Rapid self-healing and self-adhesive chitosan-based hydrogels by host-guest interaction and dynamic covalent bond as flexible sensor

A sensor used to monitor tissue deformation requires good flexibility, stretchability, self-adhesion, cytocompatibility, and antibacterial property. Here, we prepared hydrogel sensor based on O-carboxymethyl chitosan (O-CMCS) and poly(vinyl alcohol) (PVA) for monitoring human and organ motions. Based on the host-guest complexing of poly(beta-cyclodextrin) with diamantane, a cross-linker containing multiple aldehyde groups was prepared for cross-linking with O-CMCS through Schiff base linkages. Borax was used as the second cross-linker to cross-link PVA through dynamic borate ester bonds. Carbon nanotubes (CNTs) were added into the hydrogels to improve their electrical conductivity and mechanical properties. The obtained hydrogel exhibited rapid selfhealing ability with healing efficiency as high as 97%-103% (in 15 s), good adhesion to human skin and wet organ, good antibacterial property, cyto-compatibility, and stretchability. Furthermore, the hydrogel sensor can monitor the respiratory movement of porcine lungs and the beating of rat hearts.

Automated summary

A hydrogel sensor based on O-CMCS and PVA was prepared in this study, showing excellent mechanical properties and biocompatibility for monitoring human organ movements. Addition of carbon nanotubes improved the electrical conductivity and self-healing ability of the hydrogel.