Development of a Modular Peristaltic

Microfluidic Pump and Valve System

1/30/2007

BME 273 Group 20:

Adam Dyess, Jake Hughey, Michael Moustoukas, Matt Pfister

Microfluidics

• Minimal reagent consumption

• Increased speed of reactions

• Study of biological phenomena at the single cell level

Current Pumps at VIIBRE

• Harvard Pico Plus syringe pumps

• $2,000 / pump

• Limiting complexity of microfluidic devices

Diagram of the SystemNitrogen or Liquid

Fluid Flow

Pneumatic Valves

Peristaltic Pump

Christmas Tree Nanophysiometer

Pneumatic Valves

• Two-layer PDMS device– Flow layer– Control layer

• Thin PDMS membrane deflects into the flow channel when the control channel is pressurized

Unger et al. 2000

• 4 pneumatic valves in series

• Control pressure 20-25 psi• Flow channel dimensions

– 100 um wide, 10 um tall (round) or 5 um tall (rectangular)

• Control channel– Valve area (300 um by 300

um)

Current Design of Peristaltic Pump

Pump in Action

Completed Work

• Safety, photolithography, and microfabrication training

• Initial estimates of flow rates are 5 nl/min – much too low

• Fabricated and tested devices with flow above and control below – membrane stuck to roof of flow channel

Control

ControlFlow Flow

Current Status

• Will try changing “off” state of control line to vacuum

• Developing ways to increase flow rates – likely need at least 100 nl/min

• Multiphase parallel pumps are ready to be fabricated

• The fabrication of a second control box is about to begin

Current Work

• Increase cross-sectional area of flow channel• Vias to switch flow channel layer• Characterize flow rates

– Pulse-chase with bolus of fluorescent solution– Head to head vs. syringe pump

Kartalov et al. 2006

Flow

Groisman & Quake 2004

t = 0

t = d / v

LabVIEW Interface

• Design an improved interface that allows for input of pump sequences - possibly using Excel

• Controls will include valve on/off, rate, time, and schedule

Future Work

• Tesla valves or microfluidic rectifiers for anisotropic flow resistance

• Pumps at either end of device for push/pull

• Long-term testing of mechanical stability of pumps

• Sylgard 186 for mechanical properties instead of Sylgard 184 Bardell 2000

Groisman & Quake 2004