Non-Destructive Vacuum-Assisted Measurement of Lung Elastic Modulus

Abstract

In living tissues, mechanical stiffness and biological function are intrinsically linked. Alterations in the stiffness of tissues can induce pathological interactions that affect cellular activity and tissue function. Underlying connections between tissue stiffness and disease highlights the importance of accurate quantitative characterizations of soft tissue mechanics, which can improve our understanding of disease and inform therapeutic development. In particular, accurate measurement of lung mechanical properties has been especially challenging due to the anatomical and mechanobiological complexities of the lung. Discrepancies between measured mechanical properties of dissected lung tissue samples and intact lung tissues in vivo has limited the ability to accurately characterize integral lung mechanics. Here, we report a non-destructive vacuum-assisted method to evaluate the stiffness of soft biomaterials, including intact tissues and hydrogels. Using this approach, we determined that the elastic modulus of rat lung ranges from 4.44 ± 0.61 to 13.17 ± 3.85 kPa depending on pre-loading conditions. We also observed that the elastic modulus of acutely injured lung tissue increased by at least 64%. The reported methodology enables assessment of the biophysical properties of intact lungs under normal and abnormal (i.e., injured, diseased) conditions and allows measurement of mechanical properties of tissue-mimetic biomaterials for use in therapeutics or in vitro models.