Pei X, Wu X, Xiong J, Wang G, Tao G, Ma Y, Li N. Competitive aptasensor for the ultrasensitive multiplexed detection of cancer biomarkers by fluorescent nanoparticle counting.
Analyst 2020;
145:3612-3619. [PMID:
32285061 DOI:
10.1039/d0an00239a]
[Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Cancer biomarker quantification in human serum is of great importance for accurate patient diagnosis and informed clinical management. To date, ultrasensitive multiplexed detection of proteins without amplification is still a major challenge. Herein, we proposed a competitive aptasensor strategy for ultrasensitive multiplexed cancer biomarker detection by fluorescent nanoparticle (FNP) counting. The sequences are designed such that the binding abilities of linker DNA (L-DNA) with DNA-functionalized FNPs (DNA-FNPs) and aptamer are comparable. As long as one target binds with one molecule of aptamer, a signalling FNP forms a sandwich-structured nanocomposite, which was subsequently observed and enumerated with a fluorescence microscope. This 1 : 1 target-to-signal FNP production assured an improved sensitivity, benefiting from the reasonably good brightness and photostability of FNPs. For both singleplexed and multiplexed detection, this proposed strategy achieved an approximately 1000-fold improved limit of detection than the conventional method with the detection volume of 3.2 μL. Notably, the results for carcinoembryonic antigen (CEA) detection obtained directly from 9 human serum samples (colorectal/lung/healthy individuals) were consistent with that obtained by ELISA, showing potential application in clinical diagnosis.
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