Precise DNA Concentration Measurements with Nanopores by Controlled Counting

Area of Science:

• Nanotechnology
• Biophysics
• Analytical Chemistry

Background:

• Solid-state nanopores are researched for measuring concentrations of clinical analytes like proteins and DNA.
• Current methods rely on analyte capture rates but face systematic errors from nanofabrication limitations.
• Variability within and between nanopores limits precision, hindering practical applications.

Purpose of the Study:

• To address the inherent variability in solid-state nanopore measurements.
• To develop a method for enhancing the reliability, accuracy, and precision of nanopore-based concentration determination.
• To enable precise single-molecule concentration measurements without stringent nanopore fabrication control.

Main Methods:

• Experimental investigation of variability in solid-state nanopore capture rates.
• Development and application of a controlled counting technique.
• Utilizing a mixture of target molecules and an internal calibrator of known concentration.
• Testing the method on linear DNA fragments.

Main Results:

• Identified significant, unmodeled variability in nanopore capture rates, both temporally and between pores.
• Demonstrated that controlled counting eliminates the need for precise control over nanopore properties (size, geometry, surface charge).
• Achieved higher-precision concentration measurements using the controlled counting method.

Conclusions:

• Inherent nanopore variability limits the precision of current concentration measurement techniques.
• Controlled counting offers a robust solution to overcome nanopore variability.
• This method significantly enhances the utility of solid-state nanopores as reliable biomolecule sensors.