n pH 7.8 Tris-HCl buffer solution, the aptamer (Apt 1) combined with its complementary aptamer (Apt 2) to form double-strand DNA (dsDNA) that can not protect nanosilver (AgNP). Under the action of NaCl, the AgNP particles were aggregated to large particles that exhibited a resonance scattering peak at 500 nm. Upon addition of adenosine triphosphate (ATP), it reacted with the Apt 1 of dsDNA to produce stable ATP-Apt 1 conjugate, and the released Apt 2 combined with AgNP to form stable AgNP-Apt 2 conjugate. When ATP concentration increased from 16.5 to 1650 nmol/L, the stable AgNP-Apt 2 increased, and the aggregated AgNP decreased. Thus, the RS intensity at 500 nm decreased linearly. Results showed that the AgNP-Apt 2 exhibited strong catalytic effect on the Cu₂O particle reaction between glucose and Cu(II), and the product of Cu₂O particles appeared a RS peak at 610 nm. When ATP concentration increased, the AgNP-Apt 2 increased, the RS intensity at 610 nm enhanced linearly. The enhanced RS intensity was linear to ATP concentration in the range of 4.95～165 nmol/L, with a detection limit of 1.8 nmol/L ATP. Thus, a highly sensitive, selective and simple RS assay was proposed for ATP.

Key words: ATP, aptamer, nanosilver catalysis, resonance scattering spectral assay