The use of fluorescence microscopy to study fate and transport of nanoparticles in the environment can be limited by the presence of confounding background signals such as autofluorescence and scattered light. The unique spin-related luminescence properties of nitrogen vacancy (NV) centers in diamond nanoparticles (NVND) enable new types of imaging modalities such as selective imaging of nanoparticles in the presence of background fluorescence. These techniques make use of the fact that the spin properties, which affect the fluorescence of NV centers, can be modulated using applied magnetic or radio-frequency fields. This work presents the use magnetic fields to modulate the fluorescence of NVND for background-subtracted imaging of nanoparticles ingested by a model organism, C. elegans. With the addition of modest time-modulated magnetic fields from an inexpensive “hobby” electromagnet, the fluorescence of 40 nm NVND can be modulated by 10% in a widefield imaging configuration. Herein, differential magnetic imaging is used to image and to isolate the fluorescence arising from nanodiamond within the gut of the organism C. elegans. This method represents a promising approach to probing the uptake of nanoparticles by organisms and to assessing the movement and interactions of nanoparticles in biological systems.

中文翻译：

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使用磁感​​应荧光对比剂对复杂基质中金刚石纳米粒子的选择性成像

荧光显微镜在研究环境中纳米粒子的命运和运输方面的应用可能会受到背景信号（例如自发荧光和散射光）混杂的限制。金刚石纳米粒子（NVND）中氮空位（NV）中心的独特的自旋相关发光特性可实现新型的成像方式，例如在存在背景荧光的情况下对纳米粒子进行选择性成像。这些技术利用以下事实：可以使用施加的磁场或射频场来调制影响NV中心荧光的自旋特性。这项工作提出了利用磁场来调制NVND荧光的方法，以用于模型生物（秀丽隐杆线虫）摄入的纳米颗粒的背景扣除成像。。通过从廉价的“爱好”电磁铁中添加适度的时间调制磁场，可以在宽场成像配置中将40 nm NVND的荧光调制10％。在本文中，使用差分磁成像来成像并分离由秀丽隐杆线虫的肠内的纳米金刚石产生的荧光。该方法代表了一种有前途的方法，用于探测生物对纳米颗粒的吸收并评估纳米颗粒在生物系统中的运动和相互作用。