Preparation of a Branched DNA Self-Assembled Monolayer toward Sensitive DNA Biosensors

To realize an efficient hybridization of oligonucleotides, a DNA self-assembled monolayer (SAM) composed of branched probe DNA containing single- and double-stranded portions was prepared on a gold substrate. Hybridization using the SAM was monitored in situ by surface plasmon resonance (SPR). By controlling the surface coverage of the probe DNA, hybridization efficiency was optimized. SPR results strongly indicate that all probe sites are accessible for hybridization under optimized conditions regardless of the position.