Zwitterionic polymers and hydrogels for antibiofouling applications in implantable devices

Biofouling, generally initiated by non-specific adsorption of cells, proteins and microorganisms, is a persistent challenge in a wide range of applications, including implantable biomedical devices, biosensors, surgical and protective tools in hospitals, food storage and packages, water purification membranes, marine and industrial surfaces. Surfaces that resist the non-specific adsorption of proteins and microbes are also important in catheters, prosthetic devices and contact lenses, in immunological assays like enzyme-linked immunosorbent assays (ELISA), in materials for cell culture, and in drug delivery devices. Biofouling from cell or bacteria adhesion on implanted biomedical devices can cause infection and complications. The direct cost of such fouling has exceeded $3 billion annually in the United States alone. Significant effort is directed towards designing important class of robust ultralow-fouling zwitterionic polymer and hydrogel biomaterials with higher in vivo stability, prevention of bacterial adhesion, and protein adsorption resistance. This manuscript provides a critical review of such zwitterionic materials carrying permanent positive and negative charges, but displaying an overall charge neutrality. The concepts reviewed here include the synthesis, coating, functionalizations, and in vitro and in vivo applications of zwitterionic materials for antibiofouling applications.