Electrophoretic Separation of Single Particles Using Nanoscale Thermoplastic Columns
Year: 2016
Type: article
Abstract: Phenomena associated with microscale electrophoresis separations cannot, in many cases, be applied to the nanoscale. Thus, understanding the electrophoretic characteristics associated with the nanoscale will help formulate relevant strategies that can optimize the performance of separations carried out on columns with at least one dimension below 150 nm. Electric double layer (EDL) overlap, diffusion, and adsorption/desorption properties and/or dielectrophoretic effects giving rise to stick/slip motion are some of the processes that can play a role in determining the efficiency of nanoscale electrophoretic separations. We investigated the performance characteristics of electrophoretic separations carried out in nanoslits fabricated in poly(methyl methacrylate), PMMA, devices. Silver nanoparticles (AgNPs) were used as the model system with tracking of their transport via dark field microscopy and localized surface plasmon resonance. AgNPs capped with citrate groups and the negatively charged PMMA walls (induced by O2 plasma modification of the nanoslit walls) enabled separations that were not apparent when these particles were electrophoresed in microscale columns. The separation of AgNPs based on their size without the need for buffer additives using PMMA nanoslit devices is demonstrated herein. Operational parameters such as the electric field strength, nanoslit dimensions, and buffer composition were evaluated as to their effects on the electrophoretic performance, both in terms of efficiency (plate numbers) and resolution. Electrophoretic separations performed at high electric field strengths (>200 V/cm) resulted in higher plate numbers compared to lower fields due to the absence of stick/slip motion at the higher electric field strengths. Indeed, 60 nm AgNPs could be separated from 100 nm particles in free solution using nanoscale electrophoresis with 100 μm long columns.
Source: Analytical Chemistry
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, F. Hoffmann-La Roche, National Institutes of Health, University of North Carolina at Chapel Hill, National Human Genome Research Institute, National Institute of Biomedical Imaging and Bioengineering, Division of Chemical, Bioengineering, Environmental, and Transport Systems, Division of Chemistry
Awards: Time-of-Flight Based Nanochannel Sensing Platforms for Real Time Bioanalysis, G4629789940, G7146208437, Polymer-Based Modular Systems with Nanosensors for DNA/RNA Sequencing, Bio-MicroElectroMechanical Systems (BioMEMS) Resource Center, Single Molecule Electrophoresis using Nanochannel Columns Fabricated in Thermoplastics, Biotechnology Resource Center of BioModular Multi-scale Systems (CBM2) for Precision Medicine
OpenAlex ID: W2296394945