Research Teams Update: Platforms and Testbeds

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Research Teams UpdatePlatforms and Testbeds

• CONGS The Council of Nanoscience Graduate
  Students
• The Ohio State University
• NSEC CANPBD

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Research Team Leaders

• Testbeds
• Nanofactory Jingjiao Guan
• Magnetics Burr Zimmerman
• Platforms
• Nanofibers Sarah Drilling
• Supercritical Fluids Yong Yang
• Nanofluidics Pradeep Gnanaprakasam
• Nanomfg Hae woon Choi

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Nanofactory Testbed

• Led by Jingjiao Guan

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Nanofactory--- Hydrodynamic conjugation
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PEI
PEI
DNA
DNA/PEI
PEI
PEI
250 um
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Magnetic Separations Testbed

• Led by Burr Zimmerman

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Magnetics Testbed

• Rare protein isolation and enrichment
• Combining nanofabrication with magnetic
  separations
• Nanofabrication
• Nanofluidics
• Nanoparticles
• Modeling

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Why Nano?

• Examining the magnetic force,
• Reducing the distance between magnetic pole
  pieces increases ?B proportionally
• Current separation 1mm
• 10-100nm separation increases force by 4-5 orders
  of magnitude

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Pretty Pictures
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Potential Publications

• Microchannel fabrication and subsurface
  machining with femtosecond laser
• Choi, Zimmerman, Farson, J. Lee and Chalmers
• Synthesis of labeled magnetic nanoparticles
• Pan, Shenkman, Wu, Nielson, Rampersaud, B. Lee,
  Wyslouzil, Rathman, Good, Chalmers
• Combining magnetic separations with
  electrokinetic flow
• Zimmerman, Shenkman, Zborowski, Olesik, Chalmers,
  J. Lee
• Modeling nanoscale particle sorting
• Yu, Zimmerman, Fan, Chalmers, J. Lee)

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Nanofibers PlatformRecent Results

• Used electrospun PCL fibers to create
  nanochannels in PDMS
• Laser cut channels in electrospun material to
  create engineered channels to direct cell growth

• Created and tested terpolymer bilayers for
  vascular replacements
• Acquired initial data needed to develop a model
  for the mechanical properties of tissue
  engineering scaffolds

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Thickness of Coating
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Cross Section of PDMS
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Nanofibers PlatformContinuing Goals

• Measuring flow through nanochannels
• Sample sent to Georgia Tech
• Use laser cut cavities to allow chemical cross
  talk between cells while retaining physical
  separation
• Fabricate electrospun scaffolds for use by NSEC
  collaborators
• Examine cellular viability following dynamic cell
  seeding

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Super/Subcritical Fluids Technology

• Advantages of CO2
• General
• Environmentally benign
• Nontoxic
• Nonflammable
• Low cost
• Polymers
• High solubility
• Tg depression
• Reduced viscosity
• Reduced interfacial tension

CO2 conditions in this study
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SCF Core Technology Research

• Explore the fundamental interactions between
  polymers and SCFs
• Solubility
• Swelling
• Glass transition temperature
• Rheology
• Develop techniques to fabricate and modify
  polymeric micro/nanodevices
• Surface modification
• Low-temperature bonding
• Tissue engineering
• Foaming

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SCF Core Technology in Our Nanofactory

• Practical Phase to Move Reagents
• High speed flow through channels
• CO2 enhanced polymer bonding
• Impregnate drug into implants
• Functionalization of well-defined 3D
  nanostructures

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Low T/P CO2 Bonding at the Micro/Nanoscale
PS lid
bonded interface
PS nanochannels
PLGA
200 nm
_at_ 70oC, 200psi
_at_ 35oC, 100psi
Microfabricated Tissue Engineering Scaffolds
100 mm
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Nanofluidics Platform

• Continuum Modeling
• Lubrication and DH Approximation (Gnanaprakasam)
• Numerical Model (Gnanaprakasam)
• Mass conservation of deformable objects like
  droplets, bubbles in a flow channel (Yu)
• Molecular Dynamics Modeling
• Model for amorphous Silica
• Electrophoresis of Poly balls in uncharged
  nanochannels
• Brownian Dynamics Simulation
• Effect of electrokinetic interactions on the
  movement and flow patterns of charged particles
  in micro/nanofluidics (Yi-Je Juang, Xin Hu,
  Shengnian Wang, etc.).
• Fractal design of a universal micro/nanofluidics
  network for the manipulations of the charged
  particles or long-chain molecules (Xin Hu,
  Shengnian Wang, etc.).
• Bead-rod chain modeling for DNA molecules (Xin
  Hu).

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Poiseuille flow near rough hydrophobic surfaces
(Singer etal)
Water
Sinusoidal hydrophobic wall
Water

• Repulsion near valleys
• Slip at Boundary

Electrophoresis of Poly balls in nanochannels
with neutral walls
polyballs and counterions has a very interesting
character short periods of rapid motion are
interspersed among relatively long periods of
almost no motion.
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Multiphase modeling (Fan etal)

• Current work
• Bubble motion in structured micro channels

• Near term plan - Free surface flow in
  microchannels

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Brownian Dynamics simulation of DNA (Lee etal)
Brownian Dynamics Simulation (DNS) is a
coarse-grained simulation method, which is used
to study the movements of rigid particles and
flexible long-chain polymers. Currently, the
bead-spring and bead-rod chain models are widely
used to simulate the DNA molecules. We use the
finite element method (FEM) to solve the
electrokinetic/hydrodynamics flows first, then
run the Brownian dynamics simulation to study the
movement and conformation change of DNA molecules
in the micro/nanofluidics. Finally, the results
are compared with the experiments.
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Future Plans

• Continuum Modeling
• Numerical model for 2D electroosmotic flow in
  nozzles. (Gnanaprakasam)
• Develop boundary condition for wall deposition
  process.(Gnanaprakasam)
• Develop model for surface channel in
  microfluidics. (Yu)
• MD Simulations
• Interaction of biomolecules with amorphous
  Silica walls (Singer)
• Poly balls in channels with charged walls and
  nozzle geometry. (Singer)
• Brownian Dynamics Simulation
• DNA movements in moving free surface (Xin Hu,
  Zhao Yu, Guojun Xu).
• DNA movement in converging/diverging channels
  driven by electrokinetic forces (Xin Hu,
  Shengnian Wang).

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Potential Publications

• Modeling Transport in Converging/Diverging
  Micro/Nano Nozzles, (P.Gnanaprakasam, A. T.
  Conlisk, X. Hu, L. J. Lee)
• Modeling the Dynamic self assembly of a
  Nanonozzle, (P.Gnanaprakasam, A. T. Conlisk, J.
  Shearer, S. Olesik)
• Continuum and atomistic approaches to
  electrokinetic flows in nanochannels, (Hui Zhang,
  Lei Chen, Terry Conlisk and Sherwin J. Singer)

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Nanomanufacturing Platform
Background

• Conventional lithography is effective for
  materials with less desirable properties and
  requires expensive clean room processes.
• Polymers have attractive properties, but
  nanoscale features are difficult to produce.

Objectives

• Demonstrate a non-cleanroom nano-manufacturing
  process
• Develop fabrication technology for hard metal
  molds for a more durable and economic way to
  fabricate nanochannels.

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Nanomanufacturing Platform
Hot embossed channel (5mm)
Microfluid channel on PMMAN
SU-8 Mold
Nanoscale (85nm) channel


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Discussion and Questions?