Self-Assembled Switchable Antimicrobial Polymer Thin Film Coating

Abstract

Present project aims a molecular fabrication approach to study the behavior of fouling organisms on planar surfaces at specifically controlled pH for the polymeric thin films coatings fabricated by electrostatic layer-by-layer (LbL) assembly methods. Poly(acrylic acid) (PAA, a weak polyanion) and poly(diallyldimethylammonium chloride) (PDADMAC, a strong polycation) were used to fabricate the bulk films. The weak Poly(allylamine hydrochloride) (PAH) was used as a top layer in bacterial adhesive thin films. Surface charge tuning was accomplished by regulating the level of ionization of the weak polyelectrolytes at different pH values and subsequent manipulation of the amount of polyelectrolyte deposited in the one preceding the last and last layers, respectively. The prepared films were investigated for their antimicrobial and bacterial adhesive surface characteristics. The fouling behavior of bacteria on the LbL films with almost comparable hydrophilicity and roughness but varying surface charge densities was studied. Antimicrobial activity of coated glass slides was evaluated against Escherichia coli (E. coli, ATCC# 8739) and Staphylococcus aureus (S. aureus, ATTC# 6538). The switchable thin film coatings developed allows achieving optimal microbial growth both in terms of repelling and adhesion performances at the precise pH values of the environment. The surface characteristics of the foulants as well as the bacterial adhesive thin films can be used to switchably attach or repel and detect control concentration of bacterial strains.