PT  - JOURNAL ARTICLE
AU  - Hannah Varner
AU  - Gabriella P. Sugerman
AU  - Manuel K. Rausch
AU  - Tal Cohen
TI  - Elasticity of Whole Blood Clots Measured via Volume Controlled Cavity Expansion
AID  - 10.1101/2023.02.17.528966
DP  - 2023 Jan 01
TA  - bioRxiv
PG  - 2023.02.17.528966
4099  - http://biorxiv.org/content/early/2023/02/21/2023.02.17.528966.short
4100  - http://biorxiv.org/content/early/2023/02/21/2023.02.17.528966.full
AB  - Measuring and understanding the mechanical properties of blood clots can provide insights into disease progression and the effectiveness of potential treatments. However, several limitations hinder the use of standard mechanical testing methods to measure the response of soft biological tissues, like blood clots. These tissues can be difficult to mount, and are inhomogeneous, irregular in shape, scarce, and valuable. To remedy this, we employ in this work Volume Controlled Cavity Expansion (VCCE), a technique that was recently developed, to measure local mechanical properties of soft materials in their natural environment. Through a highly controlled volume expansion of a water bubble at the tip of an injection needle, paired with simultaneous measurement of the resisting pressure, we obtain a local signature of whole blood clot mechanical response. Comparing this data with predictive theoretical models, we find that a 1-term Ogden model is sufficient to capture the nonlinear elastic response observed in our experiments and produces shear modulus values that are comparable to values reported in the literature. Moreover, we find that bovine whole blood stored at 4°C for greater than 2 days exhibits a statistically significant shift in the shear modulus from 2.53 ± 0.44 kPa on day 2 (N = 13) to 1.23 ± 0.18 kPa on day 3 (N = 14). In contrast to previously reported results, our samples did not exhibit viscoelastic rate sensitivity within strain rates ranging from 0.22 – 21.1 s−1. By surveying existing data on whole blood clots for comparison, we show that this technique provides highly repeatable and reliable results, hence we propose the more widespread adoption of VCCE as a path forward to building a better understanding of the mechanics of soft biological materials.Competing Interest StatementThe authors have declared no competing interest.