Electrospun titania fiber mats spin coated with thin polymer films as nanofibrous scaffolds for enhanced cell...

The incorporation of inorganic materials into electrospun nanofibres has recently gained considerable attention for the development of extracellular matrix-like scaffolds with improved mechanical properties and enhanced biological functions for tissue engineering applications. In this study, polymer-inorganic composite fibres consisting of poly(2-ethyl-2-oxazoline) (PEOXA) and tetrabutyl titanate as the titanium precursor were successfully fabricated through a combined sol-gel/electrospinning approach. PEOXA/Ti(OR)_n composite fibres were obtained with varying amounts of polymer and titanium precursors. Calcinations of the composite fibres were performed at varying temperatures to produce TiO₂ fibres (TiO₂ -T-60) with anatase, anatase/rutile mixed phase, and rutile crystal structures. Thin polymer films (i.e., poly(2-ethyl-2-oxazoline) (PEOXA), polycaprolactone (PCL), and poly(methyl methacrylate) (PMMA)) were subsequently deposited onto TiO₂ -T-60 fibre mats by spin coating to facilitate handling of the electrospun substrates after calcination, which are rather brittle and disintegrate easily, and to probe cell-materials interactions. The cellular behaviour of mouse L929 fibroblasts after culture periods of 1-5 days was compared on the following fibre scaffolds: PEOXA/Ti(OR)_n , TiO₂ -T-60 (T = 600, 650, and 700 °C), TiO₂ -T-60 spin-coated with thin PCL film (PCL/TiO₂ -T-60), and pure PCL. The results obtained from in vitro cell culture studies for the lactate dehydrogenase release assay and confocal microscopic visualization pointed out the synergistic interplay between the TiO₂ crystal structure and spin-coated PCL film in facilitating cell interactions with the scaffold surface. The L929 cells were observed to adhere and proliferate better on the surface of TiO₂ -700-60 having the rutile structure than on the surfaces of TiO₂ -600-60 and TiO₂ -650-60 fibre scaffolds with anatase and anatase/rutile mixed phase structures, respectively.