| Description |
Microfluidics is an emerging field that deals with the technology and science of manipulation of fluid in microchannels. Since its birth in the 1990s, it has now gradually matured into an enabling technology, like microelectronics and software engineering. A majority of current applications of microfluidics are in life sciences. Polydimethylsiloxane (PDMS) is a soft elastomer and a popular material for fabricating microfluidic devices. This is due to PDMS's unique set of material properties and low cost. Furthermore, the unique mechanical properties of thin PDMS layers/membranes (< 200 µm) can be used to increase the functionality of PDMS-based microfluidic systems. In this presentation, three unique neuroscience applications of PDMS-based microfluidic devices are presented. The working principle behind each of these devices depends on the unique properties of thin PDMS layers. In the first project a fabrication protocol was developed to stack 30 patterned 10-um thick PDMS layers on top of each other without any trapped air bubbles or wrinkles. Each PDMS layer was patterned by spin-coating uncured PDMS on a photolithographic micromold at very high spin speeds and thermally curing the layer later. The layer stacking procedure was done manually using no specialized tools and did not cause any layer deformation to inhibit functionality. This fabrication protocol was used to develop the first ever microfluidic Magnetic Resonance Imaging Phantom to stimulate brain white matter. In the second project, laser ablation was used to rapidly prototype micromolds and by using these micromolds a unique fabrication protocol was developed and characterized to build microvalve arrays (consisting of 100s of microvalves) without access to any cleanroom facility. This was achieved by manipulating the stiffness of thin PDMS layers that are inherent part of pneumatic microvalves. These microvalve arrays were used to build a microfluidic platform for manipulation of C. elegans (a type of a small round worm), which are used extensively for neuronal behavioral analysis. In the last project using similar fabrication techniques (as described in the second project) microfluidic genotyping devices are developed for zebrafish embryos that are less than 2 days old. The unique advantage of the microfluidic zebrafish genotyping devices is that they enable researchers to collect genetic material (for genotyping) from a zebrafish embryo (1 to 2 days old) without causing any harm to its health. This capability is not possible with any other model multicellular organism to date. The working principle behind one of the presented genotyping devices depends on the controlled actuation of PDMS membranes. |
