The stiffness of a hydrogel has a significant role on the mechanical stability of a scaffold. However, the stiffness of pure hydrogels can be tuned only within a limited range. Herein, it is hypothesized that the range of hydrogel stiffness can be greatly increased by the addition of calcium phosphate particles and that such composites promote the osteogenic differentiation of human mesenchymal stem cells (hMSCs). Beta‐tricalcium phosphate (β‐TCP) particles are incorporated at concentrations of 0.5 and 5 mg mL⁻¹ into various agarose and agarose–collagen blends. These composites are characterized with respect to stiffness, viscosity, degradation, cell morphology, viability, and osteogenesis. The osteogenic hMSCs in less stiff composites with 0.5 mg mL⁻¹ β‐TCP show the highest alkaline phosphatase expression compared to blends without β‐TCP and stiffer composites with 5 mg mL⁻¹ β‐TCP. Quantitative polymerase chain reaction also shows higher expression of ALP, RUNX2, and collagen I by hMSCs in less stiff composites with 0.5 mg mL⁻¹ β‐TCP compared to blends without β‐TCP and stiffer composite blends. It is concluded that by addition of calcium phosphate to specific hydrogels the stiffness can be tuned in a desired range and thus the osteogenic differentiation of embedded hMSCs can be better controlled and adjusted compared to pure hydrogels.

中文翻译：

---

在基于水凝胶的复合材料中添加磷酸钙颗粒对间质基质细胞向成骨的刚度和分化的影响

水凝胶的刚度对支架的机械稳定性具有重要作用。但是，纯水凝胶的刚度只能在有限的范围内进行调整。在本文中，假设通过添加磷酸钙颗粒可以大大增加水凝胶刚度的范围，并且这种复合物促进人间充质干细胞（hMSC）的成骨分化。β-磷酸三钙（β-TCP）颗粒以0.5和5 mg mL ^-1的浓度掺入各种琼脂糖和琼脂糖-胶原蛋白混合物中。这些复合材料的特征在于硬度，粘度，降解，细胞形态，生存力和成骨性。具有0.5 mg mL ^-1的硬度较低的复合物中的成骨hMSCβ-TCP相比显示出没有β-TCP共混物和复合材料更硬用5mg毫升最高碱性磷酸酶表达^-1 β-TCP。定量聚合酶链反应也显示ALP，RUNX2的表达更高，和I型胶原通过在的hMSCs不太硬的复合材料用0.5mg毫升^-1 β-TCP相比，没有β-TCP共混物和复合材料更硬的共混物。结论是，通过将磷酸钙添加到特定的水凝胶中，可以将硬度调节到所需的范围，因此与纯水凝胶相比，可以更好地控制和调节嵌入式hMSC的成骨分化。