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Early detection of cancer is helpful for the control and prevention of diseases. Due to the low content of cancer biomarkers in the early disease phases, however, an ultrasensitive and selective method is critical. In this contribution, an ultrasensitive surface-enhanced Raman scattering (SERS) immunoassay is newly developed with the principle of introducing a common enzyme-induced deposition (EID) reaction to coat a silver layer on the surface of gold nanoparticles and to form a core-shell nanostructure of Au@Ag. By using alkaline phosphatase (ALP) to dephosphorylate its substrate, 2-phospho-l-ascorbic acid trisodium salt (AAP), to form vitamin C, silver ions could be reduced into silver atoms and coated on the surface of the AuNPs; a greatly enhanced SERS signal was then obtained. As a proof of concept, α-fetoprotein (AFP) was detected as a target, which is a biomarker of liver cancer. Excellent analytical performance of the SERS immunoassay could be achieved in the range from 0.5 to 100 pg mL with a limit of detection of 0.081 pg mL (3σ). Identical results could be obtained by using the newly proposed SERS immunoassay for the clinical detection of AFP in serum samples of patients to those clinically obtained by chemiluminescence immunoassays, demonstrating the potential applications of the developed method in clinical diagnosis.
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http://dx.doi.org/10.1039/c6nr07979b | DOI Listing |
Anal Chem
August 2025
State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P. R. China.
Studying the characteristics of T cell activation and cytokine secretion is crucial for understanding the cell-mediated immunological response (CMI). To assess this purpose, we present a droplet-based single-cell immunoassay platform, named Drop-SCIA, which uniquely integrates surface-enhanced Raman spectroscopy (SERS) with homogeneous-phase immunoassay, enabling highly sensitive, multiplexed cytokine detection at the single-cell level and offering superior target enrichment efficiency compared to the widely used interface-based ELISpot assay. Using this platform, we analyzed Jurkat T cell activation and further profiled IL-2 and IFN-γ secretion following coculture with normal breast epithelial cells (MCF-10A) and breast cancer subtypes (MCF-7, MDA-MB-231).
View Article and Find Full Text PDFAppl Spectrosc
August 2025
Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA.
This paper reports on the application of infrared external reflection spectroscopy (IR-ERS) to the characterization of small surface area addresses prepared on smooth gold surfaces after modification for use as capture substrates in sandwich immunoassays based on surface-enhanced Raman scattering (SERS). Most of the past work with IR-ERS on analyzing coatings formed on highly reflective metals utilized relatively large area samples (e.g.
View Article and Find Full Text PDFBiosens Bioelectron
November 2025
State Key Laboratory of Digital Medical Engineering, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 211189, China; Southeast University-Monash University Joint Graduate School, Suzhou, 215123, China. Electroni
Nanoengineering of plasmonic/magnetic nanocrystals plays a pivotal role in advancing biomolecular detection, offering emerging strategies for cancer diagnostics and therapeutic monitoring. Early and precise detection of cancer biomarkers is critical for timely intervention. Yet conventional immunoassays are often hindered by limited sensitivity, nonspecific binding, and inefficient target enrichment, reducing their clinical reliability.
View Article and Find Full Text PDFNanoscale
August 2025
Department of Electrical Engineering and Electronics, University of Liverpool, UK.
Cortisol plays a central role in maintaining physiological homeostasis, and both cortisol excess and deficiency are associated with life-threatening conditions. Accurate diagnosis, adequate treatment and monitoring of disorders of cortisol secretion are essential for good health, normal growth and development. Although commercially available lateral flow immunoassay (LFI) strips can be used to measure cortisol, they have limitations, especially low sensitivity and limited quantitative performance, inhibiting their use in clinical settings.
View Article and Find Full Text PDFSensors (Basel)
July 2025
N. M. Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, 4 Kosygina Str., 119334 Moscow, Russia.
Galactomannan (GM) is a polysaccharide secreted by opportunistic pathogenic fungi of the Aspergillus genus. It is prescribed as a diagnostic biomarker of invasive aspergillosis in immunocompromised patients by the guidelines for diagnosis and management of Aspergillus diseases. It has been shown previously that the measurement of soluble horseradish peroxidase (HRP) using surface-enhanced Raman scattering (SERS) of 2,3-diaminophenazine enzymatic reaction product on silver nanoparticles is largely superior in detection limit compared to colorimetric readout.
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