Multiscale Porosity Microfluidics to Study Bacterial Transport in Heterogeneous Chemical Landscapes.

Area of Science:

• Porous Media Research
• Microfluidics
• Biogeochemistry

Background:

• Microfluidic models are valuable for studying porous media due to their pore-scale observation capabilities.
• Existing microfluidic models often lack the multiscale porosity found in natural systems like tissues or geological substrates.
• This limitation hinders the accurate simulation of complex transport phenomena.

Purpose of the Study:

• To present a novel microfluidic system capable of replicating multiscale porosity.
• To demonstrate the system's utility in studying heterogeneous fluid flow and chemical transport.
• To investigate biological behaviors influenced by multiscale porosity, such as bacterial chemotaxis.

Main Methods:

• Fabrication of polydimethylsiloxane (PDMS) pillars with varying spacing.
• In-situ photopolymerization of polyacrylamide (PAAm) hydrogel structures within the PDMS pillar landscape.
• Creation of micromodels with porosity ranging from nanometers to millimeters.

Main Results:

• Successful creation of microfluidic models with porosity spanning several orders of magnitude.
• Demonstration of the system's potential for characterizing biological and geochemical transport processes.
• Enabled studies of heterogeneous fluid flow, concentration fields, and bacterial chemotaxis.

Conclusions:

• The developed microfluidic system effectively mimics natural porous media with multiscale porosity.
• This approach enhances the study of complex transport phenomena and associated biological behaviors.
• It brings laboratory-based porous media research closer to real-world environmental, industrial, and medical applications.