Development and characterization of optical imaging probes

目前，有一个主要项目专注于功能化和表征荧光纳米金刚石： 我们正致力于功能化和表征氮空位中心荧光纳米金刚石（FND）用作多模态成像探针。这些是用于体内和体外跟踪和成像研究的有吸引力的荧光颗粒，因为它们是明亮的、不闪烁的荧光团，其在绿色（560 nm）中被激发并且在红色至远红色光谱（680-800 nm）中发射，与较短波长相比，其具有上级组织穿透和信噪比特性。此外，金刚石是惰性的，并且荧光由氮空位产生，因此核颗粒不含有机染料或其他可能有毒的材料，这些材料对于体内应用是有问题的。值得注意的是，FND可以小至10 nm，这对于生物相容性和清除也是有利的。我们已经建立了用于生物医学应用的功能化FND的方案。 我们最近发表的工作描述了用介孔聚多巴胺封装FND的方法，并证明了这种方法能够实现多种生物学应用，包括细胞成像，单分子水平的灵敏siRNA检测，以及增强化疗剂阿霉素的装载和细胞递送。 这项工作扩展了功能性表面改性方法，可用于继续开发FND作为生物成像探针。 除了它们显著的荧光特性之外，金刚石的高折射率使得纳米金刚石潜在地用作光学捕获探针。 我们与加拿大阿尔伯塔大学物理系的Michael伍德赛德教授合作，对FND的光学捕获进行了先前的演示。 在最近发表的一项研究中，我们证明了300 nm量级的纳米金刚石是优秀的光捕获探针，可以将光捕获测量的时间分辨率提高到微秒级，这比传统的聚苯乙烯或二氧化硅光捕获探针实现的时间分辨率有了大幅提高。

Currently, there is one overarching project focused on functionalizing and characterizing fluorescent nanodiamonds: We are working on functionalizing and characterizing nitrogen vacancy center fluorescent nanodiamonds (FNDs) for use as multi-modal imaging probes. These are attractive fluorescence particles for in vivo and in vitro tracking and imaging studies as they are bright, non-blinking fluorophores that are excited in the green (560 nm) and emit in the red to far-red spectrum (680-800 nm), which has superior tissue penetration and signal-to-noise characteristics compared with shorter wavelengths. Moreover, diamond is inert and the fluorescence arises from the nitrogen vacancy so the core particle contains no organic dyes or other potentially toxic material that would be problematic for in vivo applications. Remarkably, the FNDs can be as small as 10 nm, which is also advantageous for biocompatibility and clearing. We have established protocols to functionalize FNDs for biomedical applications. We recently published work describing methods to encapsulate FNDs with mesoporous polydopamine, and demonstrated that this approach enables diverse biological applications including cellular imaging, sensitive siRNA detection at the single-molecule level, and enhanced loading and cellular delivery of the chemotherapeutic agent Doxorubicin. This work extends the functional surface modification approaches available for continued development of FNDs as biological imaging probes. In addition to their remarkable fluorescence properties, the high index of refraction of diamond makes nanodiamonds potentially useful as optical trapping probes. We followed up previous demonstration of optical trapping of FNDs in collaborative work with Professor Michael Woodside in the department of Physics at the University of Alberta Canada. In a recently published study, we demonstrated that nanodiamonds on the order of 300 nm are excellent optical trapping probes that could increase the time resolution to the microsecond scale in optical trapping measurements, which is a substantial increase over the time-resolution achieved with conventional polystyrene or silica optical trapping probes.