Electrochemiluminescence biosensor for thrombin detection based on metal organic framework with electrochemiluminescence indicator embedded in the framework

Ru(dcbpy)32+-polyethyleneimine-L-lysine (Ru-PEI-L-lys) had been immobilized on metal organic frameworks (ZIF-8) to form an electrochemiluminescent(ECL) indicator (Ru-PEI-L-lys-ZIF-8). In this ECL indicator, PEI-L-lys is used as a co-reactant. Platinum nanoparticles (PtNPs) has been mixed with Ru-PEI-L-lys-ZIF-8 to form a thin film to increase the electron transfer rate and enhanced the ECL response of the system. The prepared material had been characterized carefully and been combined with high selectivity of aptamer to develop a ECL biosensor for thrombin detection. RecJf exonuclease (an ssDNA specific exonuclease) assistant target recycling amplification has been adopted to enhance the sensitivity of the system. The ECL response of the system has a linear relationship with logarithm of thrombin concentration in the range of 1 fM to 10 pM with a detection limit of 0.02 aM. This work not only provides a new strategy for the design and synthesis of high performance and stable ECL indicator, but also opens up a new approach for the development of highly sensitive ECL sensors for biological analysis.