Bilayer nonwovens using natural rubber, poly(lactic acid) and bactericidal nanoparticles for wound dressings

Wound healing poses a significant challenge in healthcare, impacting not only on patients' quality of life but also placing a substantial financial burden on healthcare systems. Bilayer nonwovens have emerged as a promising solution for wound dressings due to their porous morphology, providing a high surface area for cellular adhesion and growth, and their permeability, allowing proper oxygen and fluid exchange to promote wound healing. When bactericide materials are added to the formulation, they can decrease or prevent infection caused by microorganisms, further aiding the healing process. Solution blow spinning is an appealing technique for creating bilayer nonwovens as it can produce high yields at a low cost. Yet, even though natural rubber boasts a well-established safety record in biomaterials, it remains an underexplored candidate for generating micronanofibrous structures. In this study, solution blow spinning was employed to fabricate bilayer composite nonwovens for wound dressing materials. The material architecture consisted of a bottom layer composed of a blend of natural rubber, poly(lactic acid) (PLA), and polyethylene glycol in the respective proportion of 2:1:3 w/ w and a top layer composed of PLA and ZnO nanoparticles added in concentrations of 1%, 2.5%, and 5% based on the PLA mass of this layer. The top layer was further functionalized with Ag nanoparticles through spraying. The obtained materials demonstrated satisfactory hydrophobicity for cellular adhesion in the bottom layer, ranging from 51.95 degrees to 92.20 degrees of water sessile drop contact angle, and tunable mechanical strength, which could be controlled by varying the content of ZnO nanoparticles. Additionally, the material showed antimicrobial properties due to the presence of added Ag nanoparticles, able to inhibit E. coli, S. enterica serovar Typhimurium, and S. aureus by direct contact. Besides, the nonwoven prevented the passage of microorganisms due to the pore size of the structure. Overall, the unique properties of the developed material, such as its low cost, ease of production, and remarkable wound-healing properties, make it a promising candidate for wound dressing applications.