Biology subjects

Bonassar, L. J.

Publications and source records attributed to Bonassar, L. J..

2 recordsLinked to original sources

bioRxiv2024

3D in-situ characterization reveals the instability-induced auxetic behavior of collagen scaffolds for tissue engineering

Collagen scaffolds seeded with human chondrocytes have shown great potential for cartilage repair and regeneration. However, these porous scaffolds buckle under low compressive forces, creating regions of highly localized deformations that can cause cell death and deteriorate the integrity of the engineered tissue. We perform three-dimensional (3D) tomography-based characterization to track the evolution of collagen scaffolds microstructure under large deformation. The results illustrate how instabilities produce a spatially varying compaction across the specimens, with more pronounced collapse near the free boundaries. We discover that, independent of differences in pore-size distributions, all collagen scaffolds examined displayed strong auxetic behavior i.e., their transverse area contracts under compression, as a result of the instability cascade. This feature, typically characteristic of engineered metamaterials, is of critical importance for the performance of collagen scaffolds in tissue engineering, especially regarding the persistent challenge of lateral integration in cartilage constructs.

bioengineering↗

bioRxiv2022

STRAINS: A Big Data Method for Classifying Cellular Response to Stimuli at the Tissue Scale

Cellular response to stimulation governs tissue scale processes ranging from growth and development to maintaining tissue health and initiating disease. To determine how cells coordinate their response to such stimuli, it is necessary to simultaneously track and measure the spatiotemporal distribution of their behaviors throughout the tissue. Here, we report on a novel SpatioTemporal Response Analysis IN Situ (STRAINS) tool that uses fluorescent micrographs, cell tracking, and machine learning to measure such behavioral distributions. STRAINS is broadly applicable to any tissue where fluorescence can be used to indicate changes in cell behavior. For illustration, we use STRAINS to simultaneously analyze the mechanotransduction response of 5000 chondrocytes--over 20 million data points--in cartilage during the 50 ms to 4 hours after the tissue was subjected to local mechanical injury, known to initiate osteoarthritis. We find that chondrocytes exhibit a range of mechanobiological responses indicating activation of distinct biochemical pathways with clear spatial patterns related to the induced local strains during impact. These results illustrate the power of this approach.

biophysics↗