科研之友
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摘要
Lowering the detection limit is critical to the design of,, bioassays required for medical diagnostics environmental monitoring, and food, safety regulations. The current sensitivity of standard, color-based analyte detection limits the further use Of enzyme-linked immunosorbent, assays (ELISAs) in research and clinical diagnoses. Here; we demonstrate a novel method that uses the Raman signal as the signal-generating system of an ELISA and combines surface-enhanced Raman scattering (SERS) with, silver nanoparticles aggregation for ultrasensitive analyte detection. The enzyme label of the ELISA controls the dissolution of Raman reporter-labeled silver nanoparticles: through hydrogen peroxide and generates strong Raman signal when the analyte is present. Using this assay, prostate-specific antigen (PSA) and the adrenal stimulant ractopamine (Rac), were detected in whole serum: and urine at the ultralow concentrations of 10(-9) and 10(-6) ng/mL, respectively. The methodology proposed here could potentially be applied to other molecules detection as well as PSA and Rac.
