Construction of Skin-Adaptable Slide-Ring Hydrogels Based on Bile Acids Derived Polyrotaxanes for Smart Wound Dressing

Slide-ring hydrogels (SR-Gel) feature mechano-adaptive networks with exceptional stretchability and skin-adaptability, ideal for smart dressing applications. However, current SR-Gel systems primarily rely on polyrotaxanes fabricated from poly(ethylene glycol) (PEG) and α-cyclodextrins (α-CDs), which typically possess an uncontrollable host-guest coverage ratio. It is therefore crucial to develop efficient construction strategies that enable the fabrication of diverse SR-Gels and broaden their scope and utility. Herein, we designed a polymerizable pseudo polyrotaxane with low host-guest coverage via precise molecular recognition between β-cyclodextrin (β-CD) and a bile-acid-derived guest polymer. This precursor was photopolymerized with zwitterionic sulfobetaine methacrylate and N - acryloyl glycinamide to construct a skin-adaptable SR-Gel. The sliding crosslinks provide enhanced chain mobility, endowing the hydrogel with high stretchability, excellent fatigue resistance, and the ability to adapt to wound deformation. Furthermore, levofloxacin-loaded ZIF-8 nanoparticles (ZIF-8@Levo) were incorporated to obtain a conductive composite hydrogel (SR-Gel/ZL), which was not only applied to treat bacterial infections, but could also stimulate and differentiate temperature, blood, and pressure, simultaneously. This work represents the first SR-Gel system constructed from a bile acid/β-CD polyrotaxane. Compared with the traditional PEG/α-CD system, the host-guest ratio can be precisely controlled, and the synthesis steps are simpler, providing a universal molecular model for the development of high-performance slide-ring materials.