Polymeric Nanosensors and Nanozymes for Drug Delivery

Polydiacetylenes (PDAs) are a class of conjugated polymers with unique optical properties that make them excellent materials for the construction of colorimetric sensors. Diacetylene monomers polymerize when exposed to 254 nm UV light to form alternating ene-yne polymer chains. Polymerization typically yields blue-phase PDAs with a characteristic absorption peak at ∼640 nm. Chemical and biological recognition events can induce a blue-to-red color transition of PDA, which can be easily detected by the naked eye. This talk will describe examples of PDA-based sensors to enable low-cost, easy monitoring of food spoilage without the need of specialized equipment. The PDA sensors will provide a real time indication of food quality, to complement the function of traditional date marking tools.

I will also provide an overview of our research in nitric oxide (NO) delivery technology. NO is a potent biological molecule that contributes to a wide spectrum of physiological systems, including the cardiovascular, immune, and central nervous system. However, NO delivery technology remains severely limited due to its short half-life and limited diffusion distance in human tissues. Current strategies for NO delivery focus on the encapsulation of NO donors into biomaterials or an enzyme-prodrug therapy approach. The former is limited by the finite pool of NO donors available, while the latter is challenged by the inherent low stability of natural enzymes. Enzyme mimics are attractive substitutes for their natural counterparts in diverse biomedical applications because they have excellent stability against biological degradation compared with natural enzymes. In this work, we present nanoparticles with innate enzymatic activities that catalytically decompose endogenous and exogenous NO donors to generate NO to inhibit cancer cell proliferation and to disperse bacterial biofilms.