Covalent Immobilisation of PVA‐MA Hydrogels on Plasma‐Activated Coatings: Achieving Superior Adhesion by Reagent‐Free Formation of a Nanoscale Primer Layer

Hydrogel coatings provide a promising pathway to tailor and improve cell culture surfaces, maintaining bulk material properties desired for handling and optical measurement while providing cell–surface interactions vital for optimising cell behaviour. For immobilised hydrogels to be useful, layers of this structure must be robustly adhered to the substrate and able to withstand strain from sources such as tensile forces exerted by adherent cell lines and fluid streams in microfluidic devices. Plasma‐activated coatings (PAC) are investigated here as a method for robust and translatable hydrogel immobilisation. Results show that embedded radicals within the PAC can immobilise methacrylated poly‐vinyl alcohol hydrogels, forming nanometer‐thick (reagent‐free) to millimeter‐thick (photoinitiator‐assisted) hydrogel layers. Utilisation of the nanometer reagent‐free layer as a ‘primer layer’ before forming photoinitiator‐assisted millimeter‐thick layers is a novel approach that results in superior adhesion of the thicker gel layers. When used as a cell culture surface for MCF‐7 cells, E cadherin and vinculin signalling significantly ( p < 0.05) increased (for physiologically relevant High MA hydrogel compared to the glass control). This work therefore outlines the novel reagent‐free primer layer approach as a method for creating hydrogels with superior adhesion for in vitro culture of cells.