Gold/diamond nanohybrids for quantum sensing applications
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2015-07-21 |
| Journal | EPJ Quantum Technology |
| Authors | PeiâChang Tsai, Oliver Y. ChĂ©n, YanâKai Tzeng, Yuen Yung Hui, Jiun You Guo |
| Institutions | National Chi Nan University, National Taiwan University of Science and Technology |
| Citations | 52 |
| Analysis | Full AI Review Included |
Technical Documentation: GNR-FND Nanohybrids for Quantum Sensing
Section titled âTechnical Documentation: GNR-FND Nanohybrids for Quantum SensingâThis document analyzes the research paper âGold/diamond nanohybrids for quantum sensing applicationsâ (Tsai et al., EPJ Quantum Technology, 2015) to highlight the critical role of high-quality MPCVD diamond precursors and to propose specific material solutions available through 6CCVD.
Executive Summary
Section titled âExecutive SummaryâThis research successfully demonstrates a dual-functional nanoplatform combining fluorescent nanodiamonds (FNDs) and gold nanorods (GNRs) for simultaneous nanoscale heating and quantum sensing.
- Core Application: Highly localized hyperthermia treatment combined with in-situ temperature and magnetic field sensing at the sub-cellular level in living HeLa cells.
- Sensing Mechanism: Optically Detected Magnetic Resonance (ODMR) utilizing the thermal and magnetic field sensitivity of Nitrogen-Vacancy (NV-) ensembles within the FNDs.
- Heating Mechanism: Near-Infrared (NIR) laser excitation (808 nm) of the GNRs, which act as efficient thermal transducers via surface plasmon resonance (SPR).
- Key Achievement: Demonstrated a temperature rise of ~10 K at 0.4 mW NIR laser power in cells, compatible with static magnetic fields (up to 6 mT).
- Material Requirement: Success hinges on high-quality, monocrystalline diamond precursors (Type Ib) to ensure stable, high-density NV- ensembles and high thermal conductivity (kD ~ 1,000 W/m · K).
- 6CCVD Value Proposition: We supply the high-purity Single Crystal Diamond (SCD) precursors necessary for manufacturing next-generation FNDs with optimized NV density and superior thermal properties.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the research paper detailing the physical and operational parameters of the GNR-FND nanohybrids:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| FND Precursor Material | Synthetic Type Ib Diamond | N/A | Medium size 140 nm powder |
| FND Diameter (Final) | ~100 | nm | Used for NV- ensemble sensing |
| GNR Dimensions | 10 x 41 | nm | Used for NIR heating |
| NIR Heating Wavelength | 808 | nm | Matches GNR Surface Plasmon Resonance (SPR) band |
| Green Probe Wavelength | 532 | nm | Used for NV- fluorescence excitation and ODMR probing |
| ODMR Crystal Field Splitting (D) | 2868.4 | MHz | Triplet ground state of NV- (field-free) |
| Thermal Shift Coefficient (ÎD/ÎT) | -0.075 | MHz/K | Used to calculate temperature rise |
| Temperature Rise (In Cells) | ~10 | K | Achieved at 0.4 mW NIR laser power |
| Maximum Temperature Rise (In Cells) | ~20 | K | Achieved at 0.8 mW NIR laser power |
| Static Magnetic Field (B) | 6.0 ± 0.2 | mT | Measured via Zeeman splitting of ODMR peaks |
| Nanothermometry Sensitivity (Cited) | 100 | mK/Hz1/2 | Achieved with a single defect center |
Key Methodologies
Section titled âKey MethodologiesâThe production of the functional FNDs and their conjugation into nanohybrids involved precise chemical and physical processing steps:
- Precursor Selection: Synthetic type Ib diamond powders (Micron+) with a medium size of 140 nm were used as the starting material.
- NV Center Creation (Radiation Damage): Diamond powders were irradiated using a 40-keV He+ beam.
- NV Center Activation (Annealing): Irradiated particles were annealed at 800 °C for 2 hours to mobilize vacancies and form NV centers.
- Surface Cleaning and Oxidation: Annealed particles underwent air oxidation at 450 °C for 1 hour.
- Surface Carboxylation: Particles were surface-functionalized with carboxyl groups using concentrated H2SO4-HNO3 (3:1, v/v) at 100 °C for 3 hours in a microwave reactor.
- Amine Grafting: Carboxylated FNDs were covalently conjugated with poly-L-arginine (PLA) using water-soluble carbodiimide crosslinkers (EDC/NHS) to create an amine-grafted surface.
- GNR Conjugation: Bare, negatively charged GNRs (after CTAB removal) were physically adsorbed onto the positively charged PLA-coated FNDs via electrostatic forces, forming the GNR-FND nanohybrids.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe successful replication and advancement of this quantum sensing technology require diamond materials with exceptional purity, controlled defect density, and precise surface engineeringâall core competencies of 6CCVD.
Applicable Materials
Section titled âApplicable MaterialsâTo replicate or extend this research, high-purity diamond precursors are essential for generating stable, high-contrast NV- centers.
| Research Requirement | 6CCVD Material Solution | Key Benefit |
|---|---|---|
| High-Purity Precursor | Optical Grade SCD Plates | Ultra-low impurity levels ensure controlled NV creation and high spin coherence times, crucial for maximizing sensitivity (100 mK/Hz1/2). |
| High NV Density | SCD (Nitrogen-Doped) | Controlled nitrogen incorporation during MPCVD growth allows for precise tuning of NV ensemble density, optimizing signal strength for nanoscale thermometry. |
| Bulk Sensing/Integration | SCD or PCD Wafers (up to 125mm) | Provides large-area substrates for integrating NV sensors into microfluidic or magnetic imaging devices, extending the application beyond FNDs. |
| Electrochemical Sensing | Heavy Boron Doped PCD (BDD) | While not used in this paper, BDD is ideal for electrochemical sensing applications that may be integrated with thermal control. |
Customization Potential
Section titled âCustomization Potentialâ6CCVDâs advanced fabrication capabilities directly address the limitations and future directions mentioned in the research paper (e.g., achieving 100% conjugation efficiency and exploring different GNR aspect ratios).
- Advanced Surface Functionalization: The paper notes the need for âmore elaborate covalent conjugation methodsâ (e.g., click chemistry). 6CCVD provides custom surface terminations (e.g., specific functional groups for azide-alkyne coupling) on both bulk SCD and PCD substrates, ensuring robust, high-efficiency bonding for complex nanohybrids.
- Custom Dimensions and Thickness: We provide SCD and PCD plates/wafers in custom dimensions up to 125 mm, with thicknesses ranging from 0.1 ”m (for thin film sensing layers) up to 10 mm (for robust substrates). This supports both nanoscale FND production and macro-scale device integration.
- High-Precision Polishing: Our SCD materials feature ultra-smooth surfaces (Ra < 1 nm), critical for minimizing scattering losses and maximizing optical detection efficiency in ODMR setups.
- Integrated Metalization: For researchers looking to integrate heating elements or microwave delivery structures directly onto bulk diamond sensors, 6CCVD offers in-house metalization services (Au, Pt, Pd, Ti, W, Cu) with precise patterning capabilities.
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house PhD team specializes in MPCVD growth parameters and defect engineering. We can assist researchers in optimizing the starting material specifications (e.g., nitrogen concentration, crystal orientation) to achieve the highest possible NV- yield and coherence time required for advanced Nanoscale Thermometry and Magnetic Sensing projects.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Recent advances in quantum technology have demonstrated the potential use of negatively charged nitrogen-vacancy (NVâ) centers in diamond for temperature and magnetic sensing at sub-cellular levels. Fluorescent nanodiamonds (FNDs) containing high-density ensembles of NVâ centers are appealing for such applications because they are inherently biocompatible and non-toxic. Here, we show that FNDs conjugated with gold nanorods (GNRs) are useful as a combined nanoheater and nanothermometer for highly localized hyperthermia treatment using near-infrared (NIR) lasers as the heating source. A temperature rise of âŒ10 K can be readily achieved at a NIR laser power of 0.4 mW in cells. The technique is compatible with the presence of static magnetic fields and allows for simultaneous temperature and magnetic sensing with nanometric spatial resolution. To elucidate the nanoscale heating process, numerical simulations are conducted with finite element analysis, providing an important guideline for the use of this new tool for active and high-precision control of temperature under diverse environmental conditions.