Controlled Synthesis,Luminescent Properties And Biological Applications Of CuInS₂ Quantum Dots Nanoprobes

In this thesis,we mainly focus on the controlled synthesis of CuInS₂ quantum dots（QDs）and the regulation of their luminescence properties.Moreover,their applications for in vitro detection and biological cell imaging were also demonstrated.The main contents are as follows:（1）The monodisperse CuInS₂:Zn²⁺QDs with particle size spanning from 2.2 nm to29.6 nm were successfully prepared via ion exchange method by changing the Zn/In ratio or Cu/In ratio.Their optical properties were studied systematically.Upon excitation at365 nm,the photoluminescent（PL）emission wavelength can be tuned from 522 to 678nm,with the highest PL quantum yield of 28.6%.The PL mechanism of CuInS₂:Zn²⁺QDs with Cu/In（8.9 mol%）was further analyzed by measuring the temperature-dependent PL spectra.（2）Lanthanide ions doped CuInS₂ nanocrystals were synthesized through cation exchange method or Zn²⁺co-doping strategy,respectively.The doping of lanthanide ions in CuInS₂ quantum dots was verified via PL spectra and element analyses.By changing the doping content of lanthanide ions and other reaction conditions,the sensitization effect of CuInS₂ or Cu-Zn-In-S nanocrystals on lanthanide ions(e.g.,Yb³⁺and Eu³⁺)was systematically studied.（3）CuInS₂ QDs were used as fluorescence nanoprobes for biological detection in vitro after modification with glutathione（GSH）.Because of the strong coordination between Ce³⁺and GSH on the surface of CuInS₂ QDs,the aggregation of QDs led to the PL quenching of CuInS₂ QDs.ATP was added to compete with GSH to coordinate with Ce³⁺,which resulted in the recovery of fluorescence of CuInS₂ QDs.The concentration of ATP was correlated with the PL intensity of Ce³⁺-CuInS₂ QDs.（4）The strategy of ATP-activated disassembly of Ce³⁺-conjugated CuInS₂ NCs with turn-on PL offers great promise for applications in ATP-targeted cancer cell imaging due to the high ATP level in cancer cells.The water-soluble CuInS₂ QDs were demonstrated to exhibited good biocompatibility.In order to demonstrate their application in bioimaging,Ce³⁺-conjugated CuInS₂ QDs were incubated with human embryo lung fibroblasts（HELF）cells and human cervical cancer（HeLa）cells under otherwise identical conditions.Upon excitation at 365 nm,weak PL emissions were observed from HELF cells by means of confocal laser scanning microscopy.By contrast,bright green and red signals were observed from HeLa cells.These results demonstrate that Ce³⁺-conjugated CuInS₂ NCs may be explored as feasible luminescent bioprobes to monitor the ATP level in cancer cells.