What are the optimal loading modality values to mechanically stimulate biphasic scaffolds for annulus fibrosis repair?

The correct choice of 6% strain and 1 Hz frequency for mechanically stimulating biphasic scaffolds in annulus fibrosis repair is based on understanding the biomechanical environment necessary for optimal cellular responses during tissue regeneration.

In tissue engineering, particularly for structures such as the annulus fibrosus, the mechanical loading conditions significantly impact cell proliferation, differentiation, and matrix production. The 6% strain is within a physiological range that is conducive to cell signaling processes without causing detrimental effects such as cell death or excessive matrix disruption. This moderate level of strain mimics the natural loading conditions experienced by the annulus fibrosus in the body, thereby promoting a favorable environment for tissue healing and integration.

The frequency of 1 Hz strikes a balance that optimally activates mechanotransductive pathways in the cells. Higher frequencies may induce rapid strain cycles that could lead to fatigue or inadequately simulate the natural physiological conditions under which the annulus fibrosus operates. Thus, the combination of 6% strain and 1 Hz frequency provides a suitable mechanical environment that supports tissue repair while avoiding potential negative outcomes that could arise with higher strain levels or inappropriate frequencies.