Stressed polystyrene causes increased membrane sensitivity of adherent cells to fluid shear force: technical note

Area of Science:

• Cell Biology
• Materials Science
• Biophysics

Background:

• Adherent cells respond to extracellular matrix signals, influencing cell functions like spreading and morphology.
• The impact of substratum adherence on cell membrane mechanical properties remains understudied.
• Nara Bladder Tumour (NBT) II cells exhibit differential responses on polystyrene (PS) discs compared to their centers and surrounding glass surfaces.

Purpose of the Study:

• To investigate changes in cell membrane mechanical properties due to adherence to a substratum.
• To examine the effect of substrate stress on cell death under mechanical force.
• To explore the relationship between substrate birefringence, lipophilicity, and cell membrane sensitivity.

Main Methods:

• Utilized Live/Dead cell assay to quantify cell death after fluid shear force application.
• Employed cross-polarized light microscopy to assess birefringence in polystyrene discs.
• Applied controlled stress and temperature changes to polystyrene discs to induce birefringence and altered lipophilicity (Nile Red staining).

Main Results:

• Cells on the peripheral zone of unstressed PS discs showed significantly higher death rates (91.1%) under shear force compared to cells on the center (7.1%) or glass (4.3%).
• Stressing the PS discs induced birefringence and increased lipophilicity.
• NBT II cells on stressed PS discs exhibited increased cell death (55.8%) under shear force compared to unstressed PS (91.1%) or glass (5.0%).

Conclusions:

• Adherence to stressed polystyrene alters cell membrane properties, increasing sensitivity to mechanical forces.
• Induced birefringence and lipophilicity in stressed PS are associated with altered cell membrane mechanics and increased cell death.
• The study highlights the critical role of substrate material properties and stress in cellular responses to mechanical stimuli.