Symposium NM05: Functional Nanoparticle Materials - Synthesis, Property and Applications

Pietro Aprà, University of Torino

Late News: Fluorescence Enhancement and Functionalization of Nanodiamonds for Optically Trackable Drug Delivery

Written by Jessalyn Hui Ying Low

In the field of drug delivery, targeted drug delivery is often favored to enhance therapeutic efficacy and reduce off-target side effects. For this, a range of nanoparticle-based systems have been developed, with nanodiamonds as a promising platform. Importantly, nanodiamonds possess highly photostable fluorescence properties, due to the presence of optically active defects, also known as nitrogen vacancy (NV) color centers. In this talk, Pietro Aprà presents his research work on the design of diamond-based drug delivery systems, integrating the concepts of drug delivery and fluorescence. This aims to achieve targeted drug delivery, while also being able to optically track the nanoparticles.

One important aspect in the design of such nanoparticles is fluorescence enhancement. This can be achieved by optimizing the chemical-physical processing of the nanodiamonds. Aprà showed that through annealing, etching, ion implantation, and second annealing, fluorescence intensity increased by about 800 times as compared to untreated nanodiamonds. The ion implantation step is key to creating more NV centers, but must be accompanied by annealing to rearrange the crystal lattice to a more energetically stable configuration and allow for NV coupling and fluorescence activation.

To achieve targeted delivery, these nanodiamonds were also then functionalized with cetuximab, a monoclonal antibody specific for epidermal growth factor receptor (EGFR) that is overexpressed in colorectal cancer cells. In vitro studies showed that the functionalized nanoparticles were successfully internalized, with fluorescence signal observed. These results highlight the great potential of using nanodiamonds to achieve integrated drug delivery and biolabeling capabilities.