(604b) Hybrid siRNA/Polymer/Gold Nanoparticle Theragnostics for Multi-Modal Optical Imaging with Simultaneous Gene Silencing

Developing theragnostics agents, which can diagnose abnormal lesions with molecular resolutions while simultaneously converting themselves to become activated therapeutic agents in the pinpointed area, has been a major thrust in medicine, particularly for cancer diagnosis and therapy. Gold nanoparticles (Au NPs) have been intensively explored as a promising contrast agent for optical sensor/imaging, due to their unique optical properties that can be easily tuned by changing their sizes/morphology. In this study, siRNA/polymer polyplexes were shelled by Au NPs, followed by PEGylation. It was hypothesized that the immobilized PEGylated Au NPs generate multiple opto-physical property changes, as well as activating the polyplexes for enhanced cellular uptake, in a tumor area. Results demonstrated 1) the size of the resulting nanoparticles decreased as confirmed by dynamic light scattering (DLS) and TEM, 2) Au NPs resulted in multi optical signal changes (e.g., significantly reduced scattering intensity, increased variance of Doppler frequency, and blue-shifted UV absorbance), and 3) the polyplex core silenced cellular gene expression, upon receiving cancer-specific stimulus. This talk will present 1) rationales in designing novel nanomaterials as dual functional contrast/therapeutic agents (theragnostics), 2) synthesis and characterization of the novel theragnostics, and 3) combined optical imaging and gene silencing in vitro.