Peptide Self-assembly Into Antifouling Nanoparticles

Biofouling is the undesirable accumulation of microorganisms and their by-products on a surface. It has become a serious problem in many areas of life. For example, biofouling by bacteria leads to hospital-acquired infections that increase the rate of mortality. Another example is biofouling by marine mussels that leads to bio-corrosion of marine devices. One solution to the problem is to avoid biofouling by coating the surfaces with antifouling materials that can prevent the adsorption of foulants. In this context, we designed and synthesized three small peptides containing catechol groups for adhesion and aromatic residues to direct self-assembly of the peptide. In addition, the peptide aromatic resides are modified with fluorine atoms to generate antifouling properties. We observed that the peptides self-assemble on titanium substrates into either nanospheres, nanofibers or fibrous network depending on the C-terminus residue of the sequence. The peptide with C-terminus DOPA forms nanospheres and the peptides with tyrosine or phenylalanine at the C-terminus form straight fibres or fibrous network respectively. Adhesion measurements using titanium coated AFM tip on the peptide coatings revealed that the nanofibers adhere strongly to the surface. In addition, antifouling assays with E. coli clearly showed a 90% reduction in bacterial adsorption to the coated surfaces. We, therefore, suggest that the nanofibrous peptide-based assemblies can serve as an antifouling coating for metal surfaces.