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Surface modification of poly(dimethylsiloxane) microchips using a double-chained cationic surfactant for efficiently
Bingyan Han1, Yuanhong Xu, Lixue Zhang
1State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Changchun, Jilin 130022, China.
Didodecyldimethylammonium bromide (DDAB) dynamically modifies poly(dimethylsiloxane) microchips, preventing fluorescent dye adsorption and reversing electroosmotic flow. This surfactant enables improved separations of hydrophobic compounds on microfluidic devices.
Area of Science:
- Analytical Chemistry
- Materials Science
- Microfluidics
Background:
- Poly(dimethylsiloxane) (PDMS) microchips are susceptible to fluorescent dye adsorption, hindering their analytical applications.
- Dynamic surface modification is crucial for optimizing microchip performance in capillary electrophoresis.
- Cationic surfactants offer potential for surface modification but require careful selection for optimal results.
Purpose of the Study:
- To investigate the efficacy of didodecyldimethylammonium bromide (DDAB) for dynamic surface modification of PDMS microchips.
- To assess DDAB's impact on electroosmotic flow (EOF) and fluorescent dye adsorption.
- To evaluate DDAB's performance in separating hydrophobic compounds.
Main Methods:
- Dynamic surface modification of PDMS microchips using didodecyldimethylammonium bromide (DDAB) in buffer solutions.
- Investigation of factors influencing modification, including pH and DDAB concentration.
- Capillary electrophoresis (CE) experiments to assess EOF reversal and dye adsorption suppression.
- Separation of fluorescent dyes pyronine Y (PY) and rhodamine B (RB) on modified microchips.
Main Results:
- DDAB effectively suppressed the adsorption of fluorescent dyes (PY and RB) onto PDMS microchip surfaces.
- High concentrations of DDAB reversed the direction of electroosmotic flow.
- DDAB-formed vesicles enhanced separation efficiency and broadened the migration window for hydrophobic compounds.
- DDAB demonstrated superior modification performance compared to cetyltrimethylammonium bromide (CTAB).
Conclusions:
- Didodecyldimethylammonium bromide (DDAB) is a highly effective surfactant for dynamic surface modification of PDMS microchips.
- DDAB-based modification enables robust suppression of dye adsorption and controlled EOF.
- The developed method facilitates the separation of challenging hydrophobic analytes in microfluidic systems.
