Surface functionalization of nanoparticles for fabrication of size-tunable and electrochemically actuable nanostructured shell assembly*

Surface modification of quantum dots (QDs) is one of the most versatile methods of customizing their optical and electronic properties. Our goal is to leverage surface functionalization of CdSe/ZnS QDs for optimal directed assembly to be utilized in biological and biomedical cargo delivery systems. We have developed nano-assembled micro-shell structures composed of gold nanoparticles functionalized with custom-designed ligands¹ which allowed plasmonic actuation. Here, we focus on Bis(Imino)Pyradine (BIP) ligands which have improved thermal stability, optical properties, and biocompatibility of the shell structures, while allowing cargo release via electrochemical stimulation. In addition, the versatility of the BIP ligands have made it possible for us to tune the shell diameter from 200 nm to 1 micron, which vastly broadens the field of applications. In this study we present a systematic characterization of the QD surface chemistry to observe and understand correlations between QD diameter, ligand size and shell size.
1. Quint, M. T. et al. Plasmon-actuated nano-assembled microshells. Sci. Rep. 7, 17788 (2017).