Gold Nanorods Function as Near-Infrared Light-Activated Microheaters for <i>In Situ</i> Curing of Injectable Hydrogel Therapies

Abstract

Injectable hydrogels have gained popularity as an attractive solution for wound dressing therapies due to their ability to conform to irregular wound sites and in situ polymerization. However, the harmful effects of ultraviolet (UV) exposure limit the applicability of photocuring methods, while thermal curing is limited by its high-temperature requirement and nonselective curing. To address these limitations, we present a method of curing hydrogels in situ by incorporating gold nanorods (AuNRs) as microheaters to initiate and regulate local thermal polymerization of the hydrogel upon exposure to near-infrared (NIR) light. In the present method, the well-dispersed AuNRs in the hydrogel presolution enable millions of microheaters to heat up the solution, resulting in a faster kinetic rate and higher polymerization conversion compared to the traditional thermal curing method. Moreover, the NIR light-initiated curing process leads to a more uniform microstructure and improved mechanical performance of hydrogels. This in situ, fast, and selective curing method presents a superior alternative to traditional curing methods and is an ideal choice for wound dressing therapies and other biomedical applications.