Fiber-Hydrogel Sandwich-Like Composites with Improved Antimicrobial Protection

Most conventional dressings present a passive action against microorganisms. Here, a multifunctional sandwich-like system was proposed and examined for its potential in fighting CW infections. The scaffolding system was made of three layers: (outer) fibrous mat of polycaprolactone (PCL) working as a barrier for preventing other microorganisms and impurities from reaching the wound bed, and was prepared at 14% w/v in chloroform/dimethylformamide (CHF/DMF) at 90/10% v/v (4 h at 50ºC); (middle) sodium alginate (SA) hydrogel loaded with the antimicrobial agents, polyethylenimine (PEI) and ceftazidime (CEF), examined against Staphylococcus aureus and Pseudomonas aeruginosa using the broth micro-dilution assay (determination of minimum inhibitory concentration or MIC), and used to maintain a moisture environment and absorb exudates. The hydrogel was obtained by solvent casting-phase inversion method using a 2%w/v SA solution and coagulation bath of 2%w/v CaCl₂. Finally, (inner) a second fibrous mat composed of PCL and polyethylene glycol (PEG), also examined against S.aureus e P.aeruginos (MIC of 256 µg/mL), was used to facilitate cell integration and recognition and reduce mat hydrophobicity. Mats were produced via electrospinning (12kV, 0.7mL/h, 17cm, 18G). The sandwich-like system was generated by pouring the hydrogel solution onto a casting mold lined with the inner layer and depositing the outer layer at the top of the viscous solution. After 1h of intimate contact, the casting solution was added and afterwards the scaffolding system was ready and totally detached from the mold. Data reports the effectiveness of this sandwich-like system for potential applications in CW care.