期刊
BIOSENSORS & BIOELECTRONICS
卷 109, 期 -, 页码 35-42出版社
ELSEVIER ADVANCED TECHNOLOGY
DOI: 10.1016/j.bios.2018.02.059
关键词
Four-way junction; Electrochemical impedance spectroscopy; Label-free; Universal sensor
类别
资金
- NSF-nanobiosensing grant [1706802]
- Florida Health Department at the University of Central Florida [7ZK05]
- College of Sciences at the University of Central Florida
- Department of Chemistry at the University of Central Florida
- NSF CCF grants [1117205, 1423219]
- NIH [R15AI10388001A1]
- ITMO University [R15AI10388001A1]
- Division of Computing and Communication Foundations
- Direct For Computer & Info Scie & Enginr [1423219] Funding Source: National Science Foundation
- Div Of Chem, Bioeng, Env, & Transp Sys
- Directorate For Engineering [1706802] Funding Source: National Science Foundation
We report a label-free universal biosensing platform for highly selective detection of long nucleic acid strands. The sensor consists of an electrode-immobilized universal stem-loop (USL) probe and two adaptor strands that form a 4J structure in the presence of a specific DNA/RNA analyte. The sensor was characterized by electrochemical impedance spectroscopy (EIS) using K-3[Fe(CN)(6)]/K-4[Fe(CN)(6)] redox couple in solution. An increase in charge transfer resistance (R-CT) was observed upon 4J structure formation, the value of which depends on the analyte length. Cyclic voltammetry (CV) was used to further characterize the sensor and monitor the electrochemical reaction in conjunction with thickness measurements of the mixed DNA monolayer obtained using spectroscopic ellipsometry. In addition, the electron transfer was calculated at the electrode/electrolyte interface using a rotating disk electrode. Limits of detection in the femtomolar range were achieved for nucleic acid targets of different lengths (22 nt, 60 nt, 200 nt). The sensor produced only a background signal in the presence of single base mismatched analytes, even in hundred times excess in concentration. This label-free and highly selective biosensing platform is versatile and can be used for universal detection of nucleic acids of varied lengths which could revolutionize point of care diagnostics for applications such as bacterial or cancer screening.
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