Visualization of flow-aligned type I collagen self-assembly in tunable pH gradients

Area of Science:

• Biomaterials Science
• Biophysics
• Chemical Engineering

Background:

• Collagen, a key extracellular matrix component, has a complex hierarchical structure.
• The ex vivo self-assembly process of collagen remains poorly understood, hindering biomaterial development.
• Existing methods lack detailed insights into collagen's dynamic assembly.

Purpose of the Study:

• To develop and validate a microfluidic system for investigating collagen self-assembly dynamics.
• To enable simultaneous, in situ monitoring of collagen assembly at various stages.
• To provide a controllable platform for studying biomacromolecule self-assembly.

Main Methods:

• Utilized a microfluidic device with hydrodynamic focusing to control pH and study collagen-I self-assembly.
• Employed in situ polarization microscopy and X-ray diffraction for real-time characterization.
• Validated experimental findings using finite element method simulations for flow and diffusion analysis.

Main Results:

• The microfluidic system successfully controlled collagen self-assembly dynamics by manipulating pH.
• Continuous extensional flow induced highly ordered collagen phases, enabling non-destructive data collection.
• Simulations accurately described experimental observations of diffusion, flow, and pH distribution.

Conclusions:

• The developed microfluidic system offers a powerful tool for investigating dynamic biomacromolecule self-assembly.
• This approach provides unprecedented control and insight into collagen self-assembly processes.
• The findings have broad implications for the design and fabrication of advanced collagen-based biomaterials.