Harnessing Microfluidics for Research and Development Nathaniel C. Cady Asst. Prof. Nanobioscience

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

2. Outline • Fluid dynamics (for non-majors) • Building microfluidic devices • Examples of research devices

3. Turbulent Flow

4. Laminar Flow

5. v d Flow regime is predictable! Reynolds Number Re = (density) x (velocity) x (diameter) (viscosity) If Re = 3000 or higher = turbulent flow If 2000-3000 = transitional flow If less than 2000 = laminar flow 2300 = transition point Microfluidic devices capitalize on small channel sizes to control flow regime

6. 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”

7. Device Fabrication

8. 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

9. Photolithography Transfer Pattern Develop Resist Etch substrate Remove Resist

10. Making a Microfluidic Device Direct Indirect

11. Fabrication is relatively easy…

12. Practical Applications Diagnostics

13. Microchip-based DNA Biosensor 35mm 20 mm Integrated DNA Purification & Real-Time PCR

14. DNA-based Diagnostics EtOH (wash buffer) GuSCN (lysis buffer) dH2O (elution buffer)

15. Micropillars for DNA Purification 10 microns

16. Integrated Control System

17. Detection Results Cady et. al. (2005) Sensors & Actuators B. 107(1): 332-341 Cady et. al. (2003) Biosensors & Bioelectronics. 19: 59-66

18. Practical Applications Micro Printing & Patterning

19. Biomolecular Printing 30 microns

20. PEG Hydrogel Probing Neural Networks Signaling ? SiO2 Gold Glass With Dr. Bill Shain & Dr. Matt Hynd – Wadsworth Center, NYS Dept. of Health

21. Biomolecular Printing Insert movie

22. 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) Hydrogel-coated MEA patterned with the laminin peptide, biotin-IKVAV. The laminin peptide biotin-IKVAV 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. Courtesy of: Matthew Hynd, PhD – NYS DOH

23. 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. Scanning electron microscope image of patterned neural network. Courtesy of: Matthew Hynd, PhD – NYS DOH

24. Cellular Printing Slow, difficult High acceleration / thermal exposure – potentially damaging to cells

25. 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 Printing Tip BioForce Silicon-based SPT Polymeric SPT

26. 100um E. coli pET28A-GFP TSA Plate (12 hr) Bacterial Cell Printing E. coli pET28A-GFP on polystyrene 20 μm 20 μm 20 μm

27. Mammalian Cell Printing Mouse MTLn3-GFP (diluted) printed on polystyrene 50 μm

28. Practical Applications Cell Dynamics

29. Biomimetic Device for Tumor Cell Dissemination Studies Weir Structures (Constrictions) Collection Area O2 Input Output Tumor Cell Input 1000µm Cell Weir Structures (Constrictions)

30. Flow Cell Design Device Filled with Dye 500µm Fluid Flow Direction

31. Fluid Dynamic Modeling Fluid velocity vectors Units: (cm/sec) 500µm

32. Device Testing HEp3 Cells (Human Epidermal Carcinoma 3) Fluid Flow Cells were smaller than anticipated – needed different weir spacing! 100um

33. Rapid Prototyping of New Device Fluid Flow 100um

34. 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

35. Acknowledgements University at AlbanyMt. 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