Gradient Strain Chip for Stimulating Cellular Behaviors in Cell-laden Hydrogel

Area of Science:

• Tissue Engineering
• Biomaterials Science
• Cellular Mechanics

Background:

• Artificial guidance of cellular alignment is crucial in tissue engineering.
• Previous methods for strain-induced cellular alignment are complex and prone to contamination.
• A need exists for simpler, controlled methods to study cell behavior under mechanical stimuli.

Purpose of the Study:

• To develop a simple, instrument-free approach for creating gradient static strain in 3D hydrogels.
• To investigate cellular alignment in response to engineered microenvironments with varying mechanical strains.
• To understand the interplay between hydrogel geometry and strain in directing cell behavior.

Main Methods:

• Fabrication of a fluidic chip using a polydimethylsiloxane (PDMS) cover and glass substrate.
• Generation of a convex curved PDMS membrane by overloading photo-patternable prepolymer.
• Creation of a gradient static strain microenvironment through UV crosslinking and buffer washing.
• Observation of NIH3T3 cell alignment in 3D hydrogels under strains ranging from 15-65%.

Main Results:

• A self-established microenvironment for gradient strain stimulation was created within a single fluidic chip.
• Cellular alignment trends were observed under combined geometry and strain guidance.
• Hydrogel geometry dictated cell alignment at low compressive strain.
• Cells aligned with hydrogel elongation under high compressive strain.
• Random cell alignment occurred at intermediate strains due to competing guidance cues.

Conclusions:

• The developed fluidic chip offers a simple and effective method for generating gradient static strain in 3D hydrogels.
• This approach facilitates the study of cell behavior and alignment under controlled mechanical stimuli.
• Findings provide insights into how mechanical cues influence cell organization in engineered tissues.