Surface charge, electroosmotic flow and DNA extension in chemically modified thermoplastic nanoslits and nanochannels.

Citation data:

The Analyst, ISSN: 1364-5528, Vol: 140, Issue: 1, Page: 113-26

Publication Year:
2015
Usage 20
Abstract Views 20
Captures 49
Readers 36
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Citations 23
Citation Indexes 23
Repository URL:
http://scholarworks.unist.ac.kr/handle/201301/9782
PMID:
25369728
DOI:
10.1039/c4an01439a
PMCID:
PMC4280799
Author(s):
Uba, Franklin I.; Pullagurla, Swathi R.; Sirasunthorn, Nichanun; Wu, Jiahao; Park, Sunggook; Chantiwas, Rattikan; Cho, Yoon-Kyoung; Shin, Heungjoo; Soper, Steven A.
Publisher(s):
Royal Society of Chemistry (RSC); ROYAL SOC CHEMISTRY; The Royal Society of Chemistry
Tags:
Chemistry; Biochemistry, Genetics and Molecular Biology; Environmental Science; POLYMER MICROFABRICATION TECHNOLOGIES; DOUBLE-STRANDED DNA; NANOFLUIDIC CHANNELS; POLY(METHYL METHACRYLATE); CONCENTRATION POLARIZATION; ELASTOMERIC NANOCHANNELS; MICROANALYTICAL DEVICES; MICROFLUIDIC DEVICES; TRANSPORT PHENOMENA; WALL ROUGHNESS
article description
Thermoplastics have become attractive alternatives to glass/quartz for microfluidics, but the realization of thermoplastic nanofluidic devices has been slow in spite of the rather simple fabrication techniques that can be used to produce these devices. This slow transition has in part been attributed to insufficient understanding of surface charge effects on the transport properties of single molecules through thermoplastic nanochannels. We report the surface modification of thermoplastic nanochannels and an assessment of the associated surface charge density, zeta potential and electroosmotic flow (EOF). Mixed-scale fluidic networks were fabricated in poly(methylmethacrylate), PMMA. Oxygen plasma was used to generate surface-confined carboxylic acids with devices assembled using low temperature fusion bonding. Amination of the carboxylated surfaces using ethylenediamine (EDA) was accomplished via EDC coupling. XPS and ATR-FTIR revealed the presence of carboxyl and amine groups on the appropriately prepared surfaces. A modified conductance equation for nanochannels was developed to determine their surface conductance and was found to be in good agreement with our experimental results. The measured surface charge density and zeta potential of these devices were lower than glass nanofluidic devices and dependent on the surface modification adopted, as well as the size of the channel. This property, coupled to an apparent increase in fluid viscosity due to nanoconfinement, contributed to the suppression of the EOF in PMMA nanofluidic devices by an order of magnitude compared to the micro-scale devices. Carboxylated PMMA nanochannels were efficient for the transport and elongation of λ-DNA while these same DNA molecules were unable to translocate through aminated nanochannels.