PMMA/PDMS valves and pumps for disposable microfluidics

Abstract

Poly(methyl methacrylate) (PMMA) is gaining in popularity in microfluidic devices because of its low cost, excellent optical transparency, attractive mechanical/chemical properties, and simple fabrication procedures. It has been used to fabricate micromixers, PCR reactors, CE and many other microdevices. Here we present the design, fabrication, characterization and application of pneumatic microvalves and micropumps based on PMMA. Valves and pumps are fabricated by sandwiching a PDMS membrane between PMMA fluidic channel and manifold wafers. Valve closing or opening can be controlled by adjusting the pressure in a displacement chamber on the pneumatic layer via a computer regulated solenoid. The valve provides up to 15.4 microL s(-1) at 60 kPa fluid pressure and seals reliably against forward fluid pressure as high as 60 kPa. A PMMA diaphragm pump can be assembled by simply connecting three valves in series. By varying valve volume or opening time, pumping rates ranging from nL to microL per second can be accurately achieved. The PMMA based valves and pumps were further tested in a disposable automatic nucleic acid extraction microchip to extract DNA from human whole blood. The DNA extraction efficiency was about 25% and the 260 nm/280 nm UV absorption ratio for extracted DNA was 1.72. Because of its advantages of inexpensive, facile fabrication, robust and easy integration, the PMMA valve and pump will find their wide application for fluidic manipulation in portable and disposable microfluidic devices.

The MainSTREAM Component Platform: A Holistic Approach to Microfluidic System Design

“…Unlike many other valves that employ deflection of elastomeric membranes, 16,[40][41][42][43][44] the MainSTREAM valve is located outside and apart from the microfluidic chip it addresses (as is the peristaltic micropump). Compared with the use of screws, 44,45 the camshaft in our valve simplifies operation as it coordinates valving of multiple channels simultaneously.…”

Microtechnology for Mimicking In Vivo Tissue Environment

“…Combination with computer-controlled solenoid enabled fabrication of a micropump with a relatively wide range of pumping rates. 89 Mixing is another area of interest in microfluidics. The small size in microfluidics naturally results in a laminar flow with diffusion-dominating transport, which has been used extensively for precise control of the flow.…”

Automated, Miniaturized, and Integrated Quality Control-on-Chip (QC-on-a-Chip) for Cell-Based Cancer Therapy Applications

“…The fabrication method of choice is guided by multiple factors, including available infrastructure (technology and equipment), fabrication speed, cost (multi-use or disposable devices), desired feature size, as well as the preferred fabrication material. While initially glass-and silicon-based materials were used to fabricate microfluidic devices Manz et al, 1992), replica molding has become a dominate trend in recent years due to its fast and inexpensive fabrication of microdevices using polydimethylsiloxane (PDMS) (McDonald and Whitesides, 2002;Zhang et al, 2009Zhang et al, , 2010Berthier et al, 2012), hydrogels, thermoset composites (Carlborg et al, 2011;Sollier et al, 2011), and thermoplastics (Duffy et al, 1998;Fiorini et al, 2003Fiorini et al, , 2004Golden and Tien, 2007;Novak et al, 2013). The application of replica molding, also called "soft lithography" (Xia and Whitesides, 1998), eliminates the need for time-and cost-intensive clean room infrastructures.…”