Quantification of DNA through a fluorescence biosensor based on click chemistry

Area of Science:

• Biochemistry
• Analytical Chemistry
• Nanotechnology

Background:

• Accurate DNA detection is crucial for diagnostics.
• Existing methods may lack sensitivity or selectivity.
• Nanomaterials offer potential for enhanced biosensing.

Purpose of the Study:

• To develop a simple, sensitive, and selective fluorescence biosensor for DNA determination.
• To utilize copper sulfide (CuS) nanoparticles and click chemistry for DNA detection.
• To demonstrate the sensor's efficacy using hepatitis B virus DNA as a model.

Main Methods:

• A sandwich-like structure was formed using biotin-modified capture DNA on magnetic beads, target DNA, and DNA-CuS particles.
• CuS particles were acid-lysed to Cu(II), reduced to Cu(I) by sodium ascorbate.
• Cu(I) catalyzed a click chemistry reaction to form a fluorescent triazole compound.

Main Results:

• Target DNA concentration was determined by fluorescence intensity changes.
• A linear relationship was observed between fluorescence and the logarithm of DNA concentration (0.1–100 nM).
• The detection limit was as low as 0.04 nM (S/N = 3).

Conclusions:

• The developed fluorescence biosensor is highly sensitive, reproducible, and selective.
• The sensor demonstrates excellent selectivity, even for single-nucleotide mismatches.
• This click chemistry-based approach using CuS nanoparticles provides a promising method for DNA detection.