Surface-Confined Building of Au@Pt-Centered and Multi-G-Quadruplex/Hemin Wire-Surrounded Electroactive Super-nanostructures for Ultrasensitive Monitoring of Morphine

Overuse and abuse of morphine (MOP), one of the main components of pericarpium papaveris, have attracted increasing attention in the medical field owing to its pharmacological and toxicological activity. Herein, we proposed a new electrochemical nano-biosensor for MOP detection based on surface-confined building of Au@Pt-centered and multi-G-quadruplex/hemin wire-surrounded electroactive super-nanostructures. The center Au@Pt was flower-shaped and irregularly protruded, allowing substantial loading of multiple G-quadruplex wire/hemin complexes on its surface to accomplish the assembly of electroactive supernanostructures. Interestingly, as the super-nanostructures were closely confined on the electrode surface, a significantly amplified electrochemical signal was thus obtained in the absence of MOP. In contrast, the introduction of target MOP can induce an intense competitive effect and strongly destroy the assembly process, resulting in the reduction of the electrochemical response that is correlated with the logarithmic concentration of MOP. Under optimal conditions, the electrochemical nano-biosensor is capable of highly sensitive detection of MOP in a dynamic concentration range from 1 ppt to 500 ppb. The limit of detection is achieved as low as 0.69 ppt, and the practical application was confirmed by examining MOP from chafing dish condiments. We expect the electrochemical platform utilizing this unique nanoarchitecture to provide rational guidelines to design high-performance analytical tools.