| Semiconductor nanocrystals, also named quantum dots (QDs), have attracted a lot of attentions in the past few decades due to their unique optical properties and applications, which endow them as ideal optical probes used in biomedicine, biocompatibility, studying on the interaction between macromolecules, quantitative assay macromolecules and medicine and biotechnology. In this work, CdTe QDs, CdTe/CdS QDs and CdTe/ZnS QDs were synthesized in aqueous solution. The prepared CdTe QDs were characterized by transmission electron microscopy (TEM) and atomic force microscopy (AFM). The interaction between CdTe QDs and hemoglobin, heparin, anthraquinone anticancer drugs-nucleic acid was investigated by fluorescence, resonance Rayleigh scattering, ultraviolet-visible absorption spectra and chemical thermodynamics methods. The new method about determination of hemoglobin, heparin and nucleic acid was developed. The reaction mechanism between CdTe QDs and hemoglobin, heparin, anthraquinone anticancer drugs-nucleic acid was discussed in detail.1. Study on the interaction between CdTe QDs and hemoglobin by fluorescence, resonance Rayleigh scattering and absorption spectraThioglycollic acid (TGA) capped CdTe quantum dots (CdTe QDs) with the diameter of 2.8-3.2 nm were synthesized in aqueous solution. The interaction between TGA-CdTe QDs and hemoglobin (Hb) was investigated by fluorescence (FL), resonance Rayleigh scattering (RRS) and ultraviolet-visible (UV-vis) absorption spectra. The results indicated that the FL of CdTe QDs was quenched seriously by Hb via static quenching and dynamic quenching. At the same time, FL spectra of TGA-CdTe QDs hypochromatic shifted when they interacted with Hb. The formation of the binding products led to the remarkable enhancement of RRS intensity. The reasons for the enhancement of RRS intensity were discussed. The thermodynamic parametersΔHθ,ΔSθandΔGθwere obtained according to Lineweaver-Burk equations and Van't Hoff equation at different temperatures. The value ofΔGθ,ΔHθandΔSθindicated that the binding of TGA-CdTe QDs and Hb was a spontaneity and endothermic process.2. Resonance Rayleigh scattering spectral method for determination of heparin using CdTe QDs as a probeAqueous cysteamine-capped CdTe quantum dots (QDs) were prepared at a low temperature. Based on the resonance Rayleigh scattering (RRS) enhancement of cysteamine-capped CdTe QDs caused by heparin, at the same time, the intensities of second-order scattering (SOS) and frequency-doubling scattering (FDS) were also increased, a simple, rapid and quantitative method was proposed to determinate heparin. Affecting factors of RRS method for detection heparin with cysteamine-capped CdTe QDs were studied. At 311 nm, the RRS calibration plot of C/(I-Io) with concentration of heparin was linear in the range of 13.5-1000 ng/mL with correlation coefficient of 0.9991. The limit of detection (3σ) was 4.04 ng/mL. The possible reason of RRS intensity enhancement was discussed.3. A sensitive sensor for anthraquinone anticancer drugs and hsDNA based on CdTe/CdS QDs fluorescence reversible controlThioglycollic acid (TGA) capped CdTe/CdS quantum dots (CdTe/CdS QDs) were synthesized in aqueous solution. Particle sizes and morphology characteristic of TGA-CdTe/CdS QDs were studied by atomic force microscope (AFM). Based on CdTe/CdS quantum dots (CdTe/CdS QDs) fluorescence (FL) reversible control, a new FL sensor for the sensitive determination of anthraquinone (AQ) anticancer drugs (adriamycin and daunorubicin) and hsDNA in aqueous solution was developed. Under the experimental condition, FL of CdTe/CdS QDs can be effectively quenched by AQ anticancer drugs due to the binding of AQ anticancer drugs on the surface of CdTe/CdS QDs and photoinduced electron transfer (PET) process from CdTe/CdS QDs to AQ anticancer drugs. Addition of hsDNA afterwards brought the restoration of CdTe/CdS QDs FL intensity, as AQ anticancer drugs peeled off the surface of CdTe/CdS QDs and embedded into hsDNA double helix structure. The AQ anticancer drugs induced FL quenching and hsDNA induced subsequently FL restoration for CdTe/CdS QDs built a solid base for the present based FL reversible control sensor for detecting adriamycin (ADM), daunorubicin (DNR) and hsDNA. The liner ranges and the detection limits of FL quenching methods for two AQ anticancer drugs were 0.33-9μg·mL-1 and 0.09μg·mL-1 for ADM and 0.15-9μg-mL"1 and 0.04μg-mL"1 for DNR, respectively. The restored FL intensity was proportional to concentration of hsDNA in the ranges of 1.38-28μg·mL-1 and the detection limit for hsDNA was 0.41μg·mL"1. It was applied to the determination of AQ anticancer drugs in human serum and urine samples with satisfactory results. The reaction mechanism of CdTe/CdS QDs FL reversible control was studied.4. Study on the interaction between pirarubicin and ctDNA by CdTe/ZnS QDs fluorescence reversible controlGlutathione (GSH) capped CdTe quantum dots (GSH-CdTe/ZnS QDs) was synthesized in aqueous solution. Particle sizes and morphology characteristic of GSH-CdTe/ZnS QDs were studied by atomic force microscope (AFM). The results indicated that particle sizes of GSH-CdTe/ZnS QDs with narrow distribution and nice disperse was obtained. Fluorescence (FL) of GSH-CdTe/ZnS QDs can be effectively quenched by pirarubicin (THP) due to the binding of THP on the surface of GSH-CdTe/ZnS QDs and photoinduced electron transfer (PET) process from GSH-CdTe/ZnS QDs to THP. And then the addition of ctDNA brought the restoration of GSH-CdTe/ZnS QDs FL intensity, as THP peeled off the surface of GSH-CdTe/ZnS QDs and embedded into ctDNA double helix structure and PET process from GSH-CdTe/ZnS QDs to THP was prevented. According to the AQ anticancer drugs induced FL quenching and ctDNA induced subsequently FL restoration for GSH-CdTe/ZnS QDs, CdTe/CdS QDs FL reversible control was realized. The reaction of GSH-CdTe/ZnS QDs-THP-ctDNA was discussed based on FL, resonance Rayleigh scattering (RRS) and ultraviolet visible (UV-vis) absorption spectra. A spectroscopy which was used to investigate the interaction between anthraquinone anticancer drugs and DNA was developed.
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