Coated electrospun bioactive wound dressings: Mechanical properties and ability to control lesion microenvironment

Advanced wound dressings capable of interacting with lesions and changing the wound microenvironment to improve healing are promising to increase the therapeutic efficacy of this class of biomaterials. Aiming at the production of bioactive wound dressings with the ability to control the wound microenvironment, biomaterials of three different chemical compositions, but with the same architecture, were produced and compared. Electrospinning was employed to build up a biomimetic extracellular matrix (ECM) layer consisting of poly(caprolactone) (PCL), 50/50 dl-lactide/glycolide copolymer (PDLG) and poly(l-lactide) (PLLA). As a post-treatment to broaden the bioactivity of the dressings, an alginate coating was applied to sheathe and functionalize the surface of the hydrophobic electrospun wound dressings, in combination with the extract of the plant Arrabidaea chica Verlot, known for its anti-inflammatory and healing promotion properties. Wettable bioactive structures capable to interact with media simulating lesion microenvironments, with tensile strength and elongation at break ranging respectively from 155 to 273 MPa and from 0.94 to 1.39% were obtained. In simulated exudative microenvironment, water vapor transmission rate (WVTR) values around 700 g/m²/day were observed, while water vapor permeability rates (WVPR) reached about 300 g/m²/day. In simulated dehydrated microenvironment, values of WVTR around 200 g/m²/day and WVPR around 175 g/m²/day were attained.