Research

MEMS Design

  • Microneedles
  • Valves
  • Pumps
  • Polymers

BioMEMS Applications

  • Vaccine delivery
  • Drug Delivery
  • Diabetes management
  • Biosensors

Fluid Mechanics

  • Computational modeling
  • Fundamental flow phenomena
  • Two-phase flows
    - capillary flows
    - with particles
    - with large biomolecules
  • Non-Newtonian fluid mechanics

Integrated Systems

  • Micro-Syringe
  • Continuous Micro-Mixer
  • Glucose Sensor
  • Micro-Capillary Pumped Loop Cooler

 

 

 

Integrated MEMS Systems

Micro-Syringe

Micro-Syringes have been developed for the delivery of lyopholized or dried drugs. The drug is delivered in a non-aqueous solution just under the skin where it is dissolved by the interstitial fluid and absorbed by the capillary blood vessels. All this is above the nerve endings so it does not hurt.

The overall goal of this project is to be able to effectively distribute vaccines in remote areas that do not have sufficient medical care. On the right is a picture of a microsyringe made by Boris Stoeber. We have demonstrated that the microneedles do actually deliver drugs effectively.

Micro-Mixer

Continuous micro-mixer was our first integrated fluid system. This device requires only power and a fluid source. Pumping, valving and mixing are all performed by on-chip MEMS components. The system has been encased into a custom designed injection molded case. The work was performed by Ajay Deshmuhk (PhD, M.E., 2002).

The system contains two positive displacement pumps (each with 2 check valves). The pumps provide alternating flow in the center channel forming an interface that gets stretched as the flow evolves downstream. The rapid increase in interfacial area accelerates mixing as shown in the lower picture. The fundamental theory behind this approach is that three degrees of freedom are required for complex flow patterns (see Aref and Jones papers). MEMS devices are generally planar so in this device the third degree of freedom is provided by time-dependent flow.

Glucose Sensor

The laboratory is currently working on a continuous glucose sensor that uses the micro-needles described above with an integrated flow-through enzymatic (glucose oxidase) assay. This work, done by Stefan Zimmerman, Boris Stoeber, and Dorte Fienbork, uses a new approach for "in device" enzyme patterning that can be done after wafer level fabrication. The device has four hundred microneedles for the acquisition of interstitial fluid.

Micro-Capillary Pumped Loop for Chip Cooling

Many integrated circuits today are limited by heat transfer. The schematic above right shows the third generaion of a micro-CPL cooler which uses phase change to provide advanced thermal management for multichip modules. The system shown below right is the device cooling a power transitor. The system has been demonstrated to remove over 300 Watts per sq. cm. This work was done by Jeff Kirshberg (PhD 2002) and KIP Pettigrew (MS 2003).