Patterned and switchable surfaces for biomaterial applications

CHAPTER 3.COMPARISON OF THE BINDING MODE OFPLASMID DNA TO ALLYLAMINE PLASMA POLYMERAND POLY(ETHYLENE GLYCOL) SURFACES3The content of this chapter is based upon reference [188].3.3.1. IntroductionNucleic acid probes have been used extensively in recent years for applicationssuch as biomimetics, ‘smart’ drug delivery, biosensing and tissue engineering [3, 4,6] and for tasks such as DNA purification and gene therapy [1, 8, 14, 127]. Duringthese applications the nucleic acid probes are often bound or associated to the surfaceof a biomaterial, thus, in order to increase the scope and capabilities of these devicesadvanced control over DNA manipulation at surfaces is required. Insight into themode of DNA association with a particular surface of interest is, thus, pivotal inorder to maximise DNA-surface interactions and allow for advanced manipulation ofDNA at a surface such as switchable binding.Double-stranded DNA can generally be regarded as a coiled rod with apurine/pyrimidine core and a phosphate and pentose sugar exterior. The negativecharges of the phosphate groups endow DNA with the characteristic feature of ananionic polyelectrolyte. For this reason, the production of surfaces with a positivesurface charge, often achieved by the incorporation of amine functionality, has beeninvestigated and achieved by a number of strategies with the basic aim to increaseDNA surface adsorption via electrostatic interactions [27]. As well as commonlyutilised wet chemical silanisation strategies [9, 30] and coating formation withpolyamines [29, 78], aminated surfaces have been produced by plasma3-97