A facile strategy for fine-tuning the drug release efficacy of poly-L-lactic acid-polycaprolactone coatings by liquid flame spray.

The diversity of medical application scenarios demands fine-tuning of drug release profiles for better patient care. Here we report a facile strategy to construct composite coatings as universal drug delivery systems with tunable release efficacy. A poly-L-lactic acid (PLLA)-polycaprolactone (PCL) coating was fabricated by liquid flame spray and its performance was verified by loading chloramphenicol (CAM) as bactericidal component. Physiochemical analyses revealed the homogeneity of chemistry and integrity of functional groups of the composite coatings. Release of CAM was enhanced by the increase of the PCL content in the composite coatings, showing a controllable manner. Kinetics analysis suggested the release mechanism of Korsmeyer-Peppas model for both the PLLA-CAM and the PCL-CAM coatings, and the release regime for the PLLA-PCL composite coatings transited from the Higuchi model to the Korsmeyer-Peppas model when the PCL content increased from 30 % to 70 %. Further antibacterial testing revealed tailorable antibacterial activity of the coatings against both Escherichia coli and Staphylococcus aureus. Regulating the release of the drug CAM through altering PCL content in the PLLA-PCL coating would give inspiring insight into green fabrication of polymeric coatings with tunable drug release for versatile applications. [Display omitted] • The PLLA-PCL-CAM composite coating was facilely deposited on the 316 L substrate with liquid flame spray. • The morphological, chemical and antibacterial properties of the PLLA-PCL-CAM composite coating were investigated. • The drug release efficacy and antibacterial effect of the composite coating was well tunable with the ratio of PLLA and PCL. [ABSTRACT FROM AUTHOR]