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Optimization of poly(dimethylsiloxane) hollow prisms for optical sensing
A Llobera1, R Wilke, S Büttgenbach
1Institut für Mikrotechnik, Technische Universität Braunschweig, Alte Salzdahlumer Strasse 203, 38124 Braunschweig, Germany. a.llobera@tu-bs.de
Lab on a Chip
|April 28, 2005
Summary
This study introduces compact microfluidic systems using hollow prisms for optical detection. These systems achieve lower detection limits for fluorescein and methylorange, demonstrating their utility for chemical sensing and pH measurement.
Area of Science:
- Microfluidics
- Optical Sensing
- Analytical Chemistry
Background:
- Microfluidic devices offer miniaturized platforms for chemical analysis.
- Optical readout methods provide sensitive detection capabilities.
- Integration of components is key for robust and compact systems.
Purpose of the Study:
- To develop and optimize simple, robust, and compact microfluidic systems with optical readout.
- To enhance the limit of detection (LOD) for specific analytes.
- To demonstrate the application of these systems for pH measurements.
Main Methods:
- Fabrication of hollow prisms using soft-lithography.
- Integration of microlenses and fiber optic positioning channels for monolithic design.
- Optical absorption measurements at a working wavelength of 460 nm.
- Optimization of prism volume and geometry.
Main Results:
- Achieved significantly lowered LOD for fluorescein and methylorange in the microM range.
- Demonstrated improved LOD by increasing prism size and total deviation angle.
- Validated the Beer-Lambert law for the tested concentrations.
- Successfully utilized the system for pH measurements based on methylorange absorption changes.
Conclusions:
- The developed microfluidic systems are simple, robust, and compact, suitable for optical sensing.
- Optimization of geometric parameters enhances detection sensitivity.
- The system shows promise for quantitative chemical analysis and pH monitoring.