| dc.description.abstract | This work explores antibiotic-containing coatings constructed utilizing polyphosphazenes (PPz) and designed to release antibiotics only in the presence of bacteria. Specifically, polymer coatings of anionic PPzs with trifluoroethoxy as fluorinated groups and carboxylatophenoxy or sulfophenoxy as ionic groups were directly assembled with cationic antibiotics and compared. The effect of charge density, binding strength, and polymer fluorination degree on several film properties including growth, swelling, hydrophobicity, stability/pH response, mechanical adhesion, and antibacterial efficacy was determined. All PPzs enabled electrostatic layer-by-layer deposition with a wide range of cationic antibiotics, including Polymyxin B, Colistin, Gentamicin, and Neomycin. Sulfo-containing PPzs coatings exhibited more linear growth than carboxy-containing PPzs, while all types of PPz antibiotic coatings exhibited strong mechanical adhesion of the coating to the silicon wafer substrate. Wettability and swelling ratio of coatings in pH 7.5 PBS at 37 °C were shown to be dependent on the degree of fluorination and binding strength. The two types of coatings were designed to have drastically different response to pH lowering, which is usually associated with E. coli bacteria, with carboxy-containing PPzs being pH responsive and sulfo-containing PPzs resistant to pH change. Bacterial performance is dependent on the type of PPz but can prevented high colonization with bacteria with concentrations up to 107 CFU per cm2. Altogether, these findings show how the properties of coatings can be controlled by the composition of PPzs, which can lead to creating biocompatible self-defensive antibacterial coatings. | |
