Breakthrough in Nanodiamond Sensor Technology for Bioimaging and Quantum Sensing
Researchers have achieved a significant breakthrough in the development of nanodiamond sensors, with quantum-grade spin properties ideal for bioimaging and biosensing applications. These enhanced sensors are poised to revolutionize fields such as medicine and energy technologies, offering transformative capabilities in detecting biological and environmental changes.
The Promise of Quantum Sensing with Nanodiamonds
Quantum sensing exploits the unique quantum properties of particles, including superposition, entanglement, and spin states, to detect subtle changes in physical, chemical, or biological environments. A promising tool in this field is nanodiamonds (NDs) embedded with nitrogen-vacancy (NV) centers—defects in the diamond lattice where nitrogen atoms replace carbon atoms near vacancies. When illuminated, these NV centers emit photons that retain stable spin information, responding to magnetic fields, electric fields, and temperature changes.
Using optically detected magnetic resonance (ODMR), scientists can measure fluorescence changes in NV centers under microwave radiation to detect shifts in spin states. These NDs can be engineered to interact with specific biological molecules, making them powerful tools for sensing within living systems. However, existing nanodiamonds used in bioimaging often have lower spin quality, limiting their sensitivity and accuracy in detecting subtle changes.
Groundbreaking Nanodiamond Sensors for Quantum Biosensing
A team of researchers from Okayama University in Japan, in collaboration with Sumitomo Electric Company and the National Institutes for Quantum Science and Technology, has recently developed nanodiamond sensors that are bright enough for bioimaging and have spin properties comparable to bulk diamonds. Published on December 16, 2024, in ACS Nano, the study marks a major breakthrough in the field. According to lead researcher Professor Masazumi Fujiwara, these quantum-grade NDs exhibit properties that have long been sought for applications in quantum biosensing and other advanced technologies.
Innovative Developments in Nanodiamond Production
The key challenge for ND sensors in bioimaging has been the presence of spin impurities and surface noise that disrupt spin states. To address this, the research team focused on creating high-quality diamonds with minimal impurities. They grew single-crystal diamonds enriched with 99.99% 12C carbon atoms and introduced controlled amounts of nitrogen to create NV centers. These diamonds were then crushed into NDs and suspended in water.
Enhanced Performance for Biological Applications
The resulting NDs, with a mean size of 277 nanometers, showed superior fluorescence and spin properties compared to commercially available larger NDs. They required significantly less microwave power for spin detection, had reduced peak splitting, and exhibited much longer spin relaxation times. These enhancements indicate that the NDs can maintain stable quantum states, making them ideal for accurate measurements with minimal microwave radiation—helping to avoid microwave-induced toxicity in biological cells.
Applications in Healthcare and Technology
To assess their biological sensing potential, the researchers tested the NDs in HeLa cells, confirming that they were bright enough for clear imaging and produced reliable spectra despite slight movement within the cells. The NDs were also capable of detecting minute temperature fluctuations, with a sensitivity far superior to existing NDs.
With their ability to sense temperature changes and other biological parameters, these nanodiamond sensors hold immense potential for applications such as early disease detection, monitoring battery health, and improving energy-efficient devices. Their capabilities could transform healthcare, technology, and environmental management, offering sustainable solutions for pressing global challenges, as emphasized by Professor Fujiwara.
