Microfluidic very large scale integration (mVLSI) with integrated micromechanical valves

Abstract

Microfluidic chips with a high density of control elements are required to improve device performance parameters, such as throughput, sensitivity and dynamic range. In order to realize robust and accessible high-density microfluidic chips, we have fabricated a monolithic PDMS valve architecture with three layers, replacing the commonly used two-layer design. The design is realized through multi-layer soft lithography techniques, making it low cost and easy to fabricate. By carefully determining the process conditions of PDMS, we have demonstrated that 8 × 8 and 6 × 6 μm(2) valve sizes can be operated at around 180 and 280 kPa differential pressure, respectively. We have shown that these valves can be fabricated at densities approaching 1 million valves per cm(2), substantially exceeding the current state of the art of microfluidic large-scale integration (mLSI) (thousands of valves per cm(2)). Because the density increase is greater than two orders of magnitude, we describe this technology as microfluidic very large scale integration (mVLSI), analogous to its electronic counterpart. We have captured and tracked fluorescent beads, and changed the electrical resistance of a fluidic channel by using these miniaturized valves in two different experiments, demonstrating that the valves are leakproof. We have also demonstrated that these valves can be addressed through multiplexing.

Flow-Layer Physical Design for Microchips Based on Monolithic Membrane Valves

“…The most widely recognized microvalve technologies are elastomeric valves based on multilayer soft lithography, developed at Stanford University [1], and monolithic membrane valves developed at the University of California Berkeley [4]. Although the software platform that we are developing is technology independent, we target the University of California Berkeley monolithic membrane valves, shown in Figure 1.…”

Recent developments in microfluidic large scale integration

“…The Quake research group at Stanford University has recently demonstrated integration of 1 million control elements onto a single chip is possible through microfluidic very large scale integration (mVLSI) [33 ]. mVLSI has the potential to realize high dynamic range and reconfigurable chips for digital-PCR, digital-MDA or digital-ELISA applications.…”

Microfluidic actuators based on temperature-responsive hydrogels

“…Pressure actuated polydimethylsiloxane (PDMS) microvalves 3 deserve particular attention because, owing to their simplicity, thousands of units can be integrated on a single device, linking microfluidics and microelectronics 4 . PDMS valves currently represent an important tool for biology research [5][6][7][8] . In addition, dropletbased technology offers new methods of fluid manipulation, which are particularly powerful when high throughput is required [9][10][11] .…”