BIOEN 455 (BioMEMS, Folch) Section 4: Microelectrochemical sensing of cell behavior

5. Cell-based chips A. Microfluidic flow cytometers

Cell sorting

Cell trapping

Microfluidic cell culture laboratories

Gene expression cellular microarrays (“Cellomics”)

Micro-Bioreactors

Cells on microelectrodes

Patch-clamp chips

Cryopreservation

Assisted reproduction technologies

Whole-animal testing

5-1. Hydrodynamic focusing using electrokinetic flows

5-2. Microfluidic flow cytometer integrated in SU-8

5-3. Three-dimensional hydrodynamic focusing using two-layer PDMS microfluidics

5-4. Single-layer 3D flow focusing

5-5. Three-dimensional hydrodynamic focusing using Chevron grooves

5-6. Single-layer microfluidic device producing 3D focused flow

5-7. Contraction-expansion array resulting in 3D focused flow

5-8. Extreme-throughput, sheathless flow cytometry

5-9. A microfluidic device to study erythrocyte deformability

5-10. Modeling malaria infection in microchannels

5-11. First on-chip biochemical manipulation of cells

5-12. Particle separation using spiral microchannels

5-13. Pinched-flow fractionation of beads

5-14. Tuneable hydrophoretic focusing

5-15. “Neuro-cages” for extracellular recording from in-vitro neural networks

5-16. Cell trapping in PDMS microwells

5-17. Microwells addressed with microfluidics

5-18. Cell trapping with PEG microwells

5-19. Dielectrophoretic trapping of cells

5-20. Dielectrophoretic trapping and sorting of cells

5-21. A CMOS-microfluidic hybrid for cell manipulation

5-22. Hydrodynamic traps for high-speed single-cell analysis

5-23. Arrays of hydrodynamic cell traps

5-24. Microfluidic control of cell pairing and fusion

5-25. Cell traps for studying cell-cell contacts

5-26. A high-efficiency hydrodynamic trapping device

5-27. Microfluidic immunocapture of rare cancer cells

5-28. Micromolded rafts for cell culture

5-29. Microcontainers loaded with biological contents

5-30. Bacterial cell cultures and assays in microdroplets

5-31. High cellular viability in microdroplets

5-32. Limitations of traditional cell culture technology

5-33. Seeding cells in microchannels

Challenge: To uncover the functions of genes and to identify gene products

Transfection with cDNAs of gene of interest containing a construct for a fluorescent protein (e.g. GFP, etc.)

Approach: Transfected cell microarrays

cDNAs printed on glass slide with a robotic arrayer

HEK293T cells seeded on the cDNA micropattern

Cells take up the cDNA and co-express gene of interest and GFP

100 m

30-80 cells

co-expression

5-34. Gene-expression cell array

5-35. Microfluidic gene-expression cell array

5-36. Increased throughput and physiological relevance of microfluidic systems

5-37. A microfluidic mechostat to maintain constant cell culture conditions

5-38. Microfluidic cell culture analog

5-39. Transparent MEAs fabricated in indium tin oxide (ITO)

5-40. MEAs combined with microtunnels to measure axonal signal conduction velocity

5-41. Field-effect transistors to record the electrical activity of cells

5-42. Nanowire field-effect transistor arrays for recording from brain slices

5-43. “In-cell” recording and stimulation by extracellular microelectrodes

5-44. Patch clamp technique

5-45. Conceptual comparison between the (a) traditional approach and (b) the planar chip-approach to patch-clamp recording

5-46. Patch-clamp chips micromolded in PDMS

5-47. Silicon oxide micro-nozzles for patch-clamp recordings

5-48. A glass patch-clamp chip capable of detecting single-ion channel activity

5-49. A PDMS patch-clamp chip with a lateral aperture

5-50. A PDMS lateral patch-clamp chip design that delivers high-yield giga-seals

BIOEN 455 (BioMEMS, Folch) Section 4: Microelectrochemical sensing of cell behavior

Switching of extracellular solutions

15 frames/sec

Total 40 sec in real time

20 m

BIOEN 455 (BioMEMS, Folch) Section 4: Microelectrochemical sensing of cell behavior

50 m

Microfluidic Modulation

Intracellular Modulation (intracellular messengers)

Extracellular Perfusion (drug screening)

perfusion

channels

BIOEN 455 (BioMEMS, Folch) Section 4: Microelectrochemical sensing of cell behavior

Extracellular Modulation [K+]o

Vr

[K+]

Success rates

Oxygen plasma treatment of PDMS: 100 W, 700 mTorr, 6 min

GW seal rate: 52 % on Rat Basophilic Leukemia cells

0

100

Pe

rce

nta

ge

(%

)

Immobilization

of cells

Formation

of GW seal

Whole-cell

recordings

(n = 74)

(42)

(22)

(15)

20 m

RBL cell

57

30

20

52%

68%

5-51. Microfabricated glass capillaries for patch clamp on a chip

5-52. A microfluidic device for measuring osmotic properties

5-53. Evaluation of sperm motility using microfluidic channels

5-54. Sperm sorting based on sperm motility in a laminar flow

5-55. A biomimetic device for in-vitro fertilization

5-56. High-throughput screening of C. Elegans with a microfluidic chip