Bifunctional TiO₂ Nanoflower-Induced H₄TCBPE Aggregation Enhanced Electrochemiluminescence for an Ultrasensitive Assay of Organophosphorus

Abstract

In this work, the aggregation-induced emission ligand 1,1,2,2-tetra­(4-carboxylbiphenyl)­ethylene (H4TCBPE) was rigidified in the Ti–O network to form novel electrochemiluminescence (ECL) emitter H4TCBPE-TiO2 nanospheres, which acted as an effective ECL emitter to construct an “on–off” ECL biosensor for ultrasensitive detection of malathion (Mal). H4TCBPE-TiO2 exhibited excellent ECL responses due to the Ti–O network that can restrict the intramolecular free motions within H4TCBPE and then reduce the nonradiative relaxation. Moreover, TiO2 can act as an ECL co-reaction accelerator to promote the generation of sulfate radical anion (SO4 •–), which interacts with H4TCBPE in the Ti–O network to produce enhanced ECL response. In the presence of Mal, numerous ligated probes (probe 1 to probe 2, P1–P2) were formed and released by copper-free click nucleic acid ligation reaction, which then hybridized with hairpin probe 1 (H1)-modified H4TCBPE-TiO2-based electrode surface. The P1–P2 probes can initiate the target-assisted terminal deoxynucleoside transferase (TdTase) extended reaction to produce long tails of deoxyadenine with abundant biotin, which can load numerous streptavidin-functionalized ferrocenedicarboxylic acid polymer (SA-PFc), causing quenching of the ECL signal. Thus, the ultrasensitive ECL biosensor based on H4TCBPE-TiO2 ECL emitter and click chemistry-actuated TdTase amplification strategy presents a desirable range from 0.001 to 100 ng/mL and a detection limit low to 9.9 fg/mL. Overall, this work has paved an avenue for the development of novel ECL emitters, which has opened up new prospects for ECL biosensing.

Solvent Regulation Induced Cathode Aggregation-Induced Electrochemiluminescence of Tetraphenylethylene Nanoaggregates for Ultrasensitive Zearalenone Analysis

“…Then, 10 μL of 3 mg/mL TPE NAs, 10 μL of 0.2% chitosan (CS), and 10 μL of Au nanoparticles (Au NPs, 16 nm) were dropped on the surface of GCE successively and baked in an oven (37 °C) to form a film on the electrode surface. Subsequently, the modified GCE was incubated with 10 μL of capture DNA (CP, 1 μM) for 6 h at 25 °C . After that, 10 μL of hexanethiol (HT, 1 mM) was dropped to block nonspecific sites.…”

High-Efficient Electrochemiluminescence of DNA-Au Ag Nanoclusters with Au NPs@Ti3C2 as a Novel Coreaction Accelerator for Ultrasensitive Biosensing

“…Recently, the introduction of coreaction accelerators has been a superior approach to expedite the redox of the coreactant for improving the ECL response of metal NCs, such as metallic oxide, 18 metal−organic framework, 19 and noble metal nanoparticles. 20 However, the above-mentioned coreaction accelerators exhibited an inadequate catalytic activity to electrogenerated reactive radicals.…”