TAILORING THE NANOSTRUCTURE OF MICELLAR PLURONIC HYDROGELS FOR NITRIC OXIDE DELIVERY

Nitric oxide (NO) is an endogenous signaling molecule involved in numerous physiological and pathophysiological processes. Due to its plethora of biological actions, NO administration from exogenous sources has been explored in various biomedical applications, such as the acceleration of wound healing, the enhancement of skin blood flow, and the reduction of inflammation and pain. For these purposes, various polymeric biomaterials have been used as matrices for local NO delivery. In our research line, focused on the development of NO-releasing biomaterials, micellar hydrogels of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymers of trade name Pluronic, have occupied a special place. In an aqueous medium, Pluronic molecules self-organize into nano-sized micelles. The micelles, in turn, organize into ordered packing structures, forming physical hydrogels. In this talk, I will show how we have used Pluronic hydrogels to incorporate NO donors into the intermicellar space and how the hydrophobic PPO cores of the micelles may serve as a reservoir for the accumulation of NO, modulating its release. I will also show how we have functionalized the chain ends of the PPO blocks of Pluronics with SNO groups, transforming the micelles into NO-releasing nanostructures, and with vinyl groups, causing the micelles to cross-link upon irradiation with visible light. Finally, I will show how the ordering of the micellar nanostructures can be characterized by SAXS and visualized by CryoTEM and how we have used the photocrosslinkable Pluronic hydrogels for the 3D printing of NO-releasing vascular constructs.