Combining chemistry and topography to fight biofilm formation: Fabrication of micropatterned surfaces with a peptide-based coating.

This paper describes the fabrication of antifouling surfaces by the combination of topography and peptide chemistry. The topography of the surface mimics the skin of the shark that can resist biofouling by having a certain microtopography. A peptide-based coating that resists fouling self-assembles on these surfaces. In biofilm formation assays, performed under static conditions, the resulting combination (micropattern with peptide coating) has superior antifouling properties against the Gram-negative and Gram-positive strains tested (Escherichia coli and Staphylococcus epidermidis, respectively) when compared to both micropatterned and peptide-coated surfaces. The same behavior was observed in dynamic assays performed in a parallel plate flow chamber (PPFC) setup, where E. coli could not attach to the micropatterned surface coated with peptide during the 30 min of initial adhesion. These assays, mimicking physiological shear stress conditions, suggest that the peptide-coated surface with micropatterned topography may be promising in reducing adhesion and subsequent biofilm formation in biomedical devices such as urinary catheters and stents, and cardiovascular, dental and orthopedic implants.

The effect of end-group substitution on surface self-assembly of peptides.

Biofouling, the undesirable accumulation of organisms onto surfaces, affects many areas including health, water, and energy. We previously designed a tripeptide that self-assembles into a coating that prevents biofouling. The peptide comprises three amino acids: DOPA, which allows its adhesion to the surface, and two fluorinated phenylalanine residues that direct its self-assembly into a coating and acquire it with antifouling properties. This short peptide has an ester group at its C-terminus. To examine the importance of this end group for the self-assembly and antifouling properties of the peptide, we synthesized and characterized tripeptides with different end groups (ester, amide, or carboxylic group). Our results indicate that different groups at the C-terminus of the peptide can lead to a change in the peptide assembly on the surface and its adsorption process. However, this change only affects the antifouling properties of the coating toward Gram-positive bacteria (Staphylococcus epidermidis), whereas Gram-negative bacteria (Escherichia coli) are not affected.

Resisting Bacteria and Attracting Cells: Spontaneous Formation of a Bifunctional Peptide-Based Coating by On-Surface Assembly Approach.

Due to extension of life expectancy, millions of people suffer nowadays from bone and dental malfunctions that can only be treated by different types of implants. However, these implants tend to fail due to bacterial infection and lack of integration with the remaining tissue. Here, we demonstrate a new concept in which we use specifically designed peptides, in a "Lego-like" manner to endow multiple preprogrammed functions. We developed a bifunctional peptide-based coating that simultaneously rejects the adhesion of infecting bacteria and attracts cells that build the new connecting tissue. The peptide design contains fluorinated phenylalanine that mediates the self-assembly of the peptide into a coating that resists bacterial adhesion. It also includes an Arg-Gly-Asp (RGD) motif that attracts mammalian cells. The whole compound is attached to the surface using a third unit, the amino acid 3,4-dihydroxyphenylalanine (DOPA). This novel, yet very simple approach is significantly advantageous for practical use and synthesis. More importantly, this peptide design can serve as a general platform for generating functional coatings.