Metal coating deposition on electrospun fibers for enhanced biological performance

Abstract

A Guided bone regeneration (GBR) membrane has been extensively used in the repair and regeneration of damaged periodontal tissues. Fibrous membranes, consisting of a poly(lactic acid) (PLA), is a good candidate for GBR membranes for its biological and mechanical properties. However, due to its poor osteoconductivity and cellular affinity of PLA itself, its application for GBR has been limited. To achieve the better biological performance and desirable properties in GBR, various methods have been developed and investigated including e-beam deposition, microarc oxidation, ion implant doping, and thermal oxidation etc. Among them, deposition of bio-metal coating layer is a promising way to enhance the biological performance of polymer substrate. In this study, we introduced DC sputtering deposition system as a platform for forming stable metal coating layer on electrospun PLA fiber surface. The metal coating layers created by DC sputtering deposition have been studied for the various type of biological property enhancement agent such as osteo-conductivity, cellular affinity, and antimicrobial effect as GBR. Firstly, the Ta is coated on electrospun PLA fiber surface through DC sputtering deposition to enhance biological performance. Various synthetic degradable biopolymers including PLA are being used as GBR materials due to their superior mechanical property to natural biopolymers however their inherent low cellular affinity limits their application. Hence, enhancement of biological property of synthetic polymer GBR is required. Therefore, Ta, which is very widely known as its excellent biological properties, is adapted as a coating material. Coating time (3 min to 5 min) and the target current (50, 75 mA) was varied to find optimum condition of the coating. And the coating stability was evaluated through SEM observation after tensile strain is given. The coating was very stable after the tensile strain was applied. In vitro cell test using MC3T3-E1 cells was performed to check biological effectiveness of Ta coating on the fiber surface. In terms of attachment and proliferation of cells, the biological activity of Ta coating layer was significant. This study demonstrated that the Ta coating layer created by DC sputtering deposition was stable and is effective for the enhancement of biological performance of PLA electrospun membrane as GBR. In the second study, Antimicorbal property was adapted using Ag as a coating material. For GBR restoration, many studies indicate that the proliferation of bacteria is one of the biggest obstacles because it disturbs the tissue regeneration and occur additional complications. Thus, we coat the Ag with mask to control the Ag coated area on Ta coated PLA fibrous membrane to expose both metals by conventional DC sputtering process. The antibacterial property of the specimens was evaluated with Escherichia coli and Staphylococcus Aureus. And the cytotoxicity of the different content of Ag was evaluated using MC3T3-E1 cells. The antibacterial activity was very effective and it increased with the area of Ag coating increased. Only Ag&Ta (20:80) sample did show the cytotoxicity in terms of cell viability. This study proved that the Ag ion from the coating layer created by DC sputtering deposition was very effective antibacterial agent.