An important challenge in many applications is the prevention of unwanted nonspecific biomolecular and microorganism attachment on surfaces. To address this challenge, our goals are twofold. First, we strive to provide a fundamental understanding of nonfouling mechanisms at the molecular level. Second, we aim to develop biocompatible materials based on the molecular principles learned. As a result, we have shown that zwitterionic materials and surfaces are highly resistant to nonspecific protein adsorption and microorganism attachment from complex media.

In this talk, in addition to design principles, I will discuss the application of zwitterionic material to implants, stem cell cultures for controlled preservation/expansion/differentiation, medical devices and drug delivery carriers. With zwitterionic coatings, hydrogels or nanoparticles, results show no capsule formation upon subcutaneous implantation in mice for one year, expansion of hematopoietic stem and progenitor cells (HSPCs) without differentiation, no anti-coagulants needed for artificial lungs in sheep, and no antibodies generated against zwitterionic polymers. Currently, we are performing a fundamental study of material interactions with the immune system, developing immunomodulatory materials and safe/organ-targeting delivery carriers and translating our biomaterials to applications ranging from immunotherapy and vaccine to regenerative medicine.