Defining Multiscale, Rate-Dependent Damage Mechanisms in Blood Vessels

血管可能会由于大的形状变化而受损-变形-发生在事故（如创伤性脑损伤）和手术（如血管成形术）中。 然而，人们对这种损伤如何影响血管继续发挥其功能的能力知之甚少。 当损伤轻微且没有出血时尤其如此。此外，最近的研究表明，变形率会影响所产生的损坏类型。该项目的目标是确定血管损伤机制，并确定损伤如何改变血管功能。该项目的重点是大脑中的血管。该项目的结果将提供有关创伤性脑损伤损伤机制的见解，并可能最终导致更好的医疗保健治疗。这些信息将改善汽车、头盔和其他防护装置的设计标准。它还可能揭示脑损伤后增加中风风险的因素。它还可以改善球囊血管成形术的结果。参与本项目的研究人员将包括来自代表性不足群体的学生，他们将获得有价值的专业发展。本项目的目的是（1）区分和量化血管软化的可恢复（例如粘弹性）和不可恢复（例如胶原展开）机制的贡献，（2）定义应变率对损伤机制的影响。微结构损伤和相关的软化将使用通过一系列应变率过度拉伸的孤立血管来定义。实验结果将被纳入一个新的本构模型，涉及多尺度损伤的被动血管成分的机械行为。这是预测疾病发展和/或损伤后恢复的关键第一步。虽然研究重点是血管，但研究结果预计也适用于其他软组织。研究结果将推进损伤预防策略，并为介入手术和植入式生物材料和器械的优化设计提供基础。这些实验将为预测损伤引起的血管行为变化的计算机模型提供信息。最后，该研究将进一步开发表征软组织损伤的方法，包括胶原蛋白杂交肽来量化胶原蛋白损伤。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Blood vessels can be damaged as a result of large shape changes – deformations – that occur in both accidents (such as traumatic brain injury) and surgery (such as angioplasty). However, little is known about how this damage affects a vessel’s ability to continue to perform its function. This is especially true when damage is subtle and there is no bleeding. Additionally, recent research shows that the rate of deformation influences the type of resulting damage. The goals of this project are to define damage mechanisms in blood vessels and to define how damage changes vessel function. The project focuses on blood vessels in the brain. The results of this project will provide insight about damage mechanisms in traumatic brain injury, and may eventually lead to better healthcare treatments. This information will improve design criteria for automobiles, helmets, and other protective devices. It may also reveal factors that increase the risk of stroke after brain injury. It may also improve outcomes of balloon angioplasty procedures. Researchers involved in this project will include students from underrepresented groups, who will gain valuable professional development.The aims of this project are (1) to differentiate and quantify contributions of both recoverable (e.g. viscoelasticity) and non-recoverable (e.g. collagen unfolding) mechanisms of vessel softening, and (2) to define the influence of strain rate on mechanisms of damage. Microstructural damage and associated softening will be defined using isolated blood vessels subjected to overstretch through a range of strain rates. Experimental findings will be incorporated into a novel constitutive model that relates multiscale damage of passive vessel constituents with mechanical behavior. This is a critical first step toward predicting disease development and/or recovery after injury. While the research focuses on blood vessels, findings are expected to also apply to other soft tissues. Results will advance injury prevention strategies and provide a foundation for optimization of design for both interventional procedures and implantable biomaterials and devices. These experiments will inform computer models that predict damage-induced changes in vessel behavior. Finally, the research will further develop methods for characterizing soft tissue damage, including collagen hybridizing peptide to quantify collagen damage.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.