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中文核心期刊

多孔水凝胶支架内部变形测量方法研究

RESEARCH ON MEASUREMENT METHOD FOR INTERNAL DEFORMATION OF POROUS HYDROGEL SCAFFOLDS

  • 摘要: 多孔水凝胶支架作为组织工程中临时的细胞外基质, 不仅为种子细胞提供生存的空间支撑, 还将外界力学刺激通过自身结构重新分配, 构建出可以调控细胞生理活动的力学微环境. 然而, 如何定量表征和调控组织工程水凝胶支架内的力学微环境是实现组织原位再生的关键. 针对多孔水凝胶支架内部变形测量的 “半连续”问题, 提出了一种半连续光学相干弹性成像(semi-continuous optical coherence elastography, SC-OCE)变形测量方法, 该方法包括材料组分识别算法、改进的半连续数字体相关(semi-continuous digital volume correlation, SC-DVC)方法和半连续结构应变计算, 解决了多孔支架半连续结构测量中的跨界面子块的不连续变形产生的形函数欠匹配误差和应变拟合窗口跨界面不连续问题. 基于反向映射法的模拟实验结果表明, SC-OCE方法的位移测量的均值绝对误差均小于0.0025体素, 应变测量的均值绝对误差均小于0.0008, 证明该方法具有较高的理论精度. 在SC-OCE变形测量方法的基础上, 定量表征了多孔的丝素蛋白/II型胶原蛋白组织工程支架的变形场, 实验发现不连续结构展现出了非线性及非均匀的应变场. 多孔水凝胶支架构建的力学微环境对于组织原位再生具有不可替代的作用, SC-OCE方法可以为力学微环境调控提供定量依据, 进一步指导组织工程的原位再生.

     

    Abstract: As a temporary extracellular matrix in tissue engineering, porous hydrogel scaffolds not only provide spatial support for the survival of seeded cells but also redistribute external mechanical stimuli through their own structures, thereby constructing a mechanical microenvironment that can regulate the physiological activities of cells. However, how to quantitatively characterize and regulate the mechanical microenvironment within tissue engineering porous hydrogel scaffolds is the key to achieving in situ tissue regeneration. In this paper, aiming at the "semi-continuous" problem in the internal deformation measurement of porous hydrogel scaffolds, a semi-continuous optical coherence elastography (SC-OCE) deformation measurement method is proposed. This method includes a material component identification algorithm, an improved semi-continuous digital volume correlation (SC-DVC) method, and semi-continuous structural strain calculation, which solves the shape function under-matching error caused by the discontinuous deformation of cross-interface sub-blocks and the problem of discontinuity of the strain fitting window across interfaces in the measurement of the semi-continuous structure of porous hydrogel scaffolds. The simulation experiment results based on the backward mapping method show that the mean absolute error of displacement measurement by the SC-OCE method is less than 0.0025 voxels, and the mean absolute error of strain measurement is less than 0.0008, proving that this method has a high theoretical accuracy. Based on the SC-OCE deformation measurement method, the deformation field of the porous silk fibroin and type II collagen tissue engineering scaffold was quantitatively characterized. The experiment found that the discontinuous structure exhibited a nonlinear and non-uniform strain field. The mechanical microenvironment constructed by porous hydrogel scaffolds plays an irreplaceable role in in situ tissue regeneration. The SC-OCE method can provide a quantitative basis for the regulation of the mechanical microenvironment and further guide the in situ regeneration of tissue engineering.

     

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