Li Weiping, Hobson Eric C, Downey Kiera, Hall Timothy L, Stegemann Jan P, Deng Cheri X
Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.
Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA; Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA.
Biomaterials. 2025 Oct;321:123325. doi: 10.1016/j.biomaterials.2025.123325. Epub 2025 Apr 8.
Accurately measuring the viscoelastic properties of biomaterials is critical for understanding their functions in biological systems and optimizing their development for specific applications. Conventional methods often require direct physical contact, which hinders longitudinal studies of sterile samples and impose strict requirements in sample preparation. Here, we introduce tensile acoustic rheometry (TAR), a technique for rapid, contactless characterization of soft viscoelastic biomaterials. TAR uses a dual-mode ultrasound approach to apply an upward force impulse, generating oscillatory tensile and compressive motion in a small, free-standing sample (∼30 mm) with its bottom immobilized on a pre-wetted flat surface by capillary stiction. High frequency ultrasound pulse echo detection is employed to track this motion via the movement of the top surface of the sample in real time. In this study, we developed a theoretical framework of the tensile-compression motion of the sample from which Young's modulus and viscosity of the sample are determined based on the TAR measurements. TAR was validated across a variety of samples, including engineered hydrogels and commercially available natural food products. Results from TAR measurements aligned closely with theoretical predictions, reported values, and shear wave elastography measurements. These findings underscore the versatility and flexibility of TAR as a robust, versatile rheological method for biomaterial characterization with minimal sample preparation requirements.
准确测量生物材料的粘弹性特性对于理解其在生物系统中的功能以及优化其在特定应用中的开发至关重要。传统方法通常需要直接物理接触，这阻碍了对无菌样品的纵向研究，并对样品制备提出了严格要求。在此，我们介绍拉伸声学流变学（TAR），一种用于快速、非接触式表征软粘弹性生物材料的技术。TAR采用双模式超声方法施加向上的力脉冲，在一个小的独立样品（约30毫米）中产生振荡拉伸和压缩运动，该样品底部通过毛细粘附固定在预先湿润的平面上。采用高频超声脉冲回波检测通过实时跟踪样品顶面的运动来追踪此运动。在本研究中，我们建立了样品拉伸-压缩运动的理论框架，基于TAR测量从中确定样品的杨氏模量和粘度。TAR在包括工程水凝胶和市售天然食品在内的各种样品上得到了验证。TAR测量结果与理论预测、报告值以及剪切波弹性成像测量结果密切吻合。这些发现强调了TAR作为一种强大、通用的流变学方法用于生物材料表征的多功能性和灵活性，其对样品制备的要求极低。
