Synthesis Of Low-Toxic Quantum Dots And Their Applications

In the last decades, quantum dots (Qdots) have been widely studied due to their outstanding fluorescence property. The bioapplication of Qdots may be limited, because the photo-oxidation can cause the release of heavy metal ions, which decreases the stability and results in the cytotoxicity. Thus, the synthesis of Qdots with low-toxicity, good water solubility and high luminescence is of great significance.Electrochemiluminescence (ECL) is a newly developed technology on the basis of chemical luminescence(CL), which is a combination of both CL and electrochemistry(EC). In addition to the characteristics of CL and EC, it also presents some unique advantages, such as high sensitivity and selectivity, wide linear range, anti-interference ability, good reproducibility, excellent controllability and simple operation.Thus, based on the current developments of Qdots of our group, we explored the synthesis of low-toxic quantum dots and their application in photoluminescence and ECL. The major contents are described as follows:1. Microwave-assisted synthesis of highly luminescent CdSeTe@ZnS-SiO2quantum dots and their application in the detection of Cu(II)The CdSeTe@ZnS-SiO2Qdots (HQdots) were fabricated by a microwave-assisted method for the first time. The ZnS and SiO2could passivate the surface of Qdots and decrease the cytotoxicity. Meanwhile, the ZnS doped SiO2shell prevented a lattice constant mismatch between the core and clusters, while the ZnS-clusters donated energy to the CdSeTe through long-range resonance transfer (LRRT). The as-prepared HQdots showed high photoluminescence, low toxicity and good water solubility. The microwave-assistance method can greatly shorten the reaction time and increase the fluorescence intensity. A strongly selective quenching by Cu2+ions was detected, thus HQdots could be used in the detection of Cu2+. All of these properties show that the HQdots can be widely applied in biosensing and imaging.2. Electrochemiluminescence of bovine serum albumin-stabilized Au nanoclusters and graphene/Au nanoclusters hybrid and their applicationECL emission was observed from the low toxic bovine serum albumin-stabilized Au nanoclusters (BSA-Au NCs) and graphene/Au nanoclusters hybrid (g/Au NCs). The ECL mechanism was carefully studied. A simple label-free method for the detection of dopamine has been developed based on the ECL of BSA-Au NCs in aqueous media, while the g/Au NCs were used in the determination of hydrogen peroxide.