Patterned and switchable surfaces for biomaterial applications

CHAPTER 2.SPATIALLY CONTROLLED ELECTRO-STIMULATED DNA ADSORPTION AND DESORPTION FORBIODEVICE APPLICATIONS2The content of this chapter is based upon references [34, 174, 175].2.2.1. IntroductionThe development of biodevices, which includes systems for ‘smart’ drug delivery,tissue engineering, biosensing, biomimetics, implant biocompatibility and microarraytechnology [3-8] promises to provide solutions to a vast array of biomedicalproblems by enabling the manipulation and study of biomolecules and living cells ina controlled, high-throughput and/or application specific fashion. The developmentof DNA and protein microarray technology has been particularly successful inrevolutionising the way scientists have been able to study gene expression byproviding a high-throughput method of analysis where entire genomes can be studiedon a single array [101, 176]. In recent years, the scope of microarray technologieshas been broadened by the development of a transfected cell microarray (TCM) [8]consisting of complementary DNA (cDNAs) arrays spotted onto a glass slide ataddressable locations. Human embryonic kidney (HEK) cells seeded onto this DNAarray were observed to take up DNA creating regions of localised transfection withina lawn of non-transfected cells [8]. Despite the successful application of TCMs anumber of inherent limitations remain unsolved. A successful mechanism for theprevention of cross-contamination of cells and DNA between adjacent colonies orDNA spots has not been achieved, which limits the effective density of these arrays.TCMs also suffer from low transfection efficiencies limiting their use to cell lines2-63