De novo design of functional zwitterionic biomimetic material for immunomodulation.

Superhydrophilic zwitterionic polymers are a class of nonfouling materials capable of effectively resisting any nonspecific interactions with biological systems. We designed here a functional zwitterionic polymer that achieves a trade-off between nonspecific interactions providing the nonfouling property and a specific interaction for bioactive functionality. Built from phosphoserine, an immune-signaling molecule in nature, this zwitterionic polymer exhibits both nonfouling and immunomodulatory properties. Its conjugation to uricase is shown to proactively eradicate all unwanted immune response, outperforming the zwitterionic polymers. On the other hand, this polymer could significantly prolong the half-life of protein drugs in vivo, overcoming the innate drawback of phosphoserine in inducing accelerated clearance. Our demonstration of a nonfouling zwitterionic material with built-in immunomodulatory functionality provides new insights into the fundamental design of biomaterials, as well as far-reaching implications for broad applications such as drug delivery, implants, and cell therapy.