IEEE Trans Biomed Eng. 2023 Mar;70(3):841-852. doi: 10.1109/TBME.2022.3203435. Epub 2023 Feb 17.
OBJECTIVE: Hydrogel scaffolds have attracted attention to develop cellular therapy and tissue engineering platforms for regenerative medicine applications. Among factors, local mechanical properties of scaffolds drive the functionalities of cell niche. Dynamic mechanical analysis (DMA), the standard method to characterize mechanical properties of hydrogels, restricts development in tissue engineering because the measurement provides a single elasticity value for the sample, requires direct contact, and represents a destructive evaluation preventing longitudinal studies on the same sample. We propose a novel technique, acoustic force elastography microscopy (AFEM), to evaluate elastic properties of tissue engineering scaffolds. RESULTS: AFEM can resolve localized and two-dimensional (2D) elastic properties of both transparent and opaque materials with advantages of being non-contact and non-destructive. Gelatin hydrogels, neat synthetic oligo[poly(ethylene glycol)fumarate] (OPF) scaffolds, OPF hydroxyapatite nanocomposite scaffolds and ex vivo biological tissue were examined with AFEM to evaluate the elastic modulus. These measurements of Young's modulus range from approximately 2 kPa to over 100 kPa were evaluated and are in good agreement with finite element simulations, surface wave measurements, and DMA tests. CONCLUSION: The AFEM can resolve localized and 2D elastic properties of hydrogels, scaffolds and thin biological tissues. These materials can either be transparent or non-transparent and their evaluation can be done in a non-contact and non-destructive manner, thereby facilitating longitudinal evaluation. SIGNIFICANCE: AFEM is a promising technique to quantify elastic properties of scaffolds for tissue engineering and will be applied to provide new insights for exploring elastic changes of cell-laden scaffolds for tissue engineering and material science.
目的:水凝胶支架吸引了人们的关注,以开发细胞治疗和组织工程平台,用于再生医学应用。在诸多因素中,支架的局部力学性能驱动着细胞生态位的功能。动态力学分析(DMA)是一种用于表征水凝胶力学性能的标准方法,但它限制了组织工程的发展,因为该测量方法仅为样品提供一个弹性值,需要直接接触,并且是一种破坏性评估,无法对同一样品进行纵向研究。我们提出了一种新的技术,即声力弹性显微镜(AFEM),用于评估组织工程支架的弹性特性。
结果:AFEM 可以分辨透明和不透明材料的局部和二维(2D)弹性特性,具有非接触和无损的优点。我们使用 AFEM 对明胶水凝胶、纯合成寡聚[聚(乙二醇)琥珀酸酯](OPF)支架、OPF 羟基磷灰石纳米复合材料支架和离体生物组织进行了弹性测量,以评估弹性模量。这些杨氏模量的测量值约为 2 kPa 到 100 kPa 以上,与有限元模拟、表面波测量和 DMA 测试结果吻合较好。
结论:AFEM 可以分辨水凝胶、支架和薄生物组织的局部和 2D 弹性特性。这些材料可以是透明的也可以是不透明的,它们的评估可以采用非接触和无损的方式进行,从而便于进行纵向评估。
意义:AFEM 是一种很有前途的技术,可以定量测量组织工程支架的弹性特性,并将应用于为组织工程和材料科学探索细胞负载支架的弹性变化提供新的见解。
IEEE Trans Biomed Eng. 2023-3
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