Metal-Polymer Composites as Externally-Controlled

Intelligent Therapeutic Systems

Martin Gran

Delivery of therapeutics via externally-triggered intelligent nanocarriers can increase the quality of life of patients by controlling the time and location of delivery, thereby lowering systemic doses and related side effects. The metal-polymer nanocomposites composed of a metal core and a surrounding temperature-sensitive polymer layer can be triggered to release encapsulated therapeutics upon exposure to an external light source. Metal nanoparticle or nanoshell cores can be tuned to absorb light at wavelengths ranging from visible to near-infrared. Absorbed light is converted to heat, inducing a size transition in the polymer layer causing encapsulated agents to be released.

Gold nanoparticles have been incorporated within an interpenetrating polymer network (IPN) composed of poly(acrylic acid) and poly(acrylamide). The nanocomposites are synthesized using a two-step water in oil emulsion polymerization with a cyclohexane continuous phase, where two aqueous premixes are added and reacted separately, the first premix containing acrylamide, and the second acrylic acid. Gold nanoparticles are added with the first aqueous premix and incorporated in the aqueous droplet phase. Additional temperature responsive polymers continue to be investigated for use in the system and future work includes the addition of targeting ligands and studies of the biocompatibility of the nanocomposite systems.