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Light-actuated high pressure-resisting microvalve for on-chip flow control based on thermo-responsive nanostructured
Guofang Chen1, Frantisek Svec, Daniel R Knapp
1Department of Pharmacology and MUSC Proteomics Center, Medical University of South Carolina, Charleston, SC 29425, USA. cheng@stjohns.edu
Lab on a Chip
|June 28, 2008
Summary
A novel light-actuated microvalve simplifies micro-total analysis systems. This thermo-responsive poly(N-isopropylacrylamide) valve offers high pressure tolerance and fast response times, ideal for microfluidic applications.
Area of Science:
- Microfluidics
- Materials Science
- Analytical Chemistry
Background:
- Micro-total analysis systems (µTAS) often require complex on-chip integration for flow control.
- Existing microvalves can be bulky, expensive, or difficult to integrate.
- Need for simple, effective flow manipulation in microfluidic devices.
Purpose of the Study:
- To introduce a simple light-actuated microvalve for effective flow path manipulation in µTAS.
- To demonstrate the functionality of a thermo-responsive polymer-based microvalve in a cyclic olefin copolymer (COC) microchip.
- To optimize the pressure tolerance and response time of the microvalve.
Main Methods:
- Utilized a quartz halogen illuminator with a tungsten filament to actuate the microvalve.
- Employed poly(N-isopropylacrylamide) (PNIPAAm), a thermo-responsive polymer, within a COC microchip.
- Tuned the mechanical strength of the PNIPAAm monolith by adjusting monomer and crosslinker concentrations.
- Optimized response time and pressure resistance by varying tetrahydrofuran composition during polymerization.
Main Results:
- The light-actuated microvalve demonstrated effective flow path manipulation.
- The PNIPAAm-based microvalve exhibited tunable pressure tolerance.
- Leakage pressure resistance reached approximately 1350 psi.
- Opening and closing response times were measured at 4.0 s and 6.2 s, respectively.
Conclusions:
- A simple, light-actuated microvalve was successfully developed, reducing system complexity in µTAS.
- The microvalve's performance, including pressure tolerance and response time, can be optimized through material composition.
- This technology holds significant potential for applications in drug delivery, chemical analysis, and proteomic analysis.
