Here, pH and temperature are explored as stimuli to control antibiotic release from self-defensive layer-by-layer films, and the antibacterial performance of these films is evaluated. “Smart” biomedical coatings, which release antibiotics only when and where needed, can help minimize the development of bacterial antibiotic resistance and thus are highly desirable. First, pH-responsive self-defensive coatings are made as chemically crosslinked hydrogel-like, ultrathin layer-by-layer coatings. The coatings are capable of hosting and releasing antibiotics in response to bacterial presence. The use of pH-sensitive SNARF-1 fluorescent label attached to these hydrogels enabled imaging of local acidification induced by adhering Staphylococcus aureus and Escherichia coli by confocal laser scanning microscopy. The ability of pH-responsive coatings to release antibiotics in response to this acidification is investigated. Furthermore, temperature is explored as another physiologically relevant trigger to release antibiotics from self-defensive films. To that end, temperature-responsive block copolymer micelles are assembled within layer-by-layer coatings. A model compound and an antibiotic are shown to be entrapped by these micelles and to be released from the coatings upon prompting from a temperature stimulus. The coatings can be stimulated multiple times to trigger release at the desired time points. The temperature-triggered antibacterial activity of the antibiotic-loaded coatings is demonstrated with Staphylococcus aureus. Coatings such as these, which can selectively release cargo in response to a pH- or temperature stimulus, can be used with biomedical implants to prevent bacterial infection.

pH- and temperature-triggered self-defensive antibacterial layer-by-layer coatings

254th National Meeting (2017)

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