DNA Hybridization on Surfaces

The controlled arrangement of DNA molecules on surfaces represents one challenging contribution of nanotechnology to biology and medicine. In particular, one of the open issues in the field of DNA-based sensors is detecting the hybridization process with high precision in a real-life biological environment. Towards this end, we have studied the hybridization of single stranded (ss)-DNA anchored on a gold surface using the increase in height of the molecules upon hybridization with a label free target which is due to the much larger rigidity of ds- vs. ss-DNA. Nano-scale ss-DNA patches are assembled within oligo-ethylene-glycol terminated alkylthiol self-assembled monolayer on a gold substrate using nanografting (an atomic force microscopy-based nanolithography technique). Differential height measurements indicate that ss-DNA nano-patches do not show significant increase in height upon hybridization with complementary strands in high density regime. Moreover, the advantage of this system for biosensors and genomics applications will be discussed briefly in the end.