Development of a Surface Plasmon Resonance-Based DNA Sensor and Its Application for Screening DNA-Targeted Anticancer Drugs

In this paper, we present a surface plasmon resonance (SPR)-based sensor for measuring DNA hybridization and DNA/small-molecule interactions. A mixed self-assembled monolayer (SAM) was used to optimize the biosensor sensitivity. It was observed that the mixed SAM formed by mixing 10 mM of 16-mercapto-1-hexadecanoic acid (16-MHA) and 6-mercapto-1-hexanol (6-MCH) at a 1:10 molar ratio showed the best results. Subsequently, avidin was attached to the carboxyl groups on the SAM to serve as a binding element for biotinylated single-stranded (ss)DNA. The ssDNA-coated sensor was first evaluated as a nucleic acid biosensor through a DNA-DNA hybridization assay for synthetic 28-mer ssDNA. A linear calibration curve was observed in the range of 0.25–2.5 µg/mL. Non-complementary DNA induced no significant SPR angle shift, which demonstrated the specificity of the assay. Secondly, the sensor was used to monitor the binding kinetics of DNA/small-molecule interactions in real time. The dissociation constant between imm...