Patterned and switchable surfaces for biomaterial applications

Andrew Hook – Patterned and switchable surfaces for biomaterial applicationsof secreted collagen fibrils. Moreover, the inclusion of FN and CN in the cell culturemedia may also promote cell attachment on the PAAc.5.5. ConclusionThe characterisation of a polymer array containing non-uniform surface featuresusing SPRi has been achieved, overcoming the requirement for homogeneoussurfaces for comparative SPRi measurements. A method has been developedwhereby changes in reflectivity measured during a typical fixed angle SPRexperiment can be related to the corresponding shift in resonance angle. This processwas shown to theoretically produce equivalent responses for microarray polymerspots of 0-30 nm thickness when exposed to an equivalent change in refractive indexand was found to produce quantitatively comparable results in practice. Thisapproach has been utilised to study the adsorption of CN type I, FN and BSA to apolymer array of PAA, PEI and PLL. For this, a novel approach to producing a lowfouling background for SPR applications was developed by initially coating a SPRchip with a thin plasma polymer layer that was modified with HDI in order to attacha low-fouling PEG layer. BSA adsorption to the polymer array followed the expectedtrends assuming electrostatic interactions, however, CN type I and FN, despitehaving a negative charge, adsorbed on both positively and negatively charged surfacechemistries. The end on adsorption of both these polymers to PAA was suggested.This result highlighted the complex behaviour of biomolecules at surfaces and, thus,the difficulty associated with correlating protein and cellular behaviour.Comparison of protein adsorption studies with cell attachment assays conductedwith SK-N-SH in serum over 24 hr suggest that cell attachment is largely driven byelectrostatic interactions.5-205