Surface Plasmon Resonance (SPR) Determination of Adenosine Triphosphate (ATP) Using Silver (I) induced Configuration Changes of a Single Stranded DNA Probe with Cytosine (C)

ATP is related to the occurrence of many diseases, its facile, sensitive and accurate determination in real samples is needed for disease screening and treatment. Although some methods realized the sensitive detection of ATP using the signal amplification of cyclic reactions or nanoparticles, complex experimental processes limit their applications. In this paper, we report a simple surface plasmon resonance (SPR) method based on a single stranded DNA probe. The probe has dual recognition sites of ATP and Ag+; namely the ATP aptamer located in the middle of the probe and five cytosine (C) at both ends of the probe. In the absence of ATP, the probe transforms into a rigid hairpin structure by forming C-Ag+-C structures and produces a large SPR signal. However, once the probe interacts with ATP, three-dimensional structures are formed, and then the Ag+-induced probe configuration change is smaller, resulting in an small SPR signal. The signal difference before and after the probe interacts with ATP is proportional to the analyte concentration. The probe configuration change is in the optimum area for SPR detection, ensuring the sensitive ATP determination. The signal difference has a linear response with the logarithm of ATP concentration from 0.05 to 500 nM with a detection limit of 15 pM. Moreover, the strategy was demonstrated to determine ATP in serum samples with satisfactory recoveries. The results show that this simple and sensitive method has potential applications for clinical ATP determination.