Biophysical Society Thematic Meeting | Riga 2026

Active and Responsive Soft Matter: From Biological to Engineered Systems

Thursday Speaker Abstracts

SOLID STRESS AND ITS RELATIONSHIP TO CELL AND MATRIX ORGANIZATION Rebecca Wells 1 ; 1 University of Pennsylvania, Philadelphia, PA, USA

Solid stress is the term applied to the mechanical forces generated and transmitted by the solid components of a tissue. It consists of residual solid stress, which is internally generated and stored within the structural components of a tissue or tumor, and externally-applied solid stress, reflecting the reciprocal forces from surrounding tissue or the outermost cells of the tissue or tumor. High solid stress has functional implications including impaired DNA repair with genomic instability and increased migration and invasion. Solid stress is nearly zero in normal tissues, but elevated levels are typical of both benign and malignant tumors. We present here a method to use 3D deformation mapping to measure solid stress even in highly heterogeneous tissues. We used as an example liver cirrhosis, a premalignant state defined by complete enclosure of nodules of hepatocytes by fibrotic septae. We found that cirrhotic livers had markedly elevated solid stress. After thin planar slicing, there were reciprocal deformations in the cellular components of the nodule and in the collagen/hyaluronic acid-rich surrounding septae. To define mechanisms of externally-applied solid stress, we treated with collagenase or hyaluronidase. Both markedly reduced solid stress, consistent with external stress arising from the matrix; by imaging septal collagen by second harmonics generation and taking a fluid mechanics approach to analysis, we showed that collagen is organized in a high energy conformation. For residual solid stress, cell-size analysis and demonstration that vasculature was mostly absent in the center of the nodules were consistent with chemo-osmotic stress as a cause of residual solid stress, as has recently been modeled by others (PMID: 41676463). Proliferation was minimal, suggesting it does not contribute significantly to generation of solid stress.

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