Nitrogen-vacancy center magnetic imaging of Fe3O4 nanoparticles inside the gastrointestinal tract of Drosophila melanogaster
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2023-12-05 |
| Journal | Nanoscale Advances |
| Authors | Niklas Mathes, Maria Comas, Regina Bleul, Katrijn Everaert, Tobias Hermle |
| Institutions | Fraunhofer Institute for Microengineering and Microsystems, Carl Zeiss (Germany) |
| Citations | 8 |
| Analysis | Full AI Review Included |
Technical Documentation: NV Center Diamond for Widefield Magnetic Imaging
Section titled âTechnical Documentation: NV Center Diamond for Widefield Magnetic ImagingâThis document analyzes the requirements for high-resolution Nitrogen-Vacancy (NV) center magnetometry, specifically focusing on the detection of magnetic nanoparticles (MNPs) in biological systems, and outlines how 6CCVDâs specialized MPCVD diamond products meet and exceed these technical demands.
Executive Summary
Section titled âExecutive Summaryâ- Core Achievement: Demonstrated widefield NV center magnetometry for high spatial resolution imaging of FeâOâ magnetic nanoparticles (MNPs) accumulated within the gastrointestinal tract of Drosophila melanogaster larvae.
- Material Requirement: The technique relies on a high-purity, single-crystal diamond (SCD) substrate featuring a precisely controlled, near-surface NV layer.
- Resolution & Sensitivity: Achieved diffraction-limited spatial resolution (sub-micron) and magnetic sensitivity ranging from 5.13 to 7.65 ”T/sqrt(Hz).
- Sensor Design: The NV layer was fabricated via Chemical Vapor Deposition (CVD) overgrowth, resulting in an estimated thickness of ~400 nm and a nitrogen concentration of ~1 ppm.
- Application Potential: This study serves as a proof of principle, confirming NV center magnetometry as a powerful, non-toxic tool for detecting MNP distributions in thin tissue samples, applicable to advanced biomedical quantum sensing.
- 6CCVD Value Proposition: 6CCVD specializes in providing the necessary high-purity Optical Grade SCD substrates with custom thickness control (0.1 ”m to 500 ”m) and ultra-smooth polishing (Ra < 1 nm) essential for minimizing sample standoff and maximizing spatial resolution.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the research paper detailing the sensor material and performance metrics:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Diamond Material | Single Crystal Diamond (SCD) | N/A | CVD Overgrowth |
| NV Layer Thickness | ~400 | nm | Calculated from CVD growth parameters |
| NV Concentration (Estimated) | ~1 | ppm | Nitrogen incorporation during CVD |
| Diamond Surface Orientation | (100) | N/A | Cartesian z-axis perpendicular to surface |
| Magnetic Sensitivity (η) | 5.13 to 7.65 | ”T/sqrt(Hz) | Shot-noise limited, depending on NV orientation |
| Spatial Resolution | < 1 | ”m | Diffraction limited by fluorescence light |
| Sample Standoff Distance | Order of a few | ”m | Distance between MNP cluster and NV layer |
| Magnetic Bias Field (Bbias) | ~10 | mT | Applied to separate ODMR resonance peaks |
| Objective Magnification / NA | 20x / 0.65 | N/A | Used for widefield imaging |
| MNP Core Diameter (FeâOâ) | ~29 | nm | Single core magnetic iron oxide nanoparticles |
Key Methodologies
Section titled âKey MethodologiesâThe experiment relied on precise material synthesis and advanced quantum sensing protocols:
- MNP Synthesis: Single core FeâOâ MNPs (~29 nm diameter) were synthesized via precipitation from alkaline iron chloride solution using a continuous micromixer process.
- NV Diamond Fabrication (CVD Overgrowth): A high-purity single-crystal diamond (SCD) substrate was prepared via Chemical Vapor Deposition (CVD). Nitrogen atoms were incorporated during growth to form a near-surface NV layer (~400 nm thick, ~1 ppm N concentration).
- NV Activation: The diamond was subsequently subjected to electron irradiation and annealing to create vacancies, which combined with the incorporated nitrogen to form the negatively charged NV centers.
- Biological Sample Preparation: Drosophila melanogaster third-instar larvae were exposed to 100 ”g/mL FeâOâ MNPs for 24 hours. The GI tract was then dissected, fixed, and mounted.
- Widefield ODMR Magnetometry Setup: The tissue sample was placed directly on the diamond plate, minimizing the standoff distance to the NV layer. A magnetic bias field (~10 mT) was applied to split the eight possible NV resonance frequencies.
- Data Acquisition and Reconstruction: Optically Detected Magnetic Resonance (ODMR) spectra were recorded by sweeping the microwave frequency while monitoring the NV center fluorescence. The resulting Zeeman splitting maps were mathematically transformed using the known lattice orientation to reconstruct the full three-dimensional (x, y, z) magnetic field vector components generated by the MNPs.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThis research highlights the critical need for high-quality, customized diamond materials to advance NV center quantum sensing in biological environments. 6CCVD is uniquely positioned to supply the necessary components for replicating and extending this work.
| Research Requirement | 6CCVD Solution & Capability | Technical Advantage for Replication/Extension |
|---|---|---|
| High-Purity SCD Substrates for NV layer growth. | Optical Grade Single Crystal Diamond (SCD): We supply high-purity SCD wafers grown via MPCVD, ensuring minimal strain and low defect density, which is crucial for maximizing NV center coherence time and ODMR contrast. | Guarantees optimal quantum performance and high magnetic sensitivity (η < 10 ”T/sqrt(Hz)). |
| Precise NV Layer Depth (e.g., 400 nm) and Concentration (e.g., 1 ppm). | Custom Thickness and Doping Control: 6CCVD offers SCD layers with thicknesses ranging from 0.1 ”m up to 500 ”m. We provide precise control over nitrogen incorporation during CVD to achieve target NV concentrations. | Enables optimization of the NV layer depth to balance magnetic sensitivity and spatial resolution for specific biological targets. |
| Ultra-Smooth Surface Quality for minimal sample standoff (few microns). | Precision Polishing Services: Our SCD wafers are polished to achieve a surface roughness of Ra < 1 nm. This minimizes the critical standoff distance between the NV layer and the MNP sample. | Essential for detecting the weak stray fields of nanoscale MNPs and achieving diffraction-limited spatial resolution (< 1 ”m). |
| Large Field of View for widefield imaging. | Custom Dimensions: 6CCVD can supply SCD plates and Polycrystalline Diamond (PCD) wafers up to 125 mm in diameter, allowing researchers to scale up the widefield magnetometry area for high-throughput biological screening. | Supports imaging of larger organs or multiple samples simultaneously. |
| Integrated Microwave Delivery (required for ODMR protocol). | In-House Metalization Services: We offer custom deposition of metals including Au, Pt, Pd, Ti, W, and Cu. This capability allows for the integration of microwave transmission lines or antennas directly onto the diamond surface. | Improves microwave efficiency and simplifies the experimental setup for advanced ODMR protocols. |
Applicable Materials
Section titled âApplicable MaterialsâTo replicate or extend this research, we recommend:
- Optical Grade Single Crystal Diamond (SCD): For high-coherence NV center formation on the required (100) orientation.
- Custom Doped SCD: For precise control over the near-surface NV layer thickness (0.1 ”m to 500 ”m) and nitrogen concentration (ppm level).
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house PhD team of material scientists and quantum engineers can assist with material selection, custom doping recipes, and surface preparation protocols necessary for successful NV center magnetometry projects focused on in vivo or ex vivo MNP detection and other quantum sensing applications.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Widefield magnetometry based on nitrogen-vacancy centers enables high spatial resolution imaging of magnetic field distributions without a need for spatial scanning.