title: Bacterial protease triggered release of biocides from microspheres with an oily core.
abstract: This study deals with controlled release of drugs to a Staphylococcus aureus infected site from microspheres with an oily core and a polymeric shell. The intended use of the microspheres is for chronic wounds and the microspheres may be administered in the form of a wash liquid or incorporated in a gel. Chronic wounds often carry infection, and the use of microspheres with drug release triggered by the bacterial infection is therefore of interest. A lipophilic drug or a model of the drug was dissolved in an oil and the oil phase was dispersed into an o/w emulsion. A nanofilm shell was then assembled around the oil droplets with the layer-by-layer technique using the two biodegradable polypeptides anionic poly-L-glutamic acid (PLGA) and cationic poly-L-lysine (PLL). Since S. aureus exudes proteases such as glutamyl endopeptidase (V8) during colonization and infection, its substrate specificity was key when assembling the nanofilm. Since V8 is known to be substrate specific to the Glu-X bond, PLGA was chosen as the terminating layer of the nanofilm. Crosslinking the nanofilm after assembly lead to increased stability of the microspheres. It was shown that in a non-infectious environment, i.e. when a human wound enzyme, HNE (human neutrophile elastase), was present, the microspheres remained intact. The staphylococcal protease V8, on the other hand, readily catalyzed degradation of the microspheres, thus releasing the drug when triggered by the infectious environment.
authors: Chalmers University of Technology, Chemical and Biological Engineering, Applied Surface Chemistry, Gothenburg, Sweden; Mölnlycke Health Care, Gothenburg, Sweden; SuMo Biomaterials, VINN Excellence Centre, Chalmers University of Technology, Gothenburg, Sweden. Electronic address: marina.craig@chalmers.se.
authors: Marina
authors: M
authors: Craig
authors: Chalmers University of Technology, Chemical and Biological Engineering, Applied Surface Chemistry, Gothenburg, Sweden.
authors: Mona
authors: M
authors: Amiri
authors: Chalmers University of Technology, Chemical and Biological Engineering, Applied Surface Chemistry, Gothenburg, Sweden; SuMo Biomaterials, VINN Excellence Centre, Chalmers University of Technology, Gothenburg, Sweden.
authors: Krister
authors: K
authors: Holmberg
mesh_terms: D000473:Alkanes / Q000737:chemistry; D001622:Betaine / Q000031:analogs & derivatives / Q000737:chemistry; D004202:Disinfectants / Q000494:pharmacology*; D006801:Humans; D019344:Lactic Acid / Q000737:chemistry; D019272:Leukocyte Elastase / Q000378:metabolism; D008863:Microspheres; D009821:Oils / Q000737:chemistry*; D010078:Oxazines / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism*; D011091:Polyesters; D011100:Polyglycolic Acid / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry; D012015:Reference Standards; D013211:Staphylococcus aureus / Q000201:enzymology*; D055672:Static Electricity; D014867:Water / Q000737:chemistry
chemical_list: D000473:Alkanes; D004202:Disinfectants; D009821:Oils; D010078:Oxazines; D011091:Polyesters; D011108:Polymers; C518257:decyl betainate; D014867:Water; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D001622:Betaine; C033616:poly(lactide); D010447:Peptide Hydrolases; D019272:Leukocyte Elastase; C044808:nile red
keywords: Controlled release; Hydrophobic drug; Microsphere; Nanofilm; Staphylococcus aureus; o/w emulsion