In situ assembly of well-dispersed Ag nanoparticles on the surface of polylactic acid-Au@polydopamine nanofibers for antimicrobial applications

Nanofibrous membranes which exhibit bacteriostatic functions are a good strategy to prevent microorganisms from adhering to the surface of biomaterials. Here, we report the synthesis of such a nanofibrous membrane which can be applied to biological coatings to reduce bacteriostatic functionality. Ascorbic acid was utilized to reduced chloroauric acid to gold nanoparticles (AuNPs). Dopamine was then polymerized upon AuNP surfaces by ultrasound-assistance, to synthesize core-shell structured polydopamine-coated AuNPs (Au@PDA NPs). The Au@PDA NPs were then mixed with polylactic acid (PLA) for electrospinning into cylindrical nanofibers (136.6 nm diameter). PLA-Au@PDA nanofibrous membranes were finally immersed in silver nitrate for in situ reduction into a silver nanoparticle (AgNP) coating to yield PLA-Au@PDA@Ag nanofibers. The PLA-Au@PDA@Ag nanofibers were characterized based on field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and contact angle analyses. The antibacterial properties of the PLA-Au@PDA@Ag nanofibers were examined based on the optical density absorbance of bacterial cell suspensions, traditional colony plate counts, zone inhibition analyses, and field-emission scanning electron microscopy. Escherichia coli and Staphylococcus aureaus respectively served as Gram negative and positive bacterial models of industrial relevance. The data conclusively illustrates the antimicrobial and biomedical applications of PLA-Au@PDA@Ag nanofibers.