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Dual-color magnetic-quantum dot nanobeads as versatile fluorescent probes in test strip for simultaneous point-of-care detection of free and complexed prostate-specific antigen

Rong, Zhen, Bai, Zikun, Li, Jianing, Tang, Hao, Shen, Tianyi, Wang, Qiong, Wang, Chongwen, Xiao, Rui, Wang, Shengqi
Biosensors & bioelectronics 2019 v.145 pp. 111719
adsorption, antibodies, biosensors, blood serum, chemical species, detection limit, diagnostic techniques, fluorescence, fluorescent dyes, hyperplasia, image analysis, immunoassays, information processing, iron oxides, magnetic properties, magnetism, mobile telephones, nanoparticles, patients, point-of-care systems, prostate-specific antigen, prostatic neoplasms, quantum dots
Simultaneous detection of free and complexed prostate-specific antigen (f-PSA and c-PSA) is critical to the prostate cancer (PCa) diagnostic accuracy for clinical samples with PSA values in the diagnostic gray zone between 4 and 10 ng mL⁻¹. Herein, red and green magnetic-quantum dot nanobeads (MQBs) with superior magnetic property and high luminescence were fabricated via polyethyleneimine-mediated electrostatic adsorption of numerous quantum dots onto superparamagnetic Fe₃O₄ magnetic cores, and were conjugated with f-PSA antibody and c-PSA antibody, respectively, as versatile fluorescent probes in test strip for immune recognition, magnetic enrichment, and simultaneous detection of f-PSA and c-PSA analytes in complex biological matrix with t-PSA antibody on the test line. A low-cost and portable smartphone readout device with an application was also developed for the imaging of dual-color test strips and data processing. This assay can simultaneously detect f-PSA and c-PSA with the limits of detection of 0.009 ng mL⁻¹ and 0.087 ng mL⁻¹, respectively. Clinical serum samples of PCa and benign prostatic hyperplasia patients were evaluated to confirm the clinical feasibility. The results suggest that the proposed dual-color MQBs-based fluorescent lateral flow immunoassay is a promising point-of-care diagnostics technique for the accurate diagnosis of PCa even in resource-limited settings.