1. “Flow Characterization in a Microfluidic Compact Disc (CD) Platform for Clinical Diagnosis”
SURF-IT Fellow: Bryce Kubo
Mentor: Professor Marc Madou
Kameel Abi-Samra

2. What is microfluidics?
Comparison to a regular sewage pipe to microchannel
Differences in flow (capillary action)
About what size is a micro channel
Fig. 5 from M. Madou, et al, “Lab on a CD,” Annual Rev of Biomed Eng, vol. 8, pp , 2006.

3. What I am testing Materials: Plastic vs. Silicon
Speed of Rotation: Slow vs. Fast
Width of the Channels: Wide vs. Narrow
Distance from Center: Close vs. Far
Materials: Effect on flow rate
Speed: Does every liquid have the same flow rates at specific RPMs
Currently working:
Width: Flow 350 RPM & Burst Frequency
Distance: Burst Frequency

4. Burst Frequency ρωc2ṝ∆r = a(4γ/Dh) + b
The angular frequency in which the liquid will break through the capillary valve and begin flowing
M. Madou, et al, “Lab on a CD,” Annual Rev of Biomed Eng, vol. 8, pp , 2006.
From Dr. Madou’s Lab on a CD, discovered by him and fellow writers of the paper
Critical to whole project:
Effects flow rate and liquids

5. How can a simple plastic CD be used for biomedical testing?
Mixing Liquids
Valving
Metering
Mixing liquids: two channels meet, splash together in chamber
Valving: prevention of fluids flowing from channel to chamber or vice versa

6. Valving
2 Types: Hydrophobic Valves & Capillary Valves
Hydrophobic: Narrowing of channel, hydrophobic materials within channel, designed channel design
Capillary: Just using surface tension
Schematic illustrations for the description of CD microfluidics. (a) Two reservoirs connected
by a microfluidic chamber. (b) Hydrophobic valve made by a constriction in a chamber made of
hydrophobic material. (c) Hydrophobic valve made by the application of hydrophobic material
to a zone in the channel. (d) Hydrophobic channel made by the application of hydrophobic
material to a zone in a channel made with structured vertical walls (see inset). (e) Capillary valve
made by a sudden expansion in channel diameter, such as when a channel meets a reservoir.
Fig. 2 from M. Madou, et al, “Lab on a CD,” Annual Rev of Biomed Eng, vol. 8, pp , 2006.

7. Metering
Technique used when trying to separate materials/fluids by spinning in certain directions and speeds
Schematic illustration of the microfluidic structure employed for the ion selective optode CD
platform. The fluidic structure contains five solution reservoirs, a detection chamber, and a
waste reservoir. The reservoirs contain the first and second calibrant, wash solutions, and the
sample. Upon increasing rotation rates, calibrant 1, wash 1, calibrant 2, rinse 2, and then
sample were serially gated into the optical detection chamber. Absorption of the calibrants and
sample was measured.
Fig. 4 from M. Madou, et al, “Lab on a CD,” Annual Rev of Biomed Eng, vol. 8, pp , 2006.

8. SpinDEP
Fig. 1. A) A mounted SpinDEP platform. A polycarbonate CDlike
platform holds up to 2 CarbonDEP chips. Platform size is
the same as a traditional music CD. AC signals are interfaced to
this spinning platform through rotary metal rings and stationary
contact pads. B) A CarbonDEP chip contained in the spinning
platform. Signal is brought to the chip by simple wiring. C) Size
comparison of a CarbonDEP chip against a U.S. dime. Loading
and retrieval chambers and channel containing the electrodes
are fabricated on polycarbonate and adhered to the silicon
substrate through pressure sensitive double-sided adhesive.
Fig. 1 from R. Martinez-Duarte, et al, “The Integration of 3D Carbon Dielectrophoresis on a Rotating Platform”

9. Any Questions?
Thank you to the SURF-IT program along with Dr. Ross, Dr. Lee, Dr. Shokair, and my Mentor Dr. Madou and his research group