3D Electrospun poly L-lactic acid nanofibrous structures coated with regenerated silk fibroin and silver nitrate for burn wounds

Abstract

Pediatric burn victims, who are the majority in Uganda, are treated with cotton gauze embedded with topical creams that require painful, frequent changes because of their adherence tendency due to absorption properties. This research developed a 3D-ES poly L-lactic acid (PLLA) nanofibrous structure coated with antibacterial properties that is also biocompatible and biodegradable. An optimized pristine 3D-ES structure had a height of 23.58 mm and a fiber diameter of 0.77 ± 0.05 µm (p > 0.05), suggesting uniform fiber diameters. It had a contact angle of 120°, 40.3% in vitro degradation, and 480.29% fluid take-up on Day 4. No cytotoxicity was observed by Lactate dehydrogenase (LDH) release assay, and cells adhered and grew, indicating biocompatibility. The 3D-ES structure was coated with regenerated silk fibroin (RSF), whose optimized extraction process was based on Activity-Based Costing (ABC) accounting for the total cost of producing 1 g of RSF, which cost $ 100.06 compared to the $379.58 cost of 1 g of Lyophilized RSF. With optimized spray parameters, silver nitrate (AgNO3) was coated onto the 3D-ES structure. Prior, the minimum inhibitory concentration (MIC) and maximum bactericidal concentration (MBC) of 0.5 mg mL-1 AgNO3 were analyzed and recorded as the 1st and Neat for all standard and clinical isolates for S. aureus and E. coli. The zone of inhibition (ZOI) decreased with increasing serial dilution, with the widest clearance being 24 mm for SE. coli clinical isolate. Overall, the 3D-ES PLLA structure coated with RSF and AgNO3 was biodegradable, biocompatible, and had antibacterial properties. This research introduces the potential of using 3D-ES drug-loaded structures as potential wound dressings.