Pioneering wound care solutions: triaxial wet-spun fibers with bioactive agents for chronic wounds, part II (controlled release and biological activity of the active agents)†

Abstract

The incidence of bacterial infections associated with chronic wounds (CWs) has increased in recent years. Thus, a triaxial wet-spun fibrous system (containing three layers) was produced for CW healing. The triaxial fibers were loaded with cinnamon leaf oil (CLO), endowed with high antibacterial, antioxidant and anti-inflammatory features, and an antimicrobial peptide –alanine–alanine–proline–valine (AAPV) – capable of regulating the activity of human neutrophil elastase (HNE; highly expressed during inflammatory processes). To overcome the characteristic high volatility of essential oils (EOs), CLO was loaded at the system's core and blended with polycaprolactone (PCL) which has excellent elasticity and tensile strength. The intermediate layer was composed of sodium alginate (SA) which has high hydration capacity and AAPV. Finally, the shell was made of cellulose acetate (CA), ensuring the system's structural integrity and providing a porous network for the controlled release of AAPV and CLO. This research was divided into two parts, with the present addressing the biological characterization of the system, namely the controlled release of bioactive agents, their antibacterial, antioxidant and cytocompatibility profiles and the peptide-loaded fiber ability to inhibit HNE activity. AAPV-loaded wet-spun fibers attained a sustained release of up to 55% during 24 h of incubation in physiological-like media, also presenting effective HNE inhibition (≈65%). Additionally, CLO-loaded fibers demonstrated a controlled release of up to ≈52% during 24 h of incubation in PBS, reaching higher antibacterial and antioxidant profiles in comparison with the unloaded fibers. Data confirmed the biological potential, safety and suitability of the proposed system for future applications in CW care.