We report here a novel strategy for the high-sensitive detection of target biomolecules with very low concentrations on a quartz crystal microbalance (QCM) device using gold nanoparticles as signal enhancement probes. By employing a streptavidin-biotin interaction as a model system, we could prepare biotin-conjugated gold nanoparticles maintaining good dispersion and long-term stability by controlling the biotin density on the surface of gold nanoparticles that have been investigated by UV-vis spectra and AFM images. These results showed that 10 microM N-(6-[biotinamido]hexyl)-3'-(2'-pyridyldithio)propionamide (biotin-HPDP) was the critical concentration to prevent the nonspecific aggregation of gold nanoparticles in this system. For sensing streptavidin target molecules by QCM, biotinylated BSA was absorbed on the Au surface of the QCM electrode and subsequent coupling of the target streptavidin to the biotin in the sensing interface followed. Amplification of the sensing process was performed by the interaction of the target streptavidin on the sensing surface with gold nanoparticles modified with 10 microM biotin-HPDP. The biotinylated gold nanoparticles were used as signal amplification probes to improve the detection limit, which was 50 ng/ml, of the streptavidin detection system without signal enhancement, and the calibration curve determined for the net frequency changes showed good linearity over a wide range from 1 ng/ml to 10 microg/ml for the quantitative streptavidin target molecule analysis. In addition, the measured dissipation changes suggested that the layer of biotin-BSA adsorbed on the Au electrode and the streptavidin layer assembled on the biotin-BSA surface were highly compact and rigid. On the other hand, the structure formed by the biotinylated gold nanoparticles on the streptavidin layer was flexible and dissipative, being elongated outward from the sensing surface.
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http://dx.doi.org/10.2116/analsci.23.177 | 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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