Highly sensitive surface-enhanced Raman scattering detection of adenosine triphosphate based on core-satellite...

As an important small molecule, adenosine triphosphate (ATP) plays an important role in the regulation of cell metabolism and supplies energy for various biochemical reactions in organisms. We herein developed a sensitive surface-enhanced Raman scattering (SERS) biosensor for highly specific detection of ATP using core-satellite assemblies. To construct the aptamer-based biosensor, a known ATP binding aptamer was divided into two segments. The first thiol-labeled segment (DNA1) of the aptamer was immobilized on silver-coated gold nanostar (AuNS@Ag) surfaces by an Au-S bond. The second thiol-labeled segment (DNA2) was linked via an Au-S bond to gold nanoparticles (AuNPs), which were also decorated with a Raman active reporter molecule, 4-mercaptobenzoic acid (4-MBA). In the presence of ATP, DNA2 associated with DNA1, leading to greatly enhanced 4-MBA Raman intensity. The enhance Raman signal was linearly related to the logarithm of the ATP concentration in the range from 1 pM to 1 nM, with a detection limit of ∼0.5 pM. In addition, the sensor featured an excellent selectivity to ATP over other interfering analogues of ATP (GTP, CTP, and UTP).