Novel mechanical bioreactor for concomitant fluid shear stress and substrate strain

Area of Science:

• Biomedical Engineering
• Cellular Mechanobiology
• Skeletal Biology

Background:

• Bone mechanotransduction studies utilize substrate strain and flow-induced shear stress.
• Previous studies have limitations in quantitatively measuring stimuli and controlling cellular environments.
• No existing bioreactors apply substrate strain and flow-induced shear stress simultaneously and differentially.

Purpose of the Study:

• To design and validate a multimodal loading device for bone mechanotransduction research.
• To enable simultaneous application of substrate strain and flow-induced shear stress.
• To allow for real-time cell imaging during mechanical stimulation.

Main Methods:

• Designed a novel bioreactor capable of applying substrate stretch and fluid flow concurrently.
• Validated the bioreactor's mechanical performance by correlating input (displacement, displacement rate) with output (shear stress, substrate strain).
• Characterized cross-talk loading (flow-induced strain, strain-induced fluid flow).

Main Results:

• The multimodal loading device successfully applies substrate stretch and fluid flow simultaneously.
• Mechanical performance was validated, showing correlation between input and output mechanical stimuli.
• Cross-talk loading magnitudes were found to be significantly lower than in vivo physiological levels.

Conclusions:

• The developed bioreactor provides a powerful tool for investigating bone mechanotransduction.
• This device overcomes previous experimental limitations by enabling controlled, simultaneous application of multiple mechanical stimuli.
• The findings support the potential for more accurate and comprehensive studies of bone cell responses to mechanical loading.