Development of Poly(lactic acid)/Poly(ethylene glycol) Nanofibers for Wound Healing Patch with Anti-bacterial and Anti-inflammatory Properties

Abstract

This work proposes the fabrication of blended poly(lactic acid) (PLA) electrospun nanofibers which were separated into 3 parts. The first part is investigation of blending PLA nanofibers (NFs) with low molecular weight poly(ethylene glycol) (LPEG)(Mw=4000) and chitosan (CS) loaded with Centella Asiatica extracts (CAE) using the mixture solvents formic acid/chloroform/acetone and adding ethanol, PLA/PEG/CS/CAE can be electrospun into smooth nanofibers but there is still a problem with immiscibility of PLA, PEG, and CS. Although the addition of CS and PEG improves mechanical properties, all samples show hydrophobicity evidenced by water-contact angle (WCA) and Fourier Transform Infrared (FTIR) results. Therefore, we need to develop a new solvent system and change the type of anti-bacterial by using ZnO nanoparticles (NPs) instead of CS to the blended polymer and try to study the effect of LPEG and HPEG for optimum wettability. The second part is development of the blended PLA electrospun nanofibers with LPEG and High Mw PEG (Mw=900,000) (HPEG) by various ratios of PLA and LPEG or HPEG as 90:10, 70:30, and 50:50 respectively dissolved in chloroform and acetonitrile by the ratio of 60:40 that are successfully fabricated via electrospinning. The result of adding LPEG made the fibers smaller, but HPEG is large because of the difference of molecular weight which also affects the viscosity. The hydrophilicity appears in the ratios of 70:30 HPEG and increased swelling and moderated rate of degradation. Therefore, we selected 70:30 to develop in the 3rd part by adding ZnO NPs and CAE to improve anti-bacterial and cytotoxicity. The final part is the fabrication of 70PLA/30HPEG electrospun fiber loaded 2% ZnO and 0.7-2.8% CAE. When ZnO NPs and CAE were added, there was a decrease in fiber degradation. CAE release patterns related to degradation with 0.7 and 2.8 having similar diffusion from the fibers and 1.4 having a faster transport. Possibly, CAE may be more containing in the pore matrix and polymer matrix. 2%ZnO NPs inhibited bacteria. PLA NFs is non-toxic but adding HPEG is toxic. However, the effects of adding HPEG and doped ZnO NPs and CAE need further studies about the mechanism of cytotoxicity.

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