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Nanoparticles for Bioapplications: Study of the Cytotoxicity of Water Dispersible CdSe(S) and CdSe(S)/ZnO Quantum Dots
摘要： Semiconductor nanocrystals or quantum dots (QDs) have unique optical and physical properties that make them potential imaging tools in biological and medical applications. However, concerns over the aqueous dispersivity, toxicity to cells, and stability in biological environments may limit the use of QDs in such applications. Here, we report an investigation into the cytotoxicity of aqueous dispersed CdSe(S) and CdSe(S)/ZnO core/shell QDs in the presence of human colorectal carcinoma cells (HCT-116) and a human skin fibroblast cell line (WS1). The cytotoxicity of the precursor solutions used in the synthesis of the CdSe(S) QDs was also determined in the presence of HCT-116 cells. CdSe(S) QDs were found to have a low toxicity at concentrations up to 100 μg/mL, with a decreased cell viability at higher concentrations, indicating a highly dose-dependent response. Meanwhile, CdSe(S)/ZnO core/shell QDs exhibited lower toxicity than uncoated QDs at higher concentrations. Confocal microscopy images of HCT-116 cells after incubation with CdSe(S) and CdSe(S)/ZnO QDs showed that the cells were stable in aqueous concentrations of 100 μg of QDs per mL, with no sign of cell necrosis, confirming the cytotoxicity data.
关键词： core/shell QDs,HCT-116,water dispersive QDs,WS1,bioapplications of QDs,aqueous synthesis,in vitro cytotoxicity of QDs
更新于2025-11-21 11:08:12
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Sandwich magnetically imprinted immunosensor for electrochemiluminescence ultrasensing diethylstilbestrol based on enhanced luminescence of Ru@SiO2 by CdTe@ZnS quantum dots
摘要： A molecularly imprinted magnetic sensor with electroluminescent tags (MIP-ECL sensor) was developed for ultrasensing diethylstilbestrol (DES). A strategy is exploited to enhance ECL emission of the [Ru(bpy)3]2 +-tripropyl amine (TPrA) system by CdTe@ZnS quantum-dots (QDs) through energy transfer. Magnetically molecularly imprinted nanoparticles (MMIPs NPs) based on Fe3O4@SiO2 carriers are artificial, easily reproducible, and could replace easily inactivated first antibodies for capturing more DES molecules. Functionalized bio-conjugates of single antibody-CdTe@ZnS (Ab-CdTe@ZnS) are for the first time loaded on signal labels of Ru(bpy)3 2 +-doped silica nanocomposites (Ru@SiO2) for signal amplification. The final bio-conjugated signal probes are denoted as Ab-DES/CdTe@ZnS-Ru@SiO2. MMIPs beads that have captured antigens are bio-conjugated with antibody-labeled luminescent probes by specific immunoreactive reaction, and then the luminescent immunocomplex generates ECL signal on the magnetic electrode. The logarithm of ECL intensities depend linearly on the logarithm of DES concentrations in the range from 4.8×10? 4 to 36.0 nM with a detection limit of 0.025 pM. This novel assay is much more sensitive than other MIP sensors, and achieves lower cost and more enhanced stability than other immunosensors. The sensor is significantly potential and has been applied to DES detection in actual environment.
关键词： [Ru(bpy)3]2+-doped silica,Probe-mode ECL sensor,Core-shell QDs,Magnetically imprinted nanoparticles,Diethylstilbestrol,Single antibody sandwich-type
更新于2025-09-23 15:19:57
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ZnSe/ZnS Core/shell Quantum Dots with Superior Optical Properties through Thermodynamic Shell Growth
摘要： Epitaxial growth of a protective semiconductor shell on a colloidal quantum dot (QD) core is the key strategy for achieving high fluorescence quantum efficiency and essential stability for optoelectronic applications and bio-tagging with emissive QDs. Herein we investigate the effect of shell growth rate on the structure and optical properties in blue-emitting ZnSe/ZnS QDs with narrow emission linewidth. Tuning the precursor reactivity modifies the growth mode of ZnS shells on ZnSe cores transforming from kinetic (fast) to thermodynamic (slow) growth regimes. In the thermodynamic growth regime, enhanced fluorescence quantum yields and reduced on-off blinking are achieved. This high performance is ascribed to the effective avoidance of traps at the interface between the core and the shell, which are detrimental to the emission properties. Our study points to a general strategy to obtain high-quality core/shell QDs with enhanced optical properties through controlled reactivity yielding shell growth in the thermodynamic limit.
关键词： thermodynamic,core/shell QDs,heavy-metal-free,ZnSe/ZnS,kinetic
更新于2025-09-19 17:13:59
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Detection of lead Using Thioglycolic Acid Capped ZnSe and ZnSe@ZnS core-shell Quantum Dots
摘要： Herein, we proffer a sensitive and selective sensor using ZnSe and ZnSe@ZnS quantum dots (QDs), for detection of toxic metal ions at nm level. It has been found that the TGA capped ZnSe and ZnSe@ZnS QDs were apparently sensitive to Pb2+ ions as perceptible from their fluorescence quenching measurements. However, in case of few common heavy metal ions such as Zn2+, Co2+, Fe2+, , Mg2+, Cu2+, Ni2+ and Cd2+ ions, negligible quenching compared to Pb2+ ions was noted. Hence, we have successfully detected Pb2+ ions in aqueous solutions based on the photoluminescence (PL) spectroscopy. The observed linearity range was from 10 NM to 100 nM for both Pb2+ ions. An alternative QD based sensor for the spectroscopic detection, and concentration quantification of Pb2+ ions is proposed.
关键词： Metal ions,Photoluminescence,Thioglycolic acid,Quantum dots,Core-shell QDs
更新于2025-09-12 10:27:22