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

## TL;DR

A new smart hydrogel for wound dressings was developed using bile acid and β-cyclodextrin, offering stretchability, infection control, and sensing abilities.

## Contribution

The first slide-ring hydrogel using bile acid/β-CD polyrotaxane with precise host-guest control and simplified synthesis.

## Key findings

- The hydrogel shows high stretchability and fatigue resistance due to sliding crosslinks.
- It integrates multi-signal sensing for temperature, blood, and pressure.
- The system enables pH-responsive antibacterial activity through levofloxacin-loaded ZIF-8 nanoparticles.

## Abstract

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 pseudopolyrotaxane 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.

A novel β‐cyclodextrin/bile acid‐based slide‐ring hydrogel was prepared via precise host–guest recognition and photopolymerization. This smart hydrogel dressing exhibited skin‐adaptive mechanical properties, pH‐responsive antibacterial activity, and integrated multi‐signal sensing (temperature, blood, and pressure) for advanced wound management.