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Published on: September 10, 2018
Quantitative analysis of molecular absorption into PDMS microfluidic channels.
Jack D Wang1, Nicholas J Douville, Shuichi Takayama
1Department of Biomedical Engineering, University of Michigan, 1101 Beal Avenue, Ann Arbor, MI 48109, USA.
Annals of Biomedical Engineering
|April 10, 2012
Summary
Hydrophobic molecules in poly(dimethylsiloxane) (PDMS) microfluidic devices can diffuse into channel walls, affecting assay accuracy. Coatings like TiO(2) and glass significantly reduce this absorption, improving reliability for in vitro cell culture.
Area of Science:
- Biomaterials Science
- Analytical Chemistry
- Cell Biology
Background:
- Poly(dimethylsiloxane) (PDMS) microfluidic devices are widely used for in vitro cell culture and assays.
- Assay accuracy relies on consistent solute concentrations, but hydrophobic molecules can be absorbed by PDMS.
- This absorption reduces molecule concentration, impacting assay reliability and reproducibility.
Purpose of the Study:
- To quantitatively investigate the relationship between solute partition coefficient (log P) and absorption into PDMS microfluidic channels.
- To determine the impact of solute hydrophilicity/hydrophobicity on PDMS absorption.
- To evaluate the effectiveness of TiO(2) and glass coatings in reducing hydrophobic molecule absorption.
Main Methods:
- Utilized a series of fluorescent and radiolabeled markers with varying partition coefficients (log P) for absorption studies.
- Quantified solute absorption into standard PDMS microfluidic channels.
- Assessed the reduction in hydrophobic molecule absorption using PDMS channels coated with TiO(2) and glass.
Main Results:
- Solute absorption into PDMS is strongly correlated with the partition coefficient (log P).
- Molecules with log P < 2.47 showed minimal (<10%) absorption, while those with log P > 2.62 exhibited extensive (>90%) absorption.
- TiO(2) and glass coatings reduced hydrophobic molecule absorption by 2-fold and 4.5-fold, respectively.
Conclusions:
- The hydrophilic-hydrophobic balance, indicated by log P, dictates solute absorption in PDMS microfluidics.
- Coating PDMS channels with TiO(2) or glass is an effective strategy to mitigate the absorption of hydrophobic molecules.
- These findings are crucial for improving the accuracy and reliability of microfluidic-based cellular assays.
