Temperature-Controlled Antimicrobial Release from Poly(diethylene glycol methylether methacrylate)-Functionalized Bottleneck-Structured Porous Silicon for the Inhibition of Bacterial Growth

Bacterial infections in wounds slow down the healing process and lead to increased morbidity in affected patients. Polymer coatings on porous membranes were investigated, which facilitate the in situ detection and treatment of, e.g., Escherichia coli and Staphylococcus aureus infections. The theranostic approach relies on the thermoresponsive polymer poly(diethylene glycol methylether methacrylate) (PDEGMA). The increase of the wound temperature due to infection is targeted in this proof of concept study for triggering the release of the fluorescent antibiotic levofloxacin from bottle-shaped porous silicon (pSi) membranes capped with PDEGMA brushes. Below their lower critical solution temperature (LCST) the PDEGMA brushes are expanded and the levofloxacin release is significantly retarded. By contrast, above the LCST the PDEGMA brushes collapse and levofloxacin is released rapidly, which is detectable in solution owing to its fluorescence properties. The concomitant inhibition of bacterial growth agrees favorably with the drug release determined by fluorescence spectroscopy.