De novo design of allochroic zwitterions

Zwitterionic materials and allochroic materials, as the two completely different materials, offer distinct properties and functions for different applications, where the former is well recognized as bio-inert materials with highly hydrophilic, antifouling, and biocompatible properties, while the latter is proven as stimuli-responsive discoloration materials with poor water solubility and high toxicity to cells. However, the development of zwitterionic, allochroic materials remains great challenging by integrating these oppositely properties into the same materials. Here, we designed and synthesized water-soluble, allochroic, and zwitterionic polymers of (pVPES) with built-in nonfouling and pH-responsive discoloration properties under in vitro and in vivo conditions. pVPES can serve as a versatile material platform for either self-polymerizing into different architectures (i.e., brushes, colloids, microgels, hydrogels,) or co-polymerization with other functional polymers to become different smart devices (i.e., colorimetric pollutant sensors, electrochromic smart windows, bilayer hydrogel actuators), all realizing the integration of antifouling and allochroic properties. More importantly, pVPES-based hydrogel patches enabled to not only accelerate wound healing of both chronic and acute wounds, but also distinguish chronic wounds from acute wounds in mice by color changes. This work opens new directions for the development of functional zwitterionic materials by integrating allochroic properties into inert materials for bio-optics applications.