We are exploring new biomimetic approaches to anchoring of nonfouling polymers onto biomedically relevant surfaces, with the goal of rendering implants/devices resistant to cell and protein adsorption. Paradoxically, this strategy also exploits the exceptional fouling characteristics of mussel adhesive protein mimics for surface immobilization of antifouling polymers (for more information on the composition and properties of mussel adhesive proteins, see our section on Mussel Adhesive Protein Mimetics). We anticipate that this approach may be broadly applied to medical implants and diagnostic devices, as well as numerous nonmedical applications in which minimization of surface fouling is desired. Obvious applications of these polymers include protein and cell-resistant surfaces for medical applications (biosensors, coagulation-resistant surfaces, etc.), however there is considerable potential use of this strategy for nonmedical applications as well. In fact, it is interesting to ponder the possible use of this mussel adhesive mimetic strategy for preparing nonfouling surfaces resistant to attachment of mussels, barnacles, and other classic marine biofouling organisms.

We recently discovered that the DOPA-PEG polymers we originally synthesized for our adhesive hydrogel project have exceptional nonadhesive/nonfouling properties as well. Exposure of a metal or metal oxide surface to a solution of DOPA-PEG polymer results in significantly reduced protein and cell attachment to the surface (Journal of the American Chemical Society, vol. 125, 2003, pp. 4253-4258). For example, cell attachment to a PEG-decapeptide modified surface was reduced by 97% compared to unmodified gold. Characterization of the modified surfaces suggested that the nonfouling polymer is anchored onto the surface by the DOPA containing peptide.

Ongoing studies include the investigation of DOPA peptide composition and length on cell and protein resistance, extension of this strategy for conferring fouling resistance to organic surfaces, incorporation of biological ligands and signaling molecules to control cell behavior at the modified surfaces, and the development of patterning strategies for patterning adhesive and non-adhesive regions of a surface. The protein resistance experiments involve a collaboration with Marcus Textor’s Biointerfaces Group at the Swiss Federal Institute of Technology in Zurich. Meanwhile, in a new collaboration with Prof. Annelise Barron, we are developing new peptide mimetic polymers for use in biofouling prevention.