Dementia and Geriatric Cognitive Disorders Extra (May 2022)

Effect of Time to Detection on the Measured Concentrations of Blood Proteins Associated with Alzheimer’s Disease

  • Hsin-Hsien Chen,
  • Chia-Shin Ho,
  • Ming-Hung Hsu,
  • Yu-Chen Lin,
  • Jui-Feng Chang,
  • Shieh-Yueh Yang

DOI
https://doi.org/10.1159/000515072
Journal volume & issue
Vol. 12, no. 2
pp. 82 – 89

Abstract

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Background: For assays using immunomagnetic reduction, a reagent composed of antibody-functionalized magnetic nanoparticles is dispersed in phosphate-buffered saline solution. The real-time signals of alternating-current (ac) magnetic susceptibility, χac, of the reagent are subsequently recorded after mixing the reagent with a biofluid sample. After mixing the reagent and sample, the reduction in χac of the mixture is calculated and used to quantify the concentration of the target biomarker in the sample. The reduction does not occur immediately but rather occurs at some time after mixing. This observation implies that the time elapsed before recording the real-time signals of χac of a reagent-sample mixture needs to be investigated to ensure that the signals are fully recorded. In this work, the effect of time to detection on the measured concentrations of proteins in human plasma after mixing the reagent and sample is examined. Methods: The proteins analyzed are related to Alzheimer’s disease: amyloid β 1–40, amyloid β 1–42, and Tau protein. The investigated times to detection after the mixing the reagent and sample are 0, 20, 30, 40, and 120 min. Results: The results show that the recording of real-time signals of χac should be conducted within 20 min after mixing the reagent and sample.

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