Tuning the optical, electrical, anti-microbial, and swelling activity of nanowires manganese dioxide-loaded chitosan...

Skin wound healing is undoubtedly a complex and challenging process. Creating innovative bio-nanocomposites for skin care and wound healing/dressing applications are currently an urgent need. In this context, a mixture of chitosan (CS) and MnO₂ nanowires (NWs), as potential wound dressing nano-film, are systematically investigated for optical, electrical, and antibacterial applications. The crystallinity of the materials was investigated through XRD, while FTIR was used to examine the interactions between the CS films and the MnO₂ nanofiller. The resulting nanocomposite membranes exhibit superior swelling capacity than that of the pure CS membrane. Additionally, the thermal stability of the films was evaluated, demonstrating the highest stability of composite samples. The optical properties, including bandgap energies and refractive indices, can be adjusted by tuning the content of MnO₂. Remarkably, the refractive index dropped from 3.76 in pure CS film to 3.4 in the highest fraction of MnO₂ (CS-4 wt% MnO₂). The impedance analysis was further improved for the (CS-4 wt% MnO₂) sample, posing lower interfacial resistance. A comprehensive investigation of the antibacterial performance of the prepared films was carried out against five bacteria types. The pure CS film exhibited mostly inhibitory effects against Gram-positive bacteria (i.e., B. subtilis, and S. aureus) between the 19 and 14 mm range, while the Gram-negative bacteria (i.e., E. coli, and P. aeruginosa) showed activity between the 19 and 20 mm range, with an effect on A. niger and C. albicans 17 and 22 mm. However, the addition of MnO₂ has significantly increased its antimicrobial activity. Overall, the prepared CS films demonstrate great potential for multifunctional applications, including antibacterial, wound healing, and optoelectronics.