Figure 10.

SPR assay for ATP detection amplified by DNA-based hybridization chain reaction (HCR). (A) The S1-magnetic bead conjugates were prepared by direct immobilization of an amine-modified ATP aptamer linked to an activated carboxylate group on magnetic beads through the EDC/NHS chemistry, and then hybridized with its complementary oligonucleotide S2; (B) The strategy of continuous SPR monitoring of trigger DNA on a DNA chip array. Following a magnetic separation from the solution, the gold surface, on which the thiolated capture DNA was immobilized through S-Au bond, was treated with the sample containing S2. The released S2 functioned as trigger DNA to bind to the cohesive end of H1 in the presence of ATP. Adapted from [123].