Three-Dimensional, Bifunctional Microstructured Polymer Hydrogels Made from Polyzwitterions and Antimicrobial Polymers.

Biofilm-associated infections of medical devices are a global problem. For the prevention of such infections, biomaterial surfaces are chemically or topographically modified to slow down the initial stages of biofilm formation. In the bifunctional material here presented, chemical and topographical cues are combined, so that protein and bacterial adhesion as well as bacterial proliferation are effectively inhibited. Upon changes in the surface topography parameters and investigation of the effect of these changes on bioactivity, structure-property relationships are obtained. The target material is obtained by microcontact printing (μCP), a soft lithography method. The antimicrobial component, poly(oxanorbornene)-based synthetic mimics of an antimicrobial peptide (SMAMP), was printed onto a protein-repellent polysulfobetaine hydrogel, so that bifunctional 3D structured polymer surfaces with 1, 2, and 8.5 μm spacing are obtained. These surfaces are characterized with fluorescence microscopy, surface plasmon resonance spectroscopy, atomic force microscopy, and contact angle measurements. Biological studies show that the bifunctional surfaces with 1 and 2 μm spacing are 100% antimicrobially active against Escherichia coli and Staphylococcus aureus, 100% fibrinogen-repellent, and nontoxic to human gingival mucosal keratinocytes. At 8.5 μm spacing, the broad-band antimicrobial activity and the protein repellency are compromised, which indicates that this spacing is above the upper limit for effective simultaneous antimicrobial activity and protein repellency of polyzwitterionic-polycationic materials.