Articles techniques et présentations

This work presents the design and application of a quantum sensor using a point NV defect in a nanodiamond crystal lattice for in vitro applications. Our aim is to present the design of a quantum sensor using printed circuit boards (PCBs) and to investigate the quantum response characteristics of the NV defect based on simulated temperature and microwave (MW) field. We also aim to maintain the specific temperature required for in vitro applications. Quantum sensing using NV centers promises high-resolution magnetic imaging at the nanoscale and spectroscopic analysis of small ensembles of molecular targets. In this work, we use an NV-based nanoprobe thermometer (with a theoretical sensitivity of 10mK/√Hz, allowing access to typical temperature gradients in biological systems) to monitor the opening of temperature-sensitive TRP (Transient Receptor Potential) channels. Many different temperature-sensitive TRP channels are distributed throughout the body and are being studied as pharmacological targets in various diseases such as axonal neuropathy, chronic pain, lower urinary tract disorders and type 2 diabetes. For this purpose, we use the COMSOL Multiphysics 6.2 environment with RF, AC/DC and heat transfer modules with electromagnetic wave physics and electromagnetic heating. The first part of this work is to design a PCB structure and MW excitation that will meet the required MW homogeneity and MW resonance profile around 2.89 GHz (NV resonant frequency) using electromagnetic wave physics. In the next stage, we designed a heating element consisting of a thin layer of ITO to maintain the body temperature at 37 °C of a liquid sample containing biological material. Precise temperature control is essential to keep the cells alive. The second part of this research focuses on thermal sensing by probing of the quantum response of the NV defect through simulated MW and temperature fields. To assess the quantum response of the simulated field distribution, we employed the MatLab Live Link. Utilizing the numerical outcomes obtained from our simulations, we calculated the eigenvalues of the Hamiltonian associated with the ground state spin system of the NV defect. This enabled us to determine the electronic spin resonance shift, providing us with a comprehensive understanding of the quantum response of the nano-probe based on the designed printed circuit board (PCB) and MW stimulation sequence. In conclusion, we developed the system for the thermal and microwave excitation of the NV defect in the nanodiamond particle in the liquid environment for the probing of the selective TRP channel opening. We simulate the MW field and temperature distribution and probe the NV quantum response. This knowledge opens the possibility of manufacturing the nano-probes that can be a powerful tool for developing f.e. multi-temperature probe arrays for in vitro testing, nanoscale probes for in vivo testing, and validating TRP channel-related mechanisms of inflammation. As a consequence, the technology and biological knowledge resulting from this work will nurture technological, biomedical, and clinical research. In the long run, possibly even nano-probe-based therapeutic approaches will be developed.