Capacitive biosensor for quantification of trace amounts of DNA

Area of Science:

• Biosensor technology
• Molecular biology
• Biochemistry

Background:

• DNA detection is crucial in various fields, including diagnostics and food safety.
• Existing methods for trace DNA detection can be complex and time-consuming.
• Developing sensitive and rapid DNA detection systems is an ongoing challenge.

Purpose of the Study:

• To develop a flow injection capacitive biosensor for trace DNA detection.
• To investigate the affinity binding between immobilized histones and DNA.
• To evaluate the biosensor's performance for different DNA sources and in real-world samples.

Main Methods:

• Immobilization of calf thymus and shrimp histones on gold electrodes using self-assembled monolayers (SAM) of thioctic acid.
• Detection of DNA from calf thymus, shrimp, and Escherichia coli using a flow injection capacitive biosensor.
• Analysis of standard curves, detection limits, and reproducibility.
• Application of the biosensor for residual DNA analysis in crude protein extracts.

Main Results:

• Histones exhibited preferential binding to DNA from the same source, leading to higher sensitivity.
• A low detection limit of 10(-5) ng/L was achieved for DNA from various sources.
• The biosensor demonstrated good reproducibility (up to 43 cycles with %R.S.D. of 3.1) and stability.
• Successful application in analyzing residual DNA in white shrimp protein extracts with recoveries between 80% and 116%.

Conclusions:

• The developed flow injection capacitive biosensor system effectively detects trace amounts of DNA.
• Histone-DNA affinity is a viable basis for sensitive and selective DNA detection.
• The biosensor shows potential for applications in food safety and other areas requiring DNA analysis.