Development and characterization of optical imaging probes

National Heart, Lung, And Blood Institute

Investigators

Linked publications, trials & patents

Abstract

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 far red spectrum (680 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 5 nm, which is also advantageous for biocompatibility and clearing. We have establish protocols to functionalize FNDs for biomedical applications. We have also been developing novel applications for the FNDs and this reporting period we demonstrated an application in forensic science; developing the nanodiamonds as biocompatible multimodal probes for the development and detection of latent fingerprints. Work is continuing to expand the functionalization of the FNDs to produce multi-modal particles that can serves as both targeted fluorescent nanoparticles and drug delivery agents. Using a recently developed micro-mirror TIRF microscope combined with a magnetic tweezers, we have developed a method to simultaneously determine the size and brightness of individual FNDs in a massively parallel measurement. This is an important measurement for the characterization of FNDs that has previously been exceedingly low throughput. This new approach allow affords us the opportunity to simultaneously measure the magnetic response of individual FNDs as a function of their size and brightness.