Preparation And Antibacterial Property Of AgNPs/PLLA Nanofiber Membrane

Guided bone regeneration(GBR) technique physically separated gingival connective tissue and epithelium from areas of active bone formation with a barrier membrane to favor bone regeneration. Currently, GBR technique is one of the most common and promising augmentation techniques to regain sufficient width and height of the jawbone at oral implant sites, or to preserve alveolar sockets after tooth extraction. Also, it is an important part of surgical procedures to heal peri-implantitis defects. The bacterial infection is the major reason for failure of GBR technique in vivo, hence, GBR biomaterial with antibacterial property has an extreme significance for clinical applications. Poly-L-lactic acid(PLLA) electrospun nanofiber membrane has the similar structure with extracellular matrix, its special high specific surface area and pore texture beneficial for cell adhesion and proliferation, especially suitable for GBR application.In this study, we synthesized Ag NPs-loaded PLLA nanofibers by treating PLLA electrospun nanofibers with dopamine, which can self-polymerize and spontaneously form a thin, surface-adherent PDA coating and then in situ regenerate Ag NPs through second reaction. Six different periods(0 h, 1 h, 3 h, 6 h, 9 h, 24 h) for Ag NPs generation, corresponding to different Ag NPs dosages immobilized in biodegradable PLLA electrospun membranes, were controlled to determine the concentration of Ag NPs. Its physical-chemical properties and structure characters were determined by scanning electron microscope, X-Ray Diffraction, X-ray photoelectron spectroscopy, etc. Its antibacterial ability against Staphylococcus aureus was evaluated by the agar-diffusion and plate colony-counting methods, and its cytotoxicity was detected by CCK8 method. The results showed that PDA and Ag NPs shifted the surface of PLLA nanofibers from hydrophobic to hydrophilic, and this facile strategy realized Ag NPs homogeniously dispersion on the surface of PLLA nanofibers. The amount of Ag NPs on PLLA nanofibers was growing with reaction time, leading to an initial increase, followed by a steady antibacterial ability. Worth mentioning, after 14 days, the inhibition zones are still rather obvious. However, PLLA electrospun membranes treated with more than 6 hours exhibited a worse cytocompatibility. Thus, on the basis of antibacterial results and toxicity evaluations, PLLA electrospun membrane treated with 3 hours was considered as the most suitable combination, which is safe and effective for clinical application.