Hierarchical TiO₂–Ag/hydrogel coating used for outstanding antifouling detection of serotonin

Serotonin (5-HT) is an important neurotransmitter in vivo, regulating almost all human behavior and cognitive processes. Antifouling surface that can prevent undesirable adhesion is a key factor in the detection of 5-HT, hydrogels are considered as excellent candidates for non-fouling materials. It still remains a challenge to fabricate antifouling composites on electrode that can combine the properties of the hydrogels and surface morphology characteristics, at the same time, keeping good conductivity of the electrode. Herein, we report a new antifouling electrochemical biosensor for 5-HT detection. Using the photocatalytic activity of TiO₂ and the conductivity of Ag nanoparticles, the antifouling layer of P(VPA-SBMA-GMA) hydrogel was formed by in situ polymerization on the surface of hierarchical nanoscale TiO₂–Ag nanocomposite, 5-HT aptamers were further bound on the surface of the hydrogel for specific recognition. With these advantages, the constructed sensor had a wide detection range (0.5 pM–100 nM) and a lower detection limit (5 fM) for 5-HT.

Manufacturing process, material characterization and effect DPV diagram of a new electrochemical aptamer sensor.