A versatile label-free and signal-on electrochemical biosensing platform based on triplex-forming oligonucleotide probe.
Nucleic acid and protein assays are very important in modern life sciences, and the recently developed triplex-forming oligonucleotide probes provide a unique means for biological analysis of different kinds of analytes. Herein, we report a label-free and signal-on electrochemical sensor for the detection of specific targets, which is based on the triple-helix structure formation between the hairpin molecular beacon and the capture probe through the intermolecular DNA hybridization induced by Watson-Crick and Hoogsteen base pairings. Upon the introduction of a specific target, the triple-helical stem region is dissembled to liberate the hemin aptamer, and a G-quadruplex- hemin complex can be formed in the presence of K(+) and hemin on the electrode surface to give an electrochemical response, thus signaling the presence of the target. With the use of Human Immunodeficiency Virus type 1 (HIV-1) as a proof-of-principle analyte, we first demonstrated this approach by using a molecular beacon, which consists of a central section with the DNA sequence complementary to HIV-1, flanked by two arm segments. This newly designed protocol provides an ultrasensitive electrochemical detection of HIV-1 with a limit of detection down to 0.054 nM, and also exhibit good selectivity. Therefore, the as-proposed strategy holds a great potential for early diagnosis in gene-related diseases, and with further development, it could be used as a universal protocol for the detection of various DNA sequences and may be extended for the detection of aptamer-binding molecules.
College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao 266109, China.
Xiuzhong
X
Wang
College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao 266109, China.
Aiwen
A
Jiang
College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao 266109, China.
Ting
T
Hou
College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao 266109, China. Electronic address: lifeng@qust.edu.cn.
Feng
F
Li
D052157:Aptamers, Nucleotide / Q000737:chemistry; D015374:Biosensing Techniques; D055664:Electrochemical Techniques; D004566:Electrodes; D054856:G-Quadruplexes; D015497:HIV-1 / Q000235:genetics; D006427:Hemin / Q000737:chemistry; D006801:Humans; D057230:Limit of Detection; D009693:Nucleic Acid Hybridization; D015345:Oligonucleotide Probes / Q000737:chemistry* / Q000378:metabolism; D011188:Potassium / Q000737:chemistry; D012367:RNA, Viral / Q000032:analysis*
D052157:Aptamers, Nucleotide; D015345:Oligonucleotide Probes; D012367:RNA, Viral; D006427:Hemin; D011188:Potassium
Electrochemical biosensing; Label-free; Molecular beacon; Triplex formation