Transcript Harnessing Microfluidics for Research and Development Nathaniel C. Cady Asst. Prof. Nanobioscience College of Nanoscale Science & Engineering.

Harnessing Microfluidics for
Research and Development
Nathaniel C. Cady
Asst. Prof. Nanobioscience
College of Nanoscale Science & Engineering
Outline
• Fluid dynamics (for non-majors)
• Building microfluidic devices
• Examples of research devices
Turbulent Flow
Laminar Flow
Flow regime is predictable!
Reynolds Number
Re =
(density) x (velocity) x (diameter)
(viscosity)
v
If Re = 3000 or higher = turbulent flow
If 2000-3000 = transitional flow
d
If less than 2000 = laminar flow
Microfluidic devices
capitalize on small
2300 = transition point
channel sizes to control
flow regime
Advantages of Microfluidic Devices
• Well-controlled fluid dynamics
•Diffusion-limited mixing
•Controllable fluid interactions
• Small fluid volume
•Less sample and reagent needed
•More samples per unit area (multiplexing)
Microfluidics = “Lab-on-a-chip”
Device Fabrication
Fabrication of Microfluidic Devices
• Fabrication schemes range from simple to highly
complex
• Primarily rely on micro / nanofabrication
techniques
• Lithography (photo-, electron beam, imprint)
• Etching or molding of 3-D channels
• “Capping” or enclosure of channels
Photolithography
Transfer Pattern
Develop Resist
Etch substrate
Remove Resist
Making a Microfluidic Device
Direct
Indirect
Fabrication is relatively easy…
Practical Applications
Diagnostics
Microchip-based DNA Biosensor
35mm
20 mm
Integrated DNA Purification & Real-Time PCR
DNA-based Diagnostics
GuSCN (lysis buffer)
EtOH (wash buffer)
dH2O (elution buffer)
Micropillars for DNA Purification
10 microns
Integrated Control System
Detection Results
Category
Organism / Target
DNA Purification
Real-Time Detection
Detection Limit
Bacteria
Salmonella typhimurium
Yes
Yes
10 cells
Bacillus anthracis (Sterne)
Yes
Yes
40 cells
Listeria monocytogenes
Yes
Yes
100 cells
Staphylococcus aureus
Yes
Yes
--
Escherichia coli
Yes
Yes
--
Bacillus globigii (subtilis )
Yes
Yes
--
Phage
Lambda
Yes
Yes
--
Parasites
Leishmania donovani
Yes
Yes
--
Human
CYP3A56 (SNP)
Yes
Yes
--
ABCA1 (SNP)
Yes
Yes
--
Amelogenin (SNP, gender)
Yes
Yes
--
Cady et. al. (2005) Sensors & Actuators B. 107(1): 332-341
Cady et. al. (2003) Biosensors & Bioelectronics. 19: 59-66
Practical Applications
Micro Printing & Patterning
Biomolecular Printing
30 microns
Probing Neural Networks
Signaling ?
PEG Hydrogel
SiO2
Gold
Glass
With Dr. Bill Shain & Dr. Matt Hynd – Wadsworth Center, NYS Dept. of Health
Biomolecular Printing
Insert movie
Printed Guidance for Neural Networks
• Microelectrode arrays (MEAs) coated with PEG-based hydrogel
• NeN used to pattern hydrogel with FITC-labeled bioactive peptides
• Successful printing of both spots and lines
200um
Microelectrode Array
(MEA)
Courtesy of: Matthew Hynd, PhD – NYS DOH
Hydrogel-coated MEA patterned with the laminin
peptide, biotin-IKVAV. The laminin peptide biotinIKVAV was printed onto using the automated
NanoEnabler bioprinter. Printed peptide was arranged
in a pattern consisting of orthogonal 2 mm-wide lines
connecting 10 mm diameter node.
Neural Networks
• Printed MEAs seeded with primary hippocampal neurons
• Cells proliferated on the arrays and formed neural network on MEAs
• Results were comparable to studies using microcontact printing methods
(Hynd, et. al., J. Neuroscience Methods, 2006)
200um
Patterned neuronal network at 2 weeks in vitro. Primary
hippocampal neurons were plated onto patterned arrays
at a density of 400 cells/mm2.
Courtesy of: Matthew Hynd, PhD – NYS DOH
Scanning electron microscope image of
patterned neural network.
Cellular Printing
Slow, difficult
High acceleration / thermal exposure –
potentially damaging to cells
Direct Cell Printing
Polymeric Surface Patterning Tool
• Developed at CNSE, UAlbany (Cady
Lab)
• Designed to enable live cell printing
directly onto solid surfaces
• Larger channels and cantilever allow
for whole cells to be printed
Fluid
Reservoir
Channel
30 microns
Printing Tip
BioForce Silicon-based SPT
Polymeric SPT
Bacterial Cell Printing
E. coli pET28A-GFP on polystyrene
20 μm
20 μm
20 μm
E. coli pET28A-GFP TSA Plate (12 hr)
100um
100um
Mammalian Cell Printing
Mouse MTLn3-GFP (diluted) printed on polystyrene
50 μm
Practical Applications
Cell Dynamics
Biomimetic Device for Tumor Cell
Dissemination Studies
O2 Input
Weir Structures
(Constrictions)
Collection
Area
Output
Tumor Cell
Input
1000µm
Cell
Weir Structures
(Constrictions)
Flow Cell Design
Device Filled with Dye
500µm
Fluid Flow Direction
Fluid Dynamic Modeling
Fluid velocity vectors
Units:
(cm/sec)
500µm
Device Testing
HEp3 Cells
(Human Epidermal
Carcinoma 3)
Cells were smaller than
anticipated – needed
different weir spacing!
100um
Rapid Prototyping of New Device
100um
Summary
• Microfluidic devices reduce sample volume
and offer unique fluid dynamic
environments
• Novel fluid dynamics can affect reaction
rates, diffusion, biological processes
• Practical applications (like patterning) can
be accomplised using microfluidics
• Novel fluid environments can be used for
biomimetic studies
Acknowledgements
University at Albany
Mt. Sinai
Dr. Robert Geer
Dr. Julio Aguirre-Ghiso
Dr. Magnus Bergkvist
Dr. Alain Kaloyeros
Research Support
UAlbany Startup Funds
UAlbany FRAP A&B Awards
BioForce Instruments
CNSE / CAS Challenge Grant