Jun-Tao Cao,Fu-Rao Liu,Fang Hou,Juan Peng,Shu-Wei Ren,Yan-Ming Liu
The cathodic electrochemiluminescence (ECL) behaviour of nontoxic MoS2 quantum dots (QDs) was studied for the first time using potassium peroxydisulfate as the co-reactant. Ag-PAMAM NCs, serving as difunctional tags for quenching and enhancing ECL of MoS2-reduced graphene oxide composites, were introduced into the ECL detection system for signal amplification. By modulating the interparticle distance between MoS2 QDs and Ag-PAMAM NCs, the ECL quenching from resonance energy transfer and the ECL enhancement from surface plasma resonance were realized. Coupling the good ECL performance of MoS2 QDs with the excellent ECL quenching and enhancement effects of Ag-PAMAM NCs, a novel MoS2 QDs-based ECL biosensing platform for sensitive detection of microRNA-21 was achieved with a detection limit of 0.20 fmol L−1 (S/N = 3). This method was successfully applied to the determination of microRNA-21 in human serum samples with recoveries of 90.0–110.0%, suggesting great potential for its applications in biological and chemical analysis.
Pre-oxidation is a simple and effective strategy to enhance the electrochemiluminescence (ECL) of Au nanoclusters. But the pre-oxidation ECL enhancement mechanism is still not clear. Herein, an in-situ formation immobilized coreactant promoters mechanism was proposed and verified by using Eu-doping methionine-stabilized Au nanoclusters (Met-AuEuNCs) as the model, with the ECL intensity 3.72-fold of that of Met-AuNCs. The ECL of Met-AuEuNCs was further enhanced 24.3-fold via pre-oxidation in 100 mM triethanolamine (TEOA) at the potential step of 1.0 V for 60 s, obtained a high ECL quantum yield of 143 %. The pre-oxidized Met-AuEuNCs reserved 20.1-fold ECL enhancement ratio after storing for 12 h and generated intense self-ECL in the absence of coreactant. Immobilized coreactant and coreactant promoters were formed in situ during pre-oxidation stage and enhanced the ECL of Au nanoclusters. A low potential step (e.g., 0 V, 5 s) was useful to activate the immobilized coreactant promoters for higher ECL enhancement ratio. The pre-oxidation enhancement strategy is valid only in the presence of anodic coreactants and Au nanoclusters. The pre-oxidation mechanism was applied in molecularly imprinted polymer (MIP) based ECL sensor, using neuron specific enolase (NSE) as the model analyte, with the detection limit of 6.3 fg mL −1 . The re-binding of the MIP film to NSE blocked the accesses between Met-AuEuNCs and TEOA in the pre-oxidation, activation and ECL measurement, decreased the ECL of Met-AuEuNCs. The pre-oxidized MIP-ECL sensor offered higher sensitivity than that in normal MIP-ECL mode without pre-oxidation and activation treatments.
危险品化学品经营许可证（带存储）