准静态平面均匀流场培养条件下组织工程皮肤生长代谢的数学模型

We have developed the novel perfusion culture device called quasi-static plane homogeneous flow field device according to the characteristics and unique culture requirements of tissue-engineered skin. Based on simulations using computational fluid dynamics and on experimental evaluation, our results showed that at 80-160 ml/min the device can provide a quasi-static plane homogeneous flow field environment suitable for culturing tissue-engineered skin. However, the interaction between the tissue and environment is very complex in the device, and the pattern of nutrients transfer is various, including convection, diffusion, penetration and so on. In order to clarify these complex relationships, this study will adopt unstructured kinetic model combine with experiment to develop mathematical models for the growth and metabolism of the tissue-engineered skin at our flow field. The optimal mathematical model parameters of the global convergence were obtained by non-linear programming of experimental data using MATLAB software. By comparing the fitting situation of the model predicted values and measured values, and experimental evaluating the culture effect of tissue-engineered skin, ultimately make the model can truly reflect the inherent laws of flow field, nutrients transfer and substrate impact on the growth and metabolism of the cell inside the scaffold. This study will provide a theoretical basis for making the control strategy of perfusion culture, estimating the fed formula of medium, harvest the engineered skin and optimizing control of the culture process. And also provide a reference for further expansion production of tissue-engineered skin and mathematical modelling of other engineering tissues.

根据组织工程皮肤自身特点和培养的特殊要求，我们已成功研制出准静态平面均匀流场灌注培养装置，基于计算流体动力学分析和实测结果显示：80-160ml/min的流速能使装置实现准静态平面均匀流场，适合培养组织工程皮肤。但是，装置中组织与环境间的相互作用非常复杂，并且营养传递方式多样，包括对流、扩散和渗透等，为了弄清这些复杂的关系，本研究将采用非结构动力学模型结合实验研究对装置中组织工程皮肤的生长代谢进行数学建模：依据实验数据，应用Matlab软件对模型参数进行非线性规划，获得全局收敛的最优参数估计值，通过比较模型预测值与实测值的拟合情况及实验评估工程皮肤的培养效果，最终使模型能真实地反映流场、营养传递和底物等对支架内细胞生长代谢影响的内在规律。为灌注培养控制策略的制定、培养基流加方案的预估、工程皮肤的收获时间及培养过程的优化控制提供理论依据，并为下一步扩大化生产及其它工程组织的数学建模提供参考。

组织工程皮肤体外灌注培养不能取得令人满意的效果，原因之一是对其体外生长代谢状况知之甚少，不能针对其生长特性及生长要求合理控制并优化培养条件。本研究在我们前期建立的灌注培养技术平台上，采用数学模型分析和实验研究相结合来进一步探明准静态平面均匀流场培养条件下组织工程皮肤生长代谢的动力学规律。首先摸索并改良了培养基配方和复方壳多糖基质凝胶；其次，摸索了表真皮细胞接种浓度和比例，结果表明：当细胞接种浓度为 Kc：Fb = 16x104/孔:4x104/ml，和32x104/孔:8x104/ml时，采用低葡萄糖培养基培养14天的表真皮形态、结合紧密度、 细胞量及表皮层数最优。再次，我们通过检测人游离皮片的培养效果进一步验证了装置的可靠性，并得出提高灌注频次（每次灌注 4min 间停 2min）可延长游离人皮组织的体外存活时间。