DNAzyme Sensor for the Detection of Ca²⁺ Using Resistive Pulse Sensing

Area of Science:

• Biochemistry
• Nanotechnology
• Analytical Chemistry

Background:

• DNAzymes are catalytic DNA molecules with potential as biosensors.
• Existing methods for detecting metal ions can be complex and time-consuming.
• Sensing strategies often rely on monitoring structural changes in DNAzymes upon target binding.

Purpose of the Study:

• To develop a simple, rapid, and sensitive method for detecting calcium ions (Ca2+) using DNAzymes.
• To utilize resistive pulse sensing (RPS) to monitor DNAzyme activity.
• To demonstrate the application of this sensor for real-world water sample analysis.

Main Methods:

• Functionalization of nanoparticles with a Ca2+-specific DNAzyme.
• Monitoring DNA cleavage and conformational changes using resistive pulse sensors (RPS).
• Assessing sensor performance with varying incubation times and Ca2+ concentrations.

Main Results:

• The Ca2+ DNAzyme sensor showed a linear response between 1-9 μm Ca2+ within 30 minutes.
• Extended incubation to 60 minutes enabled detection of Ca2+ as low as 0.3 μm.
• The sensor demonstrated high specificity for Ca2+ in the presence of other metal ions.
• Quantification of Ca2+ in tap and pond water samples was successful.

Conclusions:

• Resistive pulse sensing provides a rapid and effective platform for monitoring DNAzyme-based reactions.
• This Ca2+ DNAzyme sensor offers a sensitive, specific, and practical tool for ion detection.
• The developed method has potential for environmental monitoring and other applications requiring Ca2+ quantification.