Biodegradable Nanofilms on Microcapsules for Controlled Release of Drugs to Infected Chronic Wounds

Bacteria-triggered degradation of nanofilm shells for release of antimicrobial agents

“…Both microcapsules were also exposed to the natural wound enzyme, HNE, overnight. In one of our previous studies we showed that nanofilms composed of PAH and PLGA exposed to HNE did not degrade, while V8 destroyed the microcapsule structure and released the model drug [38]. Also the (HA/PLL) 3 nanofilm seemed relatively unaffected by the human wound protease, see Figure 4a.…”

“…The enzymatic degradation of the microcapsules was not only monitored visually, but the loss of fluorescense was also quantified by CLSM as loss in intensity. It is known from a previous study [38] that the substrate specific V8 from Staphylococcus aureus degrades a PLGA layer, causing rupture of the (PAH/PLGA) 3 nanofilm, hence releasing the model drug (FITC-dextran). In this work we have now also quantified the loss of fluorescense in the (PAH/PLGA) 3 microcapsules as loss in intensity.…”

“…The nanofilm responding to Pseudomonas aeruginosa exoproducts consisted of hyaluronic acid (HA), MW ≈3,8 MDa (Bohus BioTech, Sweden), and poly-L-lysine (PLL), MW 84 kDa (Alamanda Polymers, USA). The preparation of PAH/PLGA nanofilms (polyallylamine hydrochloride/poly-L-glutamic acid) responding to the Staphylococcus aureus infection is described in a previous study [38]. The buffer used was 0.1 mM Tris-HCl (Sigma Aldrich, Sweden) with 0.15 M NaCl (Sigma Aldrich, Sweden).…”

“…A nanofilm that was readily degraded by the chosen exoproducts was used as shell of hollow microcapsules, which contained a model drug. Additionally, our group's previous study concerning exoproducts from Staphylococcus aureus degrading a specific nanofilm [38] has been extended in this communication. LbL films with antibacterial activity [39,40], studies of antimicrobial and non-biodegradable microcapsules [41] and liposomal vesicles for diagnostics [42] have previously been reported in the literature.…”

Modeling of in vitro drug release from polymeric microparticle carriers

“…The main goals of microencapsulation are: 1) protection of bioactive substances from unfavorable environmental factors (e.g., oxidation, hydrolysis, light or heat) or against the biological environment (e.g., pH, enzymes, hydrolysis, proteolysis, endocytosis); 2) overcoming certain production challenges, including poor flowability of powders, incorporation of volatile and/or liquid ingredients into a solid dosage form, drug incompatibility, and unpleasant taste, odor or color of the drug substance; 3) increasing drug retention time on the skin or the mucous membranes; 4) localizing drug delivery and/or achievement of a prolonged drug release in order to enhance patient compliance and minimize risks of side effects (1)(2)(3)(4). Among all microencapsulation carriers, polymer microparticles based on various synthetic and semi-synthetic polymers and/or natural macromolecules have the greatest potential to protect and deliver drugs in a controllable way (5)(6)(7)(8). In recent years, biocompatible microparticles based on biodegradable polymers and biopolymers, including polypeptides and polysaccharides, have received widespread attention as carriers for controlled drug release (Table I).…”