The use of cell sheets for tissue engineering applications has considerable advantages over single cell seeding techniques. So far, only thermoresponsive surfaces have been used to manufacture cell sheets without chemically disrupting the cell-surface interactions. Here, we present a new and facile technique to prepare sheets of epithelial cells using plasma polymerised acrylic acid films. The cell sheets are harvested by gentle agitation of the media without the need of any additional external stimulus. We demonstrate that the plasma polymer deposition conditions affect the viability and metabolic activity of the cells in the sheet and relate these effects to the different surface properties of the plasma polymerised acrylic acid films. Based on surface analysis data, a first attempt is made to explain the mechanism behind the cell sheet formation. The advantage of the epithelial cell sheets generated here over single cell suspensions to seed a PLGA scaffold is presented. The scaffold itself, prepared using a mould fabricated via photolithography, exhibits a unique architecture that mimics closely the dimensions of the native tissue (mouse intestine).

This paper reports on the application of surface chemical gradients to study mammalian cell interactions with synthetic surfaces and investigates if the cell response on certain parts of the gradient is the same as that on uniform surfaces of equivalent chemistry. The gradients, formed using a diffusion-controlled plasma polymerisation technique, were fabricated such that cell response to a large range of different chemistries on a single sample could be investigated. Surface chemical gradients from hydrophobic plasma polymerised hexane (ppHex) to a more hydrophilic plasma polymerised allylamine (ppAAm), previously used to control cell density within 3D tissue-engineering scaffolds, were formed on glass coverslips. Surface characterisation was carried out to determine water contact angles (WCA), elemental composition, coating thickness and topography of the chemical gradients. Cell response was assessed following culture of 3T3 fibroblasts on both steep and shallow gradients. Fibroblasts adhered and proliferated preferentially on ppAAm (WCA∼60°) showing a gradual decreasing cell density towards the hydrophobic ppHex (WCA∼93°). Experiments on a uniform ppAAm surface revealed that there was a significant difference in cell density when compared to the gradient samples. The initial number of cells that adhered to the surface was confirmed as the difference between the uniform and graduated ppAAm samples, and it is assumed that this difference relates to different cell–cell signalling processes and/or greater protein production from surrounding cells on these two samples formats.