Taguchi T, Kishida A, Akashi M
Department of Applied Chemistry and Chemical Engineering, Faculty of Engineering, Kagoshima University, Korimoto, Japan.
J Biomater Sci Polym Ed. 1999;10(3):331-9. doi: 10.1163/156856299x00397.
In our previous study, we reported a novel method of apatite formation on/in a three-dimensional hydrogel matrix. Using this method, bone-like apatite could be formed on/in the hydrogel matrix under normal conditions in vitro. A poly(vinyl alcohol) (PVA) gel was used as a model matrix. The method consists of two steps: first, water is transformed in a PVA gel with a CaCl2/Tris-HCl aqueous solution (pH 7.4) and second, the gel is soaked in a Na2HPO4 aqueous solution. In the present study, we report a detailed study of the effects of the swelling ratios of PVA gels on apatite formation. Cross-sectional observations and gravimetric measurements of PVA gels with various swelling ratios were done. The amount of apatite formed on/in PVA gels increased almost linearly with an increase in the reaction cycles. The rates of apatite formation on/in PVA gels largely depended on the swelling ratios, which were approximately 0.48, 0.61, 1.28, and 1.55 mg per cycle for swelling ratios of 4.1, 10.4, 16.8, and 30.1, respectively. The apatite content in PVA-apatite composites that was obtained by this method also increased with an increase of the reaction cycles. After six reaction cycles, a PVA gel with a high swelling ratio contains approximately 70 wt% of formed apatite in the composite. On the other hand, a gel with a low swelling ratio contains about 15 wt% of formed apatite in the composite. Cross-sectional views of the PVA gels after each cycle showed that apatite crystals were formed, not only on the surface of the gel but also within it after fifteen reaction cycles. The hydrogel-apatite composites that were obtained using an alternative soaking process will be useful as not only bone substitute materials but also as soft tissue adhesive materials.
在我们之前的研究中，我们报道了一种在三维水凝胶基质上/内形成磷灰石的新方法。使用这种方法，在体外正常条件下，骨样磷灰石可在水凝胶基质上/内形成。聚（乙烯醇）（PVA）凝胶用作模型基质。该方法包括两个步骤：首先，用CaCl2/Tris-HCl水溶液（pH 7.4）将水转化到PVA凝胶中，其次，将凝胶浸泡在Na2HPO4水溶液中。在本研究中，我们报告了PVA凝胶溶胀率对磷灰石形成影响的详细研究。对具有不同溶胀率的PVA凝胶进行了横截面观察和重量测量。在PVA凝胶上/内形成的磷灰石量几乎随反应循环次数的增加呈线性增加。PVA凝胶上/内磷灰石的形成速率很大程度上取决于溶胀率，对于溶胀率分别为4.1、10.4、16.8和30.1的情况，每循环形成的磷灰石量分别约为0.48、0.61、1.28和1.55 mg。通过该方法获得的PVA-磷灰石复合材料中的磷灰石含量也随反应循环次数的增加而增加。经过六个反应循环后，具有高溶胀率的PVA凝胶在复合材料中含有约70 wt%的形成的磷灰石。另一方面，具有低溶胀率的凝胶在复合材料中含有约15 wt%的形成的磷灰石。每个循环后PVA凝胶的横截面视图显示，在十五个反应循环后，不仅在凝胶表面而且在凝胶内部都形成了磷灰石晶体。使用替代浸泡工艺获得的水凝胶-磷灰石复合材料不仅可用作骨替代材料，还可用作软组织粘附材料。
