Specific unlocking of the butterfly effect: nanointerface-based electrochemical biosensing of adenosine triphosphate and alkaline phosphatase

The purpose of this study was to achieve a specific unlocking of the butterfly effect: nanointerface-based electrochemical biosensing of adenosine triphosphate (ATP) and alkaline phosphatase (ALP). Based on the Faraday-cage concept reported first by our group, we built a new outer Helmholtz plane (OHP)-based electrochemical biosensor by using an unique nanocomposite involving three-dimensional graphene-Au nanoparticles (3D-GO-AuNPs), tetrahedral DNA nanostructures (TDNs), and separated ATP aptamers, in which methylene blue (MB) was employed as the electrochemical signal output. In this process, the prepared nanocomposites were attached favorably onto the TDN substrate electrode surface due to the interaction of ATP and its aptamer, creating a better OHP of the electrode owing to its large enough specific surface area; then a detection limit of 0.25 pM was calculated by 3 δ /slope. Whereas, the hydrolysis for ATP of ALP can hinder this binding process, therefore, the biosensor could be indirectly applied for ALP analysis with a detection limit of 0.21 mU/L (3 δ /slope). Since some small changes of the two targets will set off a whole series of changes in system, the OHP-extended biosensor provides a superior electrochemical platform for complex biological processes with causal relationships in clinical diagnosis and drug development, similar to the butterfly effect. Graphical abstract