[论文解读] Is a quantum biosensing revolution approaching?

Giulia Petrini, Ekaterina Moreva+6 more|arXiv (Cornell University)|Jun 1, 2020

Atomic and Subatomic Physics Research参考文献 169被引用 13

一句话总结

本综述探讨了金刚石中氮-vacancy（NV）中心作为生物相容性量子传感器在生物系统中检测微弱电磁场和热场的潜力。利用光学探测磁共振（ODMR），NV中心可在室温下实现纳米级空间分辨率和亚毫开尔文温度灵敏度，已成功检测神经元和心肌的磁信号，使其成为神经科学和诊断学的变革性工具。

ABSTRACT

Understanding the human brain remains one of the most significant challenges of the 21st century. As theoretical studies continue to improve the description of the complex mechanisms that regulate biological processes, in parallel numerous experiments are conducted to enrich or verify these theoretical predictions and with the aim of extrapolating more accurate models. In the field of magnetometers for biological application, among the various sensors proposed for this purpose, NV centers have emerged as a promising solution due to their perfect biocompatibility and the possibility of being positioned in close proximity and even inside the cell, allowing a nanometric spatial resolution. There are still many difficulties that must be overcome in order to obtain both spatial resolution and sensitivity capable of revealing the very weak biological electromagnetic fields generated by neurons (or other cells). However, over the last few years, significant improvements have been achieved in this direction, thanks to the use of innovative techniques, which allow us to hope for an early application of these sensors for the measurement of fields such as the one generated by cardiac tissue, if not, in perspective, for the nerve fibers fields. In this review, we will analyze the new results regarding the application of NV centers and we will discuss the main challenges that currently prevent these quantum sensors from reaching their full potential.

研究动机与目标

• 评估NV中心作为量子生物传感器检测弱生物电磁场的可行性。
• 解决在活体生物系统中实现高空间分辨率和高灵敏度的挑战。
• 分析近期基于NV的神经元和心肌活动传感的实验进展。
• 识别限制其体内应用的关键技术障碍，如激光功率限制和退相干时间。
• 评估NV传感器通过检测微弱生物电磁信号在神经退行性疾病早期诊断中的潜力。

提出的方法

• 利用合成金刚石中的氮-vacancy（NV）缺陷作为具有光学可调自旋态的量子传感器。
• 采用光学探测磁共振（ODMR）实现室温下NV自旋态的初始化和读出。
• 应用脉冲测量协议以延长自旋退相干时间并提高信噪比。
• 将激光激发功率优化至数毫瓦量级，以在活细胞环境中平衡灵敏度与生物相容性。
• 施加横向偏置磁场（约3 mT）以提高温度传感灵敏度。
• 采用约1 µm³的传感体积，在保持纳米级空间分辨率的同时最小化光损伤。

实验结果

研究问题

• RQ1 NV中心能否检测到人类神经元动作电位产生的微弱磁场？
• RQ2 在生物环境中，基于NV的传感器可检测的最小磁场强度是多少？
• RQ3 如何将激光功率最小化以在保持高传感灵敏度的同时维持细胞活力？
• RQ4 NV传感器在多大程度上可分辨细胞微域中的局部热梯度？
• RQ5 需要哪些技术改进才能实现在神经元中检测单个动作电位？

主要发现

• 在80 mW激光功率下，NV中心在1 µm³传感体积中实现约4.8 mK/Hz¹ᐟ²的温度灵敏度，超过大多数生物过程的需求。
• 当激光功率降低至数毫瓦时，温度灵敏度仍足以实现亚一度的精度来分辨生物过程。
• 基于NV的传感器已成功检测到磁螺旋菌和乌贼轴突产生的磁场，其强度远高于人类神经元产生的磁场。
• 通过脉冲协议和工程化金刚石样品优化的NV传感器，目前具备检测心肌表面心脏磁信号的能力。
• 由于耦合较弱，单个动作电位磁场的检测仍具挑战性，但集群神经元活动是近期可行的目标。
• 与线粒体活动和神经递质释放相关的局部热梯度可利用基于NV的测温技术可靠监测。