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Monitoring Protein Adsorption with Solid-state Nanopores
Published on: December 2, 2011
Probing Access Resistance of Solid-state Nanopores with a Scanning Probe Microscope Tip
Changbae Hyun1, Ryan Rollings, Jiali Li
1Physics Department, University of Arkansas, Fayetteville, AR 72701, USA.
Small (Weinheim an Der Bergstrasse, Germany)
|March 7, 2012
Summary
A new apparatus combines scanning probe microscopy with nanopore sensing to measure ionic current changes. This method probes nanopore resistance and precisely locates nanopores in solution, enabling future biomolecule detection.
Area of Science:
- Nanotechnology
- Biophysics
- Analytical Chemistry
Background:
- Solid-state nanopores are crucial for sensing applications.
- Precisely characterizing nanopore properties is essential for their effective use.
- Scanning Probe Microscopy (SPM) offers high spatial resolution.
Purpose of the Study:
- To develop an integrated apparatus combining SPM and nanopore ionic current measurement.
- To experimentally probe nanopore access resistance using an SPM tip.
- To demonstrate a method for locating nanopores in solution.
Main Methods:
- Integration of a Scanning Probe Microscope (SPM) with a solid-state nanopore.
- Measurement of ionic current blockage as a function of SPM tip position in 3D.
- Analysis of current blockage maps to determine relative pore resistance increase (ΔR/R(0)).
Main Results:
- The apparatus successfully measures current blockage and simultaneously records tip location.
- Relative pore resistance increase (ΔR/R(0)) was mapped as a function of tip position, nanopore geometry, and salt concentration.
- Experimental results align with predictions from Ohm's law, Poisson, and Nernst-Planck equations, especially at close tip proximity (~10 nm).
Conclusions:
- The developed apparatus provides an experimental method to probe nanopore access resistance.
- The technique enables precise localization of nanopores in aqueous solutions.
- This integrated approach paves the way for advanced nanopore-based single biomolecule detection.
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