Related Experiment Video
Updated: Oct 7, 2025
Protocol for Biofilm Streamer Formation in a Microfluidic Device with Micro-pillars
Published on: August 20, 2014
Effects of Hydrophilicity, Adhesion Work, and Fluid Flow on Biofilm Formation of PDMS in Microfluidic Systems
Jinling Zhu1, Minqi Wang2, Hongbo Zhang1
1School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China.
Abstract:
Polydimethylsiloxane (PDMS) has been the most widely used material in microfluidic systems, especially for cell biology applications. However, the antibacterial performance of PDMS in flow conditions has never been reported in the literature. In this paper, we analyzed the effects of contact angle (CA), adhesion force (work), and surface free energy on the antibacterial activities of PDMS by varying the ratio of curing agents (crosslinking degree) and surface modification with oxygen plasma. The results show that the Young's modulus has no particular effects on bacterial adhesion compared to the CAs of samples. For the first time, we analyzed the adhesion work (AW) effect on biofilm formation, and we found that biofilms tend to form on the surface with less AW. Furthermore, we analyzed the dual effect of hydrophilicity and shear force induced by fluid flow on the bacterial adhesion in PDMS microfluidic systems. We found that at low flow rates in microfluidic conditions, the adhesion of the bacteria on the PDMS surface is inhibited when the fluid flow exceeds a certain value. It required higher shear force to inhibit bacterial adhesion on the hydrophilic surface than on the hydrophobic surface. Therefore, hydrophilicity might be the dominant factor affecting bacterial adhesion.
Insights
Polydimethylsiloxane (PDMS) surfaces in microfluidics show reduced bacterial adhesion with increased fluid flow. Hydrophilicity and adhesion work, not Young
Area of Science:
- Microfluidics
- Biomaterials
- Surface Science
Background:
- Polydimethylsiloxane (PDMS) is a prevalent material in microfluidic devices, particularly for cell biology.
- The antibacterial properties of PDMS under flow conditions remain largely unexplored.
- Understanding bacterial adhesion on PDMS is crucial for preventing biofilm formation in microfluidic applications.
Purpose of the Study:
- To investigate the influence of surface properties and fluid flow on antibacterial performance of PDMS.
- To analyze the impact of contact angle, adhesion work, and surface free energy on bacterial adhesion.
- To determine the role of hydrophilicity and shear force in inhibiting bacterial adhesion in microfluidic systems.
Main Methods:
- PDMS samples were prepared with varying crosslinking degrees and oxygen plasma surface modifications.
- Contact angle, adhesion force (work), and surface free energy were measured.
- Bacterial adhesion and biofilm formation were assessed under different fluid flow rates in microfluidic channels.
- The effect of shear force and surface hydrophilicity on bacterial adhesion was analyzed.
Main Results:
- Young's modulus did not significantly affect bacterial adhesion; contact angle was more influential.
- Biofilm formation was reduced on surfaces with higher adhesion work.
- Increased fluid flow shear force inhibited bacterial adhesion on PDMS surfaces.
- Hydrophilic PDMS surfaces required greater shear force to prevent bacterial adhesion compared to hydrophobic surfaces.
Conclusions:
- Hydrophilicity appears to be a dominant factor in controlling bacterial adhesion on PDMS microfluidic devices.
- Surface properties like adhesion work and contact angle, alongside fluid dynamics, are critical for managing bacterial contamination.
- This study provides novel insights into the antibacterial performance of PDMS under flow, essential for microfluidic system design.
