<em>In Silico</em> Model for Determination of<em> In Vivo</em> Pre-Stretch in Neonatal and Adult Murine Cranial Dura Mater

<p>Cranial dura mater is a dense interwoven vascular connective tissue that protects the brain and helps regulate neurocranial remodeling during head development. <em>In vivo</em> investigations indicate that the tissue mediates cranial suture fusion by responding to strains from the growing brain. <em>Ex vivo </em>experimentation has attempted to characterize the mechanical properties that make the dura an effective mechanoreceptor and mechanotransmitter; however, they fail to capture key characteristics of the dura <em>in vivo</em>, such as the impact of tissue pre-stretch. Residual strain, or pre-stretch, is an important quality of many biological tissues, and when not accurately captured by <em>ex vivo</em> experiments, generally leads to underestimation of mechanical stiffness. Considering the importance and lacking characterization of dural pre-stretch, this study aimed to create a robust <em>in silico</em> model for determination of <em>in vivo</em> pre-stretch in neonatal and adult murine cranial dura mater. Transverse and longitudinal incisions were performed <em>ex vivo</em> in the parietal dura of newborn (day ∼4) and mature (day 60+) mice. <em>In silico</em> models of incised neonatal and adult dura experiencing isotropic stretching in the plane transverse to the model’s surface normal were simulated in Abaqus/Standard. The <em>ex vivo</em> and <em>in silico</em> incision opening ratios (opening width over length) were compared, allowing the <em>in vivo</em> in-plane pre-stretch to be determined. Images of cut openings and estimations of pre-stretch indicate the dural pre-stretch is direction-dependent. Differences in neonatal and adult pre-stretch provided further insight into the age-dependency of murine cranial dura mater pre-stretch.</p>