Formation Mechanism of a Novel Core-Shell with Tetradecyl Dimethyl Benzyl Ammonium Modified Montmorillonite Interlayer Nanofibrous Membrane and its Antimicrobial Properties

Abstract

A novel core-shell with a tetradecyl dimethyl benzyl ammonium chloride-modified montmorillonite (TDMBA/MMT) interlayer silk fibroin (SF)/poly(lactic acid) (PLLA) nanofibrous membrane was fabricated using a simple conventional electrospinning method. Scanning electron microscopy and pore size analyses revealed that this core-shell with TDMBA/MMT interlayer maintained its nanofibrous morphology and larger pore structure more successfully than SF/PLLA nanofibrous membranes after treatment with 75% ethanol vapor. Transmission electron microscopy and energy-dispersive X-ray spectroscopy analyses testified that the SF/PLLA-TDMBA/MMT nanofiber exhibited a core-shell with an interlayer structure, with SF/PLLA in the core-shell layer and TDMBA/MMT in the interlayer. The formation of a core-shell with interlayer nanofiber was primarily attributed to the uniform dispersion of TDMBA/MMT nanosheets in solution owing to its exfoliation using hexafluoroisopropanol (HFIP) and then developing a stable spinning solution similar to an emulsion. Compared to SF/PLLA nanofibrous membrane, core-shell with TDMBA/MMT interlayers of SF/PLLA nanofibrous membrane exhibit enhanced hydrophilicity, thermal stability, mechanical properties as well as improved and long-lasting antimicrobial performance against Escherichia coli and Staphylococcus aureus without cytotoxicity.

Keywords: core-shell with interlayer nanofiber, montmorillonite, eletrospinning, Silk fibroin, antimicrobial properties