Cadmium sulfide (CdS) quantum dots (QDs) were homogeneously embedded into chitosan (CTS), denoted as CdS@CTS, via an in situ hydrothermal method. The intact structure of the synthesized materials was preserved using freeze-drying. The materials were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy, transmission electron microscopy, high-resolution TEM, scanning TEM, dispersive energy X-ray (EDX) for elemental analysis and mapping, Fourier transform infrared spectroscopy, nitrogen adsorption-desorption isotherms, thermogravimetric analysis, UV-vis spectroscopy, and diffuse reflectance spectroscopy (DRS). The synthesis procedure offered CdS QDs of 1-7 nm (average particle size of 3.2 nm). The functional groups of CTS modulate the in situ growth of CdS QDs and prevent the agglomeration of CdS QDs, offering homogenous distribution inside CTS. CdS@CTS QDs can also be used for naked-eye detection of heavy metals with high selectivity toward copper (Cu) ions. The mechanism of interactions between Cu ions and CdS@CTS QDs were further studied.
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http://dx.doi.org/10.1021/acsomega.2c01793 | DOI Listing |
J Phys Chem A
December 2024
Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States.
Time-resolved single molecule localization microscopy (TR-SMLM) with a 2 × 2 pixel fiber optic array camera was combined with time-correlated single photon counting (TCSPC) to obtain super-resolved fluorescence lifetime images of individual Cy3 dye molecules and individual colloidal CdSe/CdS/ZnS core/shell/shell semiconductor quantum dots (QDs). The characteristic blinking and bleaching behavior of the Cy3 and the blinking behavior of the QD emitters were used as distinguishing optical characteristics to isolate them and determine their centroid locations with spatial resolution below the optical diffraction limit. TCSPC was used to characterize the fluorescence lifetime and intensity corresponding to each emitter location.
View Article and Find Full Text PDFSensors (Basel)
December 2024
College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
Food safety is of great concern, and food-borne bacterial infections and diseases are a major crisis for health. Therefore, it is necessary to develop rapid detection techniques for the prevention and recognition of food safety hazards caused by food-borne pathogens. In recent years, the fluorescence assay has become a widely utilized detection method due to its good signal amplification effect, high detection sensitivity, high stability, and short detection time.
View Article and Find Full Text PDFTalanta
December 2024
School of Chemistry and Materials Science, Jiangsu Normal University, Xuzhou, 221116, China.
A novel dual-mode electrochemiluminescence (ECL)/photoelectrochemistry (PEC) biosensor was developed for sensitive serotonin detection. In this system, the PEC signal was produced by CdS quantum dots (QDs), while the ECL signal originated from L-Au NPs (luminol decorated Au nanoparticles), thereby avoiding the external interference and signal fluctuations that typically arose from using the same materials for both signals. The presence of target serotonin initiated the non-enzymatic toehold-mediated strand displacement reaction (TSDR) on magnetic bead (MB), which was followed by catalytic hairpin assembly (CHA) on the sensing interface, leading to the aggregation of many L-Au NPs.
View Article and Find Full Text PDFLuminescence
December 2024
School of Biotechnology, KIIT University, Bhubaneswar, Odisha, India.
This study presents a mild, one-pot synthetic approach for the synthesis of multicolor, water soluble, photo luminescent CdS and CdSe quantum dots (QDs). To achieve this goal, cyclic peptides containing cysteine residues are rationally designed and synthesized. Among the peptides tested, those containing two cysteine residues exhibit superior stabilizing properties, ensuring the solubility and long-term stability of the QDs in aqueous solutions for several months.
View Article and Find Full Text PDFAnal Chem
December 2024
School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, PR China.
Organic photoelectrochemical transistor (OPECT) assays are mainly focused on the improvement of photoactive materials at the gating interface, which leads to an enhanced initial signal alongside significant background noise. This phenomenon can cause considerable deviations and impose limits on target detection. In this study, we achieved sensitive and low-background detection of alkaline phospholipase (ALP) activity using single-stranded DNA (ssDNA) as a nanocarrier to effectively immobilizing CdS quantum dots (QDs) sensitizing UiO-66.
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