Optimization of Nanofluidic Devices for Geometry‐Induced Electrostatic Trapping (Part. Part. Syst. Charact. 2/2021)

AbstractOur work focuses on the development of simpler and effective production of nanofluidic devices for high-throughput charged single nanoparticle trapping in an aqueous environment. Single nanoparticle confinement using electrostatic trapping has been an effective approach to study the fundamental properties of charged molecules under a controlled aqueous environment. Conventionally, geometry-induced electrostatic trapping devices are fabricated using SiOx-based substrates and comprise nanochannels imbedded with nanoindentations such as nanopockets, nanoslits and nanogrids. These geometry-induced electrostatic trapping devices can only trap negatively charged particles, and therefore, to trap positively charged particles, modification of the device surface is required. However, the surface modification process of a nanofluidic device is cumbersome and time consuming. Therefore, here, we present a novel approach for the development of surface-modified geometry-induced electrostatic trapping devices that reduces the surface modification time from nearly 5 days to just a few hours. We utilized polydimethylsiloxane for the development of a surface-modified geometry-induced electrostatic trapping device. To demonstrate the device efficiency and success of the surface modification procedure, a comparison study between a PDMS-based geometry-induced electrostatic trapping device and the surface-modified polydimethylsiloxane-based device was performed. The device surface was modified with two layers of polyelectrolytes (1: poly(ethyleneimine) and 2: poly(styrenesulfonate)), which led to an overall negatively charged surface. Our experiments revealed the presence of a homogeneous surface charge density inside the fluidic devices and equivalent trapping strengths for the surface-modified and native polydimethylsiloxane-based geometry-induced electrostatic trapping devices. This work paves the way towards broader use of geometry-induced electrostatic trapping devices in the fields of biosensing, disease diagnosis, molecular analysis, fluid quality control and pathogen detection.

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Optimization of Nanofluidic Devices for Geometry‐Induced Electrostatic Trapping

Particle & Particle Systems Characterization ◽

10.1002/ppsc.202000275 ◽

2021 ◽

Vol 38 (2) ◽

pp. 2000275

Author(s):

Deepika Sharma ◽

Roderick Y. H. Lim ◽

Thomas Pfohl ◽

Yasin Ekinci

Keyword(s):

Nanofluidic Devices ◽

Electrostatic Trapping

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A NOVEL TECHNIQUE FOR FABRICATION OF NANOFLUIDIC DEVICES WITH POLYMER FILM FORMED BY PLASMA POLYMERIZATION

High Temperature Material Processes (An International Quarterly of High-Technology Plasma Processes) ◽

10.1615/hightempmatproc.2015015712 ◽

2015 ◽

Vol 19 (1) ◽

pp. 1-18 ◽

Cited By ~ 4

Author(s):

Liubov I. Kravets ◽

Alla B. Gilman ◽

Mikhail Yu. Yablokov ◽

Veronica Satulu ◽

Bogdana Mitu ◽

...

Keyword(s):

Polymer Film ◽

Plasma Polymerization ◽

Novel Technique ◽

Nanofluidic Devices

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Fabrication of Ultranarrow Nanochannels with Ultrasmall Nanocomponents in Glass Substrates

Micromachines ◽

10.3390/mi12070775 ◽

2021 ◽

Vol 12 (7) ◽

pp. 775

Author(s):

Hiroki Kamai ◽

Yan Xu

Keyword(s):

Electron Beam ◽

Electron Beam Lithography ◽

Dry Etching ◽

Dissimilar Material ◽

Glass Substrates ◽

Nanofluidic Devices ◽

Fundamental Research ◽

Fine Glass ◽

Physical Phenomena

Nanofluidics is supposed to take advantage of a variety of new physical phenomena and unusual effects at nanoscales typically below 100 nm. However, the current chip-based nanofluidic applications are mostly based on the use of nanochannels with linewidths above 100 nm, due to the restricted ability of the efficient fabrication of nanochannels with narrow linewidths in glass substrates. In this study, we established the fabrication of nanofluidic structures in glass substrates with narrow linewidths of several tens of nanometers by optimizing a nanofabrication process composed of electron-beam lithography and plasma dry etching. Using the optimized process, we achieved the efficient fabrication of fine glass nanochannels with sub-40 nm linewidths, uniform lateral features, and smooth morphologies, in an accurate and precise way. Furthermore, the use of the process allowed the integration of similar or dissimilar material-based ultrasmall nanocomponents in the ultranarrow nanochannels, including arrays of pockets with volumes as less as 42 zeptoliters (zL, 10−21 L) and well-defined gold nanogaps as narrow as 19 nm. We believe that the established nanofabrication process will be very useful for expanding fundamental research and in further improving the applications of nanofluidic devices.

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Thermoplastic Nanofluidic Devices for Identifying Abasic Sites in Single DNA Molecules

Lab on a Chip ◽

10.1039/d0lc01038c ◽

2021 ◽

Author(s):

Steven A Soper ◽

Swarnagowri Vaidyanathan ◽

Franklin Uba ◽

Bo Hu ◽

David Kaufman ◽

...

Keyword(s):

Dna Damage ◽

Therapeutic Efficacy ◽

Double Strand Breaks ◽

Dna Molecules ◽

Strand Breaks ◽

Single Dna Molecules ◽

Abasic Sites ◽

Nanofluidic Devices ◽

Ap Sites

DNA damage can take many forms such as double-strand breaks and/or the formation of abasic (apurinic/apyrimidinic; AP) sites. The presence of AP sites can be used to determine therapeutic efficacy...

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Transport and Sensing in Nanofluidic Devices

Annual Review of Analytical Chemistry ◽

10.1146/annurev-anchem-061010-113938 ◽

2011 ◽

Vol 4 (1) ◽

pp. 321-341 ◽

Cited By ~ 33

Author(s):

Kaimeng Zhou ◽

John M. Perry ◽

Stephen C. Jacobson

Keyword(s):

Nanofluidic Devices

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Transport of Ions and Molecules in Nanofluidic Devices

ASME 2008 6th International Conference on Nanochannels, Microchannels, and Minichannels ◽

10.1115/icnmm2008-62065 ◽

2008 ◽

Author(s):

Rohit Karnik ◽

Chuanhua Duan ◽

Kenneth Castelino ◽

Rong Fan ◽

Peidong Yang ◽

...

Keyword(s):

Surface Charge ◽

Surface Area ◽

Field Effect ◽

Electrostatic Interactions ◽

Surface Reactions ◽

Molecular Transport ◽

Large Surface Area ◽

Ionic Concentrations ◽

Nanofluidic Devices ◽

Transport Of Ions

Interesting transport phenomena arise when fluids are confined to nanoscale dimensions in the range of 1–100 nm. We examine three distinct effects that influence ionic and molecular transport as the size of fluidic channels is decreased to the nanoscale. First, the length scale of electrostatic interactions in aqueous solutions becomes comparable to nanochannel size and the number of surface charges becomes comparable to the number of ions in the channel. Second, the size of the channel becomes comparable to the size of biomolecules such as proteins and DNA. Third, large surface area-to-volume ratios result in rapid rates of surface reactions and can dramatically affect transport of molecules through the channel. These phenomena enable us to control transport of ions and molecules in unique ways that are not possible in larger channels. Electrostatic interactions enable local control of ionic concentrations and transport inside nanochannels through field effect in a nanofluidic transistor, which is analogous to the metal-oxide-semiconductor field effect transistor. Furthermore, by controlling surface charge in nanochannels, it is possible to create a nanofluidic diode that rectifies ionic transport through the channel. Biological binding events result in partial blockage of the channel, and can thus be sensed by a decrease in nanochannel conductance. At low ionic concentrations, the effect of biomolecular charge is dominant and it can lead to an increase in conductance. Surface reactions can also be used to control transport of molecules though the channel due to the large surface area-to-volume ratios. Rapid surface reactions enable a new technique of diffusion-limited patterning (DLP), which is useful for patterning of biomolecules and surface charge in nanochannels. These examples illustrate how electrostatic interactions, biomolecular size, and surface reactions can be used for controlling ionic and molecular transport through nanochannels. These phenomena may be useful for operations such as analyte focusing, pH and ionic concentration control, and biosensing in micro- and nanofluidic devices.

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