DNA-mediated strand displacement facilitates sensitive electronic detection of antibodies in human serums.
We describe here the development of a sensitive and convenient electronic sensor for the detection of antibodies in human serums. The sensor is constructed by self-assembly formation of a mixed monolayer containing the small molecule epitope conjugated double stranded DNA probes on gold electrode. The target antibody binds the epitope on the dsDNA probe and lowers the melting temperature of the duplex, which facilitates the displacement of the antibody-linked strand of the duplex probe by an invading methylene blue-tagged single stranded DNA (MB-ssDNA) through the strand displacement reaction and leads to the capture of many MB-ssDNA on the sensor surface. Subsequent electrochemical oxidation of the methylene blue labels results in amplified current response for sensitive monitoring of the antibodies. The antibody assay conditions are optimized and the sensor exhibits a linear range between 1.0 and 25.0nM with a detection limit of 0.67nM for the target antibody. The sensor is also selective and can be employed to detect the target antibodies in human serum samples. With the advantages of using small molecule epitope as the antibody recognition element over traditional antigen, the versatile manipulability of the DNA probes and the unique properties of the electrochemical transduction technique, the developed sensor thus hold great potential for simple and sensitive detection of different antibodies and other proteins in real samples.
Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
Baoting
B
Dou
Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
Jianmei
J
Yang
Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
Kai
K
Shi
Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China.
Ruo
R
Yuan
Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, PR China. Electronic address: yunatswu@swu.edu.cn.
Yun
Y
Xiang
D000906:Antibodies / Q000032:analysis / Q000097:blood*; D015374:Biosensing Techniques / Q000379:methods; D015342:DNA Probes / Q000737:chemistry*; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D006046:Gold / Q000737:chemistry; D006801:Humans; D057230:Limit of Detection; D008751:Methylene Blue / Q000737:chemistry; D009690:Nucleic Acid Conformation; D009691:Nucleic Acid Denaturation
D000906:Antibodies; D015342:DNA Probes; D006046:Gold; D008751:Methylene Blue
Antibody detection; Electrochemical; Human serum; Strand displacement