Microengineering 3D Collagen Matrices with Tumor-Mimetic Gradients in Fiber Alignment.

Area of Science:

• Biomaterials Science
• Cell Biology
• Biophysics

Background:

• Collagen fiber alignment in the tumor microenvironment (TME) directs cell migration via contact guidance.
• Previous studies focused on uniform fiber alignments, neglecting physiological alignment gradients found in the TME.
• Cellular responses to these natural alignment gradients remain largely unexplored.

Purpose of the Study:

• To characterize and recreate physiological collagen fiber alignment gradients.
• To investigate cell migration responses to engineered continuous alignment gradients in biomaterials.
• To explore the role of alignment gradients as a biophysical taxis cue.

Main Methods:

• Characterization of fiber alignment gradients in biopsy samples.
• Development of a microfluidic biofabrication technique for tunable alignment gradients.
• In vitro migration assays using human umbilical vein endothelial cells (HUVECs) and MDA-MB-231 cancer cell aggregates.

Main Results:

• Successful engineering of continuous collagen alignment gradients in soft biomaterials.
• HUVECs demonstrated increased migration directionality, persistence, and speed on graded alignments compared to uniform or unaligned fibers.
• MDA-MB-231 aggregates exhibited biased migration towards regions of increasing fiber alignment.

Conclusions:

• Engineered alignment gradients mimic physiological conditions and serve as a taxis cue for cell migration.
• This approach provides new insights into how cells interpret biophysical cues within the extracellular matrix.
• The user-friendly technique has broad applicability for studying cell behavior in various tissue environments.