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Gold nanoparticle translocation dynamics and electrical detection of single particle diffusion using solid-state
Gaurav Goyal1, Kevin J Freedman, Min Jun Kim
1School of Biomedical Engineering, Science and Health Systems, Drexel University, 3141 Chestnut Street, Philadelphia, Pennsylvania 19104, USA.
Analytical Chemistry
|July 27, 2013
Summary
Researchers used gold nanoparticles in solid-state nanopores to observe particle movement. A counterion cloud effect enhances current during translocation, enabling sensitive detection of diffusion events for biomolecule analysis.
Area of Science:
- Nanotechnology
- Surface Science
- Electrochemistry
Background:
- Solid-state nanopores offer precise control over ion flow.
- Particle translocation through nanopores is a key phenomenon in sensing.
- Understanding ion cloud effects is crucial for nanopore sensing accuracy.
Purpose of the Study:
- To investigate gold nanoparticle translocation dynamics through silicon nitride nanopores.
- To elucidate the mechanism behind current enhancement during particle translocation.
- To assess the potential of nanopore sensors for field-free biomolecule diffusion analysis.
Main Methods:
- Utilizing silicon nitride solid-state nanopores.
- Dispersing gold nanoparticles in a low-concentration KCl solution with Triton X-100.
- Applying varying voltages to study translocation events.
- Recording single particle diffusion at zero voltage bias.
Main Results:
- Observed current enhancement during gold nanoparticle translocation.
- Attributed current enhancement to the nanoparticle's associated counterion cloud increasing ion density.
- Achieved high signal-to-noise ratio detection of single particle diffusion events.
- Demonstrated nanopore sensing capability at near-physiological salt concentrations.
Conclusions:
- The counterion cloud significantly influences ion transport during nanopore translocation.
- Nanopore sensors can detect single particle diffusion with high sensitivity.
- This technique shows promise for analyzing biomolecules in their native states without external fields.
