Changing the excitation wavelength is a simple but effective strategy to modulate the photophysical cha racteristics of colloidal quantum dots (QDs) near plasmonic nanostructures. It has been observed that the photoluminescence (PL) decay of QDs near plasmonic nanostructures differs when the excitation wavelength is varied, but the exact mechanism is still unclear today. Here, we studied the excitation wavelength dependence of the PL decay of CdSe/CdS core/shell QDs near plasmonic gold nanoparticles at the single QD level. With the aid of statistical science, we demonstrated that the PL decay of a single QD near gold nanoparticles is generally faster when the QD is excited spectrally close to the localized surface plasmon resonance of gold nanoparticles. This excitation wavelength dependence is mainly caused by the varied proportion of photons coming from biexciton emission, which is the result of different local electric field enhancement by gold nanoparticles upon excitation.
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http://dx.doi.org/10.1063/5.0089090 | DOI Listing |
Anal Methods
November 2017
Lab of Biosystem and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China.
As an important small molecule, adenosine triphosphate (ATP) plays an important role in the regulation of cell metabolism and supplies energy for various biochemical reactions in organisms. We herein developed a sensitive surface-enhanced Raman scattering (SERS) biosensor for highly specific detection of ATP using core-satellite assemblies. To construct the aptamer-based biosensor, a known ATP binding aptamer was divided into two segments.
View Article and Find Full Text PDFAnal Methods
November 2017
Anhui Key Laboratory of Chemo-Biosensing, Key Laboratory of Functional Molecular Solids, Ministry of Education, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, PR China.
A new aptamer-based surface plasmon resonance (SPR) system has been designed to detect Hg that utilizes near-infrared (NIR)-to-NIR gold nanoparticle coated NaYF:Yb,Tm,Gd up-conversion nanoparticles (AuNPs@NaYF:Yb,Tm,Gd UCNPs) as probes. The AuNPs@NaYF:Yb,Tm,Gd UCNPs were prepared and excited by near-infrared light (980 nm) which emitted at a near-infrared wavelength (808 nm) using an inexpensive infrared continuous wave laser diode. The AuNPs@NaYF:Yb,Tm,Gd UCNPs were conjugated with Hg aptamers.
View Article and Find Full Text PDFFood Chem
January 2025
Department of Food Engineering and Technology, School of Food Engineering, State University of Campinas, Campinas, SP, Brazil. Electronic address:
Threshold determination forms an integral part of sensory and consumer studies applied for product control and development. The authors examined the potential of an impedimetric electronic tongue to discriminate basic tastes and consider limitations pertaining to the sensory evaluation process. Three samples at lower, medium, and higher concentration levels of basic taste compounds were prepared and subjected to consumer studies (n = 60) using the difference from-control (DFC) test.
View Article and Find Full Text PDFBioelectrochemistry
January 2025
Tongzhou Maternal & Child Health Hospital of Beijing, No. 124, Yuqiao Middle Road, Tongzhou District, Beijing 101101 PR China. Electronic address:
Cystatin C (Cys-C) is emerging as a critical biomarker for assess gestational diabetes mellitus (GDM), a condition that significantly impacts maternal and fetal health. In this study, we developed a novel label-free electrochemical immunosensor designed for point-of-care applications, offering lower reagent consumption and rapid detection of Cys-C in pregnant women with GDM. Compared to traditional enzyme-linked immunosorbent assays (ELISA), the sensor demonstrates enhanced sensitivity, reduced reagent usage, and faster detection.
View Article and Find Full Text PDFPLoS One
January 2025
Faculty of Science and Engineering, Waseda University, Tokyo, Japan.
Gold (or electrum) in hydrothermal fluid precipitates directly from gold sulfide complex and/or partly via suspended nanoparticles. The hydrothermal fluid contains "invisible gold" that is atomically dispersed in sulfide minerals or as nanoparticles with a size of less than 10 nm. However, the contribution of these gold nanoparticles to the formation of native gold and its alloy with silver (electrum) remains unclear.
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