Surface Behaviour and Molecular Recognition in DNA Microarrays from N,N-Dimethylacrylamide Terpolymers with Activated Esters as Linking Groups

A series of terpolymers made of DMA, NAS and MAPS were synthesized by free radical copolymerization and used as functional coatings for the fabrication of glass slide DNA microarrays. The surface properties of coated glass slides were investigated through contact angle measurements, ellipsometry and atomic force microscopy. The terpolymer molecular weight showed a moderate effect on surface tension (γs = 56-62 mN · m-1), but no clear effect on polymeric layer thickness (5-8 nm) and roughness. Hybridization experiments with amine-functionalized oligonucleotides gave the best fluorescence intensity results for microarrays coated with intermediate- molecular-weight terpolymers. Finally, an accelerated ageing test of the microarray in a humidity chamber showed a nice relationship between decay curves of contact angle against water and fluorescence intensity.