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Measuring trapped DNA at the liquid-air interface for enhanced single molecule sensing
Nasim Farajpour1, Lauren S Lastra, Vinay Sharma
1Department of Bioengineering, University of California Riverside, Riverside, CA 92521, USA. kfreedman@engr.ucr.edu Kevin.freedman@ucr.edu.
Nanoscale
|March 11, 2021
Summary
Borosilicate glass nanopores offer low noise for single-molecule detection. Reducing tip submersion depth near the liquid-air interface significantly improves signal-to-noise ratio for DNA detection.
Area of Science:
- Single-molecule detection
- Nanopore sensing technology
- Biophysics
Background:
- Borosilicate glass nanopores are cost-effective and low-noise alternatives for solid-state nanopores.
- Capacitive noise in dielectric nanopores is influenced by wall thickness and submerged surface area.
- Optimizing nanopore sensing requires understanding noise contributions and environmental factors.
Purpose of the Study:
- To investigate the impact of tip submersion depth on noise and ionic conductance in borosilicate glass nanopores.
- To evaluate the performance of borosilicate nanopores for detecting lambda DNA (λ-DNA) at varying depths.
- To explore the potential of nanopore sensing for studying interfacial molecular gradients.
Main Methods:
- Systematic variation of borosilicate nanopore tip submersion depth (0–5000 μm).
- Measurement of root mean square (IRMS) noise and ionic conductance.
- Detection of single λ-DNA molecules using nanopore sensing.
Main Results:
- IRMS noise decreased as the nanopore tip approached the solution surface.
- Higher signal-to-noise ratios were achieved at reduced submersion depths, attributed to decreased capacitive noise.
- Increased DNA capture frequency was observed at the air-water interface due to evaporation effects.
Conclusions:
- Borosilicate glass nanopores exhibit reduced noise and enhanced signal-to-noise ratios near the liquid-air interface.
- Optimized submersion depth is crucial for sensitive single-molecule detection with borosilicate nanopores.
- These findings highlight the suitability of borosilicate nanopores for analyzing interfacial molecular concentration gradients, particularly for DNA.
