Competitive aptasensor for the ultrasensitive multiplexed detection of cancer biomarkers by fluorescent nanoparticle counting

• Published in: Analyst (London) 2020-05, Vol.145 (1), p.3612-3619
• Main Authors: Pei, Xiaojing, Wu, Xi, Xiong, Jie, Wang, Guohong, Tao, Guangyu, Ma, Yurou, Li, Na
• Format: Article
• Language: English
• Subjects: Antigens; Aptamers, Nucleotide - genetics; Aptamers, Nucleotide - metabolism; Base Sequence; Biomarkers; Biomarkers, Tumor - analysis; Biomarkers, Tumor - blood; Biomarkers, Tumor - metabolism; Biosensing Techniques - methods; Business competition; Cancer; Deoxyribonucleic acid; Diagnosis; DNA; Fluorescence; Fluorescent Dyes - chemistry; Humans; Limit of Detection; Multiplexing; Nanocomposites; Nanoparticles; Nanoparticles - chemistry
• ISSN: 0003-2654; 1364-5528
• DOI: 10.1039/d0an00239a

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. Multiplexed detection by fluorescent nanoparticle counting based on competitive mode.