of Nanodiamond for Biomedical Applications”

    Recorded Lecture

  • Dr. Igor Vlasov

    “Is it possible to produce optically indistinguishable SiV centers in nanodiamonds?”

    Recorded Lecture

  • Nicholas Nunn

    “Controlled Production of a Vibrant Color Spectrum of Fluorescent Diamond Particles”

    Recorded Lecture

  • Dr. Ashok Ajoy - "Optically Hyperpolarized Nanodiamonds: New Avenues for Signal Enhanced NMR and MRI"

    Diamond particles hosting negatively charged nitrogen vacancy (NV-) centers have recently emerged as an intriguing platform to dynamically polarize nuclear spins inside and potentially outside the crystal lattice. This presentation surveys some recent work on the topic by our groups including the development and implementation of spin polarization methods insensitive to the orientation of the diamond particles, as well as proof-of-principle applications such as dual fluorescence and magnetic resonance imaging of diamond particles arrays. Further, we introduce recent observations using particles of varying dimensions down to nm sizes, and show that diamond annealing at elevated temperatures has important effects on the hyperpolarization levels, enhancing them by above an order of magnitude over materials annealed through conventional means. Electron and nuclear spin resonance measurements show this response correlates with NV- and 13C relaxation and coherence times, which points to improved recovery of the diamond lattice from radiation damage.

    Dr. Melissa Mather - "Quantum sensing in biological systems using Nitrogen Vacancy defects in diamond"

    The Nitrogen-Vacancy (NV) color center in diamond has emerged as a high performance quantum sensor with application areas including photonics, quantum information science and the life sciences. Quantum physicists have primarily led the development of NV based quantum sensing in the pursuit of quantum computing. As such, there is a paucity of studies addressing biologically important questions using NV based optical sensing. Moreover, optical sensing protocols reported to date rely on complicated experimental protocols and equipment not readily available in a life sciences laboratory. This presentation will provide an overview of current work in our laboratory demonstrating accessible strategies with application in the life sciences and medicine. In particular, exemplar studies will be presented demonstrating sensing in highly viable populations of differentiated neural stem cells functioning as a connected neural network using NV nanodiamonds and electrospun polymer nanofibers embedded with NV nanodiamonds, which recapitulates the nanoscale architecture and topography of the cell niche. Protocols for real time sensing of paramagnetic species in solution will be reported, which have future application in sensing of biologically endogenous paramagnetic species in live cells. It is anticipated that this presentation will encourage applied scientists to harness the tremendous potential NV optical sensing has to sense currently undetectable signals and to improve existing methods of sensing using an optical measurement platform with far-reaching consequences in the life sciences and beyond.

    Dr. Vadym Mochalin - "Progress in Nanodiamonds for Novel Composites and Biomedical Applications"

    Nanodiamond powders produced by detonation synthesis offer great potential in many applications (1), including novel nanocomposites (2) and biomedical applications (3). In the area of nanocomposites, much of work has been focused on polymer matrix composites, while significantly less has been done with other matrices, such as ceramics and metals (4). At the same time, nanodiamonds have great potential in reinforcing as well as improving optical properties and wear behavior of metal- and ceramic-matrix composites. We will review our progress in developing well-dispersed nanodiamonds (5) for composite applications with an emphasis on novel and less studied nanodiamond-ceramic and nanodiamond-metal composites. Manufacturing and processing techniques, as well as properties of the composites, will be discussed. Another hot area of applications for nanodiamond is biomedical imaging and drug delivery. We will discuss our recent progress in drug delivery with nanodiamonds, emphasizing the effects of nanodiamond surface chemistry, and present novel processing techniques to produce luminescent nanodiamond particles from HPHT luminescent diamond for bioimaging, labeling, and other applications.

    1. Mochalin, V. N.; Shenderova, O.; Ho, D.; Gogotsi, Y., The properties and applications of nanodiamonds. Nature Nanotechnology 2012, 7 (1), 11-23.

    2. Mochalin, V. N.; Gogotsi, Y., Nanodiamondpolymer composites. Diam. Relat. Mat. 2015, 58, 161-171.

    3. Turcheniuk, K.; Vadym, N. M., Biomedical applications of nanodiamond (Review). Nanotechnology 2017, 28 (25), 252001.

    4. Turcheniuk, K.; Mochalin, V. N., Adsorption behavior and reduction of copper (II) acetate on the surface of detonation nanodiamond with well-defined surface chemistry. Carbon 2016, 109, 98-105.

    5. Turcheniuk, K.; Trecazzi, C.; Deeleepojananan, C.; Mochalin, V. N., Salt-Assisted Ultrasonic Deaggregation of Nanodiamond. ACS Applied Materials & Interfaces 2016, 8 (38), 25461-25468.

    Dr. Diana Berman - "Tribological and Bactericidal Effect of Nanodiamonds as Potential Lubricants for Artificial Joints"

    The artificial joints in forms of knee and hip implants are widely used for the treatment of degenerative joint diseases and trauma. Current clinically-used implants, traditionally made from polymer-on-metal structures, often suffer from high friction and wear, leading to associated inflammation and infection resulting in ultimate failure of the artificial joints. Here, we propose an alternative solution to this tribologically-induced failure of the joint materials. We demonstrate that friction and wear behavior of ultra-high-molecular-weight polyethylene (UHMWPE) and titanium tribopair, used to mimic the artificial joint interface, can be improved by introducing nanodiamond (ND) particles in the sliding contact. Analysis of the wear track formed during sliding indicates the formation of a carbon-rich tribolayer of embedded NDs which improves tribological properties of the contacting surfaces and significantly suppressed the wear of the UHMWPE surface. In addition to the improved lubrication characteristics, NDs exhibit high biocompatibility with the bone cells and promising antibacterial properties against S. aureus, the most common strain associated with artificial joint infection. These results indicate that NDs can be used as a promising nontoxic human-body lubricant with anti-wear and antibacterial features, thus demonstrating their great potential to treat artificial joint complications through intra-articular injection.

    Dr. Romana Schirhagl - "Diamond Magnetometry for Measuring Free Radicals in Living Cells"

    Free radicals play a key role in multiple processes in healthy cells including signalling, food degradation or immune responses. But they are are an indication of something being wrong in a cell and thus are important for numerous diseases including cancer, cardiovascular diseases, viral or bacterial infection or ageing. However, despite their relevance free radicals are challenging to measure with the state of the art. My group is using fluorescent nanodiamonds including NV centers for this purpose. We make use of the quantum sensing ability to detect the spin noise from radicals. With this technology we can obtain a magnetic resonance signal in real time and learn more about the ageing process, differentiate genetic mutants or understand better how the cell responds to a viral infection. Here I will show our first results on this topic.

    Dr. Alex Shames - "Paramagnetic Defects and Color Centers In Particulate Ib Type HPHT Diamonds"

    Alexander I. Shames Department of Physics, Faculty of Natural Sciences, Ben-Gurion University of the Negev, P.O. Box 653, 8410501 Beer-Sheva, Israel Irradiation of synthetic and natural diamonds with high energy particles produces optically active crystallographic defects that are useful for a variety of applications. Within the N-related family of optical defects, the nitrogen-vacancy defect (NV-) has been received great consideration due to numerous applications in both emerging and mature technologies: background-free and long-term cell imaging in the red/near infrared spectral region, tracing of cell progeny, flow cytometry, super-resolution imaging, correlative and multimodal microscopy, labeling of low-abundance cellular components. Significant part of defects in diamonds, including NV- centers and their precursors carry unpaired spins and, thus, are paramagnetic. It turns Electron Paramagnetic Resonance (EPR) spectroscopy into powerful practical tool for successive development and optimization of micro- and nano-diamonds having useful properties specifically pre-engineered for biomedical applications. Conventional CW X-band EPR spectra recorded within so called “half-field†(around g=4.00) region allow both classification and reliable quantification of paramagnetic defects having electronic spin S³1 for bulk single- and poly-crystalline diamond samples. Thus, EPR studies of initial nitrogen content, fluence, annealing and nanonization (size) dependences allow optimization of the technological processes for the manufacturing of bright micro- and nano-sized fluorescent diamonds. EPR also provides information of electronic spin-lattice (T1e) and spin-spin (T2e) relaxation times of all magnetic species in the hosting diamond lattice. These parameters are found to be indicative to quality of triplet centers as hyperpolarization agents.

    Dr. Sabine Szunerits - "Antiviral and Antibacterial Inhibitors: From Nanodiamonds to Carbon Quantum Dots (CQDs)"

    The constant emergence of new viruses, as currently evidenced with the newly emerged Coronavirus disease 2019 (COVID-19) associated with severe respiratory distress, has considerable impact to the society, the economy and public health. The general absence of specific antiviral therapeutics has made the search for antiviral drugs and therapeutics a challenging research task. Viruses pose a considerable challenge to the body’s immune system as they hide inside cells making it difficult for antibodies to reach them. In contrast to bacterial infections, which are mostly treated using antibiotics, the immunization against viral infections is not always possible. Multivalent binding interactions have lately been considered for the development of new therapeutic strategies against bacterial and viral infections. Multivalent polymers, dendrimers and liposomes have successfully targeted pathogenic interactions. While a high synthetic effort is often needed for the development of such therapeutics, the integration of multiple ligands onto nanostructures turned to be a viable alternative. Particles modified with multiple ligands have the additional advantage of creating a high local concentration of binding molecules. In this talk I will give several examples on the interest of carbon-based nanostructures, notable nanodiamonds and carbon quantum dots (CQDs) for the treatment of viral and bacterial infections. Different glycan-modified nanodiamonds revealed themselves to be of great promise as useful nanostructures for combating microbial infections. The antiviral activity of dcarbon quantum dots (CQDs) for the treatment of human coronavirus HCoV-229E infections will be discussed further.

    References:

    1. A. Åoczechin, K. Saron, A. Barras, S. Belouzard, Y.-T. Chen, N. Metzler-Nolte, R. Boukherroub, J. Dubuisson, S. Szunerits, ACS Applied Materials and Interfacs 2019, 11, 46, 42964-42974. Functional Carbon quantum dot as medical countermeasures to humancorona virus (HCoV)

    2. R. Jijie, A. Barras, J. Bouckaert, N. Dumitrascu, S. Szunerits, R. Boukherroub. Colloids and Surfaces B: Biointerfaces 2018, 170, 347-354. Enhanced antibacterial activity of carbon dots functionalized with ampicillin combined with visible light triggered photodynamic effects.

    3. K. Nekoueian, M. Amiri, M. Sillanpe, F. Marken, Boukherroub, S. Szunerits. Chemical Society Reviews 2019, 48, 4281-4316. Carbon-based quantum particles: an electroanalytical and biomedical perspective

    4. R. Jijie, A. Barras, F. Teodorescu, R. Boukherroub, S. Szunerits, Molecular Systems Design & Engineering, 2017, DOI: 10.1039/C7ME00048K, Advancements on the molecular design of nanoantibiotics: current level of development and future challenges.

    5. A. Barras, F. A. Martin, O. Bande, J.-S. Baumann, J.-M. Ghigo, R. Boukherroub, C. Beloin, A. Siriwardena, S. Szunerits, Nanoscale 2013, 5, 2307-2316, Glycan-functionalized diamond nanoparticles as potent E. coli antiadhesives.

    6. M. Khanal, F. Larsonneur, V. Raks, A. Barras, R. Boukherroub, J.-M. Ghigo, C. Ortiz Mellet, V. Zaitsev, J. M. Garcia Fernandez, C. Beloin, A. Siriwardena, S. Szunerits, Nanoscale 2015, 7, 2325-2335, Inhibition of Escherichia coli adhesion to biotic surfaces and of biofilm formation on abiotic surfaces by trimeric cluster mannosides conjugated to iamond nanoparticles.

    7. M. Khanal, T. Vausellin, A. Barras, O. Bande; K. Turcheniuk, M. Benazza, Zaitsev, C. M. Teodurescu, R. Boukherroub, A. Siriwardena, J. Dubuisson, S. Szunerits, ACS Applied Materials & Interfaces 2013, 5, 12488-12498, Phenyl-acid-modified nanoparticles: potential antiviral therapeutics.

    8. Barras, Q. Pagneux, F. Sané, R. Boukherroub, D. Hober, S. Szunerits, ACS Applied Materials & Interfaces 2016, 13, 9004-9013, Inhibition of Herpes simplex virus type 1 entry by functional carbon nanodot

    Dr. Marco Torelli - "Targeted Nanodiamond In Biological Systems"

    Data related to sensing and targeting applications of diamond nanoparticles will be discussed. Fluorescent nanodiamond was targeted to 4T1 mammary tumors in mice by conjugation with VEGF for targeting to VEGF receptors. Recently it was realized that thermal annealing techniques developed at Adamas in collaboration with CUNY (Prof. Zaitsev) produced the capacity for multicolor fluorescence. Applications for the labeling of blood clots were shown. This method of thermal annealing imparted improved sensitivity of diamond particles to external magnetic fields. These developments will be discussed in the context of biological applications, such as background subtraction.

    Relevant Works:

    Torelli, M. D.; Rickard, A. G.; Backer, M. V.; Filonov, D. S.; Nunn, N. A.; Kinev, A. V.; Backer, J. M.; Palmer, G. M.; Shenderova, O. A., Targeting fluorescent nanodiamonds to vascular endothelial growth factor receptors in tumor. Bioconjugate Chem. 2019, 30 (3), 604-613.

    Torelli, M. D.; Nunn, N. A.; Shenderova, O. A., A Perspective on Fluorescent Nanodiamond Bioimaging. Small 2019, 0 (0), 1902151.

    Torelli, M. D.; Nunn, N. A.; Jones, Z. R.; Hamers, R. J.; Vedelaar, T.; Padamati, S. K.; Schirhagl, R.; Shames, A. I.; Danilov, E. O.; Zaitsev, A.; Shenderova, O. A., High Temperature Treatment of Diamond Particles Toward Enhancement of Their Quantum Properties. Frontiers Research 2020. DOI: 10.3389/fphy.2020.00205

    Dr. Jean-Charles Arnault - "Detonation nanodiamonds and overproduction of hydroxyl radicals and solvated electrons under ionizing radiation"

    Aqueous suspensions of detonation nanodiamonds behaving different surface chemistries (hydrogenated, oxidized) were irradiated by keV or MeV photons. Hydroxyl radicals were quantified using a very sensitive, nanoparticle-compatible, coumarin-based protocol. Only plasma hydrogenated nanodiamonds led to 50% more radicals, for irradiation doses and ND concentrations relevant in nanomedicine. For the first time, solvated electrons were quantified after keV irradiation of both suspensions. In the presence of plasma hydrogenated nanodiamonds, hydroxyl radicals and solvated electrons were available in solution in equivalent and higher amounts than in water only. Among involved mechanisms, interfacial water could play an essential role in radicals’ production in solution when detonation H-ND are irradiated, as for other nanomaterials.

    Dr. Anke Kruger - "Functionalization of Nanodiamond for Biomedical Applications"

    Nanodiamond is a material very much suited for biomedical applications due to its benign behaviour, inertness, and biocompatibility. Also the ability to attach a variety of functional moieties such as proteins, labels, sensors, drugs etc. in a very stable and controlled fashion make it the basis for applications such as targeted drug delivery, sensing, tissue engineering etc. This lecture will present recent developments in the field of surface functionalization of nanodiamond for biomedical applications.

    Dr. Igor Vlasov - "Is it possible to produce optically indistinguishable SiV centers in nanodiamonds?"

    Diamond nanoparticles with optically active color centers can be used in nanoscale devices for quantum networking and sensing. A particular interest is focused on nanodiamonds (ND) containing negatively charged silicon-vacancy (SiV) centers. Here, I will present our recent studies on fluorescence properties of ensemble and single SiV centers in CVD and HPHT diamond particles, using off-resonant and resonant excitations, at room and cryogenic temperatures. The width of single SiV emission lines in HPHT nanodiamonds, synthesized from adamantane, turns out to be narrower than in CVD diamond grown epitaxially on a <100> -oriented substrate. Nevertheless, the inhomogeneous line broadening determined for SiV ensembles in the nanodiamonds is significantly inferior to the similar parameter found for <100> -oriented CVD diamond. The ability to produce nanodiamonds containing optically indistinguishable SiV ensembles is discussed.

    Nicholas Nunn - "Controlled Production of a Vibrant Color Spectrum of Fluorescent Diamond Particles"

    We will report on a breakthrough method of production of multicolor diamond particulates using a rapid thermal annealing (RTA) approach with precise temperature and time control, enabling annealing of diamond particulates up to 2100 °C without extensive graphitization. The RTA method generates conditions which allow formation of one-, two- and three-atom nitrogen complexes with vacancies in electron irradiated type Ib synthetic diamond, providing vibrant luminescence in the red, green and blue spectral ranges, correspondingly. We will demonstrate opportunities for particulate diamond in a plethora of fluorescence imaging applications in biological and industrial fields based on controlled and highly reproducible formation of specific color centers previously not possible in type Ib synthetic diamond particles in micron- and nanometer size ranges.