Plasma polymerised poly(methyl methacrylate) and cyclopropylamine films on polylactic acid nanofibres by electrospinning

Abstract

Polylactic acid (PLA) is a thermoplastic, biodegradable polyester. It can be derived from natural resources such as corn starch, cassava starch or sugarcane. PLA can also be classified as a bioplastic. To produce PLA in the industrial scale, the most common ways are to polymerise two monomers: lactic acid and cyclic di-ester (lactide) with various metal catalysts in solution or suspension. PLA can be manufactured by injection moulding, extrusion, casting, and in most recent techniques such as electrospinning and three dimensional printing. The variety of different processes makes PLA available to a wide range of applications. PLA is soluble in tetrahydrofuran, dioxane, chlorinated solvents and heated benzene. The selected solubility provides limited choices for dissolving PLA into solution for electrospinning process to fabricate nanofibres. One advantage of using electrospinning is to create materials with very high porosities with complex geometry, maintaining its biodegradability, enhancing bio-adhesion and extracellular chemical signal transduction for cell culture. In this study, we fabricate PLA nanofibres by electrospinning and then coat these fibres with poly(methyl methacrylate) (PMMA) and cyclopropylamine (CPA) using plasma polymerisation. PMMA is a transparent, nontoxic thermoplastic polymer with highly stable physical and chemical properties whilst CPA is a volatile and chemically active molecule with a primary amine. In addition to fabrication, we also investigated the structure and morphology of the PLA fibres with/without PMMA/CPA coatings by SEM, EDS, FTIR and AFM. These fibres are tested for their biocompatibility via cell culture of 3T3 fibroblasts (mouse embryonic). The 3T3 cell line is the standard fibroblast commonly used for DNA transfection studies. The culture is assessed by MTT assays and cell proliferation to evaluated cellular activities on the PLA nanofibres.