A simple fabricated thickness-based stiffness gradient for cell studies.

Area of Science:

• Biomaterials Engineering
• Cell Biology
• Pharmacology

Background:

• Cellular behavior and drug responses are significantly influenced by the mechanical properties of their surrounding microenvironment.
• Existing methods for creating stiffness gradients often require specialized equipment, limiting accessibility in general laboratories.

Purpose of the Study:

• To develop a simple, cost-effective method for fabricating a continuous stiffness gradient substrate.
• To investigate the impact of substrate stiffness on cell morphology and drug efficacy.
• To provide a tool for more physiologically relevant cell studies and drug screening.

Main Methods:

• Fabrication of a stiffness gradient using readily available materials: glass slides, polydimethylsiloxane (PDMS) pre-polymer, spacers, and clips.
• Characterization of the apparent Young's modulus using atomic force microscopy (AFM), revealing a range of 8.5-120 kPa.
• Culturing of HeLa-C3 cells on the gradient to observe morphological changes and assess drug sensitivity.

Main Results:

• A continuous stiffness gradient with a physiologically relevant Young's modulus range (8.5-120 kPa) was successfully fabricated.
• HeLa-C3 cell morphology exhibited dependence on substrate stiffness.
• Enhanced sensitivity to the anti-cancer drug etoposide was observed in cells cultured on softer regions of the gradient (8.5-11 kPa).

Conclusions:

• The developed method offers a simple and accessible approach to creating stiffness gradient materials for biological research.
• The findings highlight the critical role of substrate stiffness in modulating cell response to anti-cancer drugs.
• This technology has the potential to advance cell-based assays and drug screening platforms by mimicking native tissue mechanics.