A mechanically tough and ultra-swellable microneedle for acute gout arthritis

Acute gout arthritis (AGA) remains the fundamental research focus in the entire medical field. Hydrogel microneedles (HMNs) loaded with therapeutic molecules such as colchicine (Col) have been developed as a new tool for the management of AGA in a minimally invasive manner. However, the incompatible mechanical and swelling properties of HMNs limited the diffusion of the drug from the HMN system, which remains a challenge for practical use. Here, a mechanically tough (11.53 N per needle) and super-swelling (2708%) hydrogel microneedle (HMNs) composed of a uniform network structure was developed using a UV-responsive crosslinker through in situ photopolymerization for percutaneous delivery of Col. Such HMNs and Col loaded HMNs (Col-HMNs) present excellent biocompatibility. Moreover, Col-HMNs present considerable anti-inflammatory effects in vivo through down-regulated inflammatory responses such as related cytokines IL-1β, IL-6, and TNF-α. These results demonstrated that the mechanically tough and super-swelling HMNs could be a promising tool for effective Col delivery to relieve AGA.