Integration of phosphate functionalized Pt/TiO2 and Ru(bpy)32± sensitization for ultrasensitive assay of adenosine deaminase activity on a novel split-typed PEC aptasensor

To date, it is still a challenge for high-performance photoelectrochemical (PEC) assay of low-abundance aden-osine deaminase (ADA) in fundamental research and clinical diagnosis. Herein, phosphate-functionalized Pt/ TiO2 (termed PO43-/Pt/TiO2) was prepared as ideal photoactive material to develop a split-typed PEC aptasensor for detection of ADA activity, coupled by a Ru(bpy)32 +/- sensitization strategy. We critically studied the effects of the PO43-and Ru(bpy)32 +/- on the detection signals, and discussed the signal-amplified mechanism. Specifically, hairpin-structured adenosine (AD) aptamer was splited into single chain via ADA-induced catalytic reaction, and subsequently hybridized with complementary DNA (cDNA, initially coating on magnetic beads). The in-situ formed double-stranded DNA (dsDNA) was further intercalated by more Ru(bpy)32 +/- to amplify the photocur-rents. The resultant PEC biosensor showed a broader linear range of 0.05-100 U L-1 and a lower limit of detection (0.019 U L-1), which can fill the blank for analysis of ADA activity. This research would provide some valuable insights for building advanced PEC aptasensors in ADA-related research and clinical diagnosis.

Automated summary

A split-typed PEC aptasensor using phosphate-functionalized Pt/TiO2 material was developed for the detection of low-abundance aden-osine deaminase (ADA) activity. The biosensor showed a broad linear range and a low limit of detection, filling a gap in the analysis of ADA activity. This research provides valuable insights for ADA-related research and clinical diagnosis.