Highly sensitive electrochemiluminescence biosensor based on novel TiO2-porphyrin organic framework with self-enhanced luminescent property

The electrochemiluminescence (ECL) signal strength in the ternary ECL system depends on the efficiency of the coreactants, and the coreaction accelerator has been demonstrated to be an effective catalyst. A self-enhanced ECL strategy was used in which the coreaction accelerator was generated in situ during the synthesis of luminophores in our work. A composite material (Zn-TCPP-TiO2-Ti3C2) integrating a luminophore (Zn-TCPP) and a coreaction accelerator (TiO2 NPs) was synthesized by a solvothermal method. The probe designed with tripropylamine-modified AuNPs ([email protected]) was immobilized on Zn-TCPP-TiO2-Ti3C2 by the sandwich structure. The immobilization not only increased the concentration of the coreactant at the electrode interface but also greatly shortened the electron transport distance with the luminophore and coreaction accelerator, thus further improving the ECL signal. Compared with the [email protected]/Zn-TCPP system, the ECL signal of [email protected]/Zn-TCPP-TiO2-Ti3C2 was amplified 3.5 times. Under the optimal conditions, the designed ECL biosensor exhibited a wide dynamic range from 1.0 × 102 to 1.0 × 105 particles μL−1 and a low detection limit of 11 particles μL−1 for exosomes. Importantly, this work not only developed a simple and ultrasensitive exosome detection system but also provided a novel possibility for the practical application of porphyrin-based metal-organic frameworks (Por-MOFs) in biological analysis.