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Fabrication of Electrochemical-DNA Biosensors for the Reagentless Detection of Nucleic Acids, Proteins and Small Molecules
Published on: June 1, 2011
An i-DNA based electrochemical sensor for proton detection
Xiaodong Xu1, Bo Li, Xiang Xie
1Institute of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
Talanta
|August 31, 2010
Summary
A novel electrochemical proton sensor uses ferrocene-labeled i-DNA (Fc-i-DNA) on a gold electrode. This sensor detects pH changes by measuring current variations due to Fc-i-DNA conformational shifts, offering a simple and selective method.
Area of Science:
- Biomolecular Engineering
- Electrochemistry
- Nanotechnology
Background:
- The development of precise and reliable proton (pH) sensors is crucial for various scientific and industrial applications.
- Existing pH sensing technologies often face limitations in terms of response time, selectivity, or fabrication complexity.
- Oligonucleotide-based sensors offer a promising avenue due to their specific binding properties and tunable structures.
Purpose of the Study:
- To report the development and characterization of a novel i-DNA based electrochemical proton sensor.
- To demonstrate the sensor's ability to detect pH variations through changes in electrochemical signals.
- To evaluate the sensor's performance in terms of response range, speed, selectivity, and ease of fabrication.
Main Methods:
- Fabrication of the sensor by immobilizing thiol-terminated, ferrocene-labeled i-DNA (Fc-i-DNA) onto a gold electrode surface via Au-S interaction.
- Utilizing the pH-dependent conformational switching of cytidine-rich i-DNA between random coil and i-motif structures.
- Measuring electrochemical redox currents generated by the ferrocene moiety, which vary with its distance from the electrode surface as dictated by i-DNA conformation.
Main Results:
- The Fc-i-DNA modified electrode exhibited a measurable change in redox current in response to varying solution pH.
- A linear relationship was observed between the measured currents and pH values within the range of 5.6 to 7.1.
- The developed proton sensor demonstrated a quick response time, straightforward fabrication process, and good selectivity for proton detection.
Conclusions:
- The i-DNA based electrochemical sensor provides a viable platform for sensitive and selective pH monitoring.
- The conformational changes of i-DNA in response to pH can be effectively translated into measurable electrochemical signals.
- This approach offers a promising alternative for developing advanced electrochemical sensors with potential applications in environmental monitoring, biological studies, and diagnostics.
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