Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States.
Department of Electrical and Computer Engineering, University of Wisconsin-Madison , 3445 Engineering Hall, 1415 Engineering Drive, Madison, Wisconsin 53706, United States.
Anal Chem. 2018 Jan 2;90(1):769-776. doi: 10.1021/acs.analchem.7b03157. Epub 2017 Dec 11.
While there is great interest in understanding the fate and transport of nanomaterials in the environment and in biological systems, the detection of nanomaterials in complex matrices by fluorescence methods is complicated by photodegradation, blinking, and the presence of natural organic material and other fluorescent background signals that hamper detection of fluorescent nanomaterials of interest. Optically detected magnetic resonance (ODMR) of nitrogen-vacancy (N) centers in diamond nanoparticles provides a pathway toward background-free fluorescence measurements, as the application of a resonant microwave field can selectively modulate the intensity from N centers in nanodiamonds of various diameters in complex materials systems using on-resonance and off-resonance microwave fields. This work represents the first investigation showing how nanoparticle diameter impacts the N center lifetime and thereby directly impacts the accessible contrast and signal-to-noise ratio when using ODMR to achieve background-free imaging of Nnanodiamonds in the presence of interfering fluorophores. These results provide new insights that will guide the choice of optimum nanoparticle size and methodology for background-free imaging and sensing applications, while also providing a model system to explore the fate and transport of nanomaterials in the environment.
虽然人们非常有兴趣了解纳米材料在环境和生物系统中的命运和迁移，但荧光方法检测复杂基质中的纳米材料受到光降解、闪烁以及天然有机物质和其他荧光背景信号的干扰，这些信号阻碍了对感兴趣的荧光纳米材料的检测。金刚石纳米颗粒中氮空位（N）中心的光学检测磁共振（ODMR）为无背景荧光测量提供了一种途径，因为共振微波场的应用可以使用共振和非共振微波场选择性地调制各种直径的纳米金刚石中 N 中心的强度在复杂材料系统中。这项工作首次表明了纳米颗粒直径如何影响 N 中心的寿命，从而直接影响使用 ODMR 实现背景自由成像时的对比度和信噪比，在存在干扰荧光团的情况下，对 N 纳米金刚石进行背景自由成像。这些结果提供了新的见解，将指导选择最佳的纳米颗粒尺寸和无背景成像和传感应用的方法，同时也提供了一个模型系统来探索环境中纳米材料的命运和迁移。
