Tuning the stiffness of surfaces by assembling genetically engineered polypeptides with tailored amino acid sequence

Abstract

We introduce elastin-like recombinamers (ELRs) as polypeptides with precise amino acid positioning to generate polypeptide coatings with tunable rigidity. Two ELRs are used: V84- ELR, a hydrophobic monoblock, and EI-ELR, an amphiphilic diblock. Both were modified with the amine-reactive tetrakis (hydroxymethyl) phosphonium chloride compound. We evaluated the affinity, the conformation, and the dissipative behavior of ELRs assembled on alkanethiol selfassembled coatings by quartz crystal microbalance with dissipation monitoring, multi-parametric surface plasmon resonance, and atomic force microscopy. The thickness of the polypeptide coatings showcase the preferential affinity of ELRs to NH2 and CH3 terminated surfaces. We demonstrate that V84-ELR strongly bonded to the substrate and reorganizes into an extended and more hydrated layer as the adsorbed amount increases, whereas EI-ELR has a less dissipative behavior. The results suggest that ELR adsorption depends on the amino acid sequence and the substrate chemistry, ultimately influencing the stiffness of the polypeptide coatings.