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Published on: February 1, 2022
DNA electrochemical biosensor based on thionine-graphene nanocomposite
Limei Zhu1, Liqiang Luo2, Zhenxin Wang3
1College of Sciences, Shanghai University, Shanghai 200444, PR China; State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China.
A new DNA electrochemical biosensor using thionine-graphene nanocomposite offers sensitive and selective detection of complementary DNA sequences. This advanced sensor provides a low detection limit and distinguishes mismatched sequences effectively.
Area of Science:
- Electrochemistry
- Nanomaterials Science
- Molecular Biology
Background:
- Development of sensitive and selective DNA electrochemical biosensors is crucial for diagnostics.
- Graphene-based nanocomposites offer enhanced conductivity and surface area for biosensor applications.
- Thionine, as an electroactive dye, can improve signal transduction in electrochemical sensing.
Purpose of the Study:
- To develop a novel DNA electrochemical biosensor.
- To utilize a thionine-graphene nanocomposite modified gold electrode for enhanced sensing performance.
- To investigate the biosensor's sensitivity, selectivity, and detection limits for oligonucleotide detection.
Main Methods:
- Fabrication of a gold electrode modified with thionine-graphene nanocomposite.
- Characterization of the nanocomposite using scanning electron microscopy, transmission electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy.
- Covalent grafting of an amino-substituted oligonucleotide probe using glutaraldehyde.
- Monitoring hybridization via differential pulse voltammetry with daunomycin as an indicator.
Main Results:
- The thionine-graphene nanocomposite exhibited high conductivity.
- The DNA electrochemical biosensor demonstrated high sensitivity and a low detection limit (1.26 × 10(-13)M) for complementary oligonucleotides.
- A wide linear range (1.0 × 10(-12) to 1.0 × 10(-7)M) with excellent linearity (R(2)=0.9976) was achieved.
- The biosensor showed high selectivity, capable of discriminating one- or two-base mismatched sequences.
Conclusions:
- The developed DNA electrochemical biosensor based on thionine-graphene nanocomposite is highly sensitive and selective.
- The biosensor shows significant potential for accurate and reliable detection of specific DNA sequences.
- This approach offers a promising platform for developing advanced electrochemical biosensing technologies.
