A simplified yet enhanced and versatile microfluidic platform for cyclic cell stretching on an elastic polymer

Area of Science:

• Biomaterials Science
• Microfluidics
• Cell Biology

Background:

• Traditional microfluidic chips for cell stretching and observation typically consist of three layers.
• Existing designs face challenges with unstable cell focusing during mechanical stretching, hindering real-time microscopic observation.

Purpose of the Study:

• To develop and validate a simplified two-layer microfluidic chip for cell stretching and observation.
• To overcome the inherent difficulties of cell focusing instability in simpler microfluidic designs.

Main Methods:

• Device parameters were optimized using finite element analysis and orthogonal experimental design.
• A novel two-layer microfluidic chip was fabricated and tested for frequency and stretching capabilities.
• Uniaxial stretching experiments were conducted on human mesenchymal stem cells (hMSCs) cultured on polydimethylsiloxane.

Main Results:

• The two-layer chip successfully operated at frequencies up to 2 Hz and stretching ratios up to 20%.
• Human mesenchymal stem cells oriented perpendicular to the stretching direction.
• The chip's short working distance facilitated clear observation of cellular structures like microtubules and stress fibers.

Conclusions:

• The simplified two-layer microfluidic chip offers enhanced and versatile functions compared to previous designs.
• This work presents a novel methodology for fabricating microfluidic chips for studying cellular responses to mechanical stimuli on biomaterials.