Nitrogen enriched C:H:N:O thin films for improved antibiotics doping

In this study we investigate the ability of RF magnetron sputtered nylon 6,6 films (C:H:N:O) to store and release two model antibiotics, ampicillin and ciprofloxacin, that differ significantly in their chemical structure. We demonstrate that the addition of nitrogen to the deposition process leads to a substantial enhancement in the abundance of nitrogen-containing functional groups in the resulting coatings as well as to the significant changes in their swelling and dissolution. These variations were found to result in different impregnation and release capabilities of the produced coatings: an almost 5 times higher amount of released antibiotics was observed for the samples prepared in nitrogen-rich atmosphere when compared to films deposited in pure argon. It was also found that the amount of released antibiotics strongly depends on the natural character of the antibiotics used. However, it is demonstrated that minimum inhibitory concentrations against S. epidermidis and E. coli can be exceeded for both antibiotics.