Construction of a biomimetic zwitterionic interface for monitoring cell proliferation and apoptosis.

A new zwitterionic monolayer film of sulfobetaine was constructed by grafting novelly designed N,N-dimethyl (beta-hydroxyethyloxyethyl) ammonium propanesulfonate (DHAPS) to hydroxyl groups of glass in the presence of hexamethylene diisocyanate (HDI) as a coupling agent and dibutyltin dilaurate (DBTDL) as a catalyst. Experiments of blood adhesion proved that the zwitterionic film possessed excellent hydrophilicity and very good biocompatibility and provided an appropriate biomimetic interface for adhesion and proliferation of cells. Thus, the monitoring of the cell proliferation and apoptotic processes on the zwitterionic surface during an incubation process was achieved, using different techniques, such as electrochemical impedance spectroscopy, scanning electron microscopy, flow cytometric assay, and Trypan blue staining. K562 leukemia cells, as a model, cultured in vitro on the zwitterionic surface kept their viability for 5 days and remained healthy and undifferentiated, indicating that the zwitterionic surface did not have a deleterious effect on cell growth in normal conditions. Thus, this man-made interface would be applicable to the growth of cells and the study of biomaterial-cell interaction and has potential applications in medicine and cytobiology.