Development of Metal-based Nanomaterials for Biomedical Applications

New synthetic advances in the control of nanoparticle size and shape along with the development of new surface modifications facilitates the growing use of nanomaterials in biomedical applications. Of particular interest are functional and biocompatible nanomaterials for sensing, imaging, and drug delivery. The goal of this research is to tailor the function of nanomaterials for biomedical applications by improving the biocompatibility of the systems.

Our work demonstrates both a bottom up and a post synthetic approach for incorporating stability, stealth, and biocompatibility to metal based nanoparticle systems. Two main nanomaterial projects are the focus of this dissertation. We first investigated the development of a green synthetic procedure to produce gold nanoparticles for biological imaging and sensing. The size and morphology of gold nanoparticles directly impact their optical properties, which are important for their function as imaging agents or their use in sensor systems. In this project, a synthetic route based on the natural process of biomineralization was developed, where a designed protein scaffold initiates the nucleation and subsequent growth of gold ions. To gain insight into controlling the size and morphology of the synthesized nanoparticles, interactions between the gold ions and the protein surface were studied along with the effect of ionic strength on interactions and then subsequent crystal growth. We are able to control the size and morphology of the gold nanoparticles by altering the concentration or identity of protein scaffold, salt, or reducing agent.

The second project involves the design and optimization of metal organic framework nanoparticles for an external stimulus triggered drug delivery system. This work demonstrates the advantages of using surface coatings for improved stability and functionalization. We show that the addition of a polyethylene glycol surface coating improved the colloidal stability and biocompatibility of the system. The nanoparticle was shown to successfully encapsulate a variety of small molecule cargo. This is the first report of photo-triggered degradation and subsequent release of the loaded cargo as a mechanism of stimuli-controlled drug delivery. Each of the aforementioned projects demonstrates the design, synthesis, and optimization of metal-based systems for use in biomedical applications.