Department of Biomaterials, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi Higashi-ku, Fukuoka 812-8582, Japan.
Department of Biomaterials, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi Higashi-ku, Fukuoka 812-8582, Japan.
Mater Sci Eng C Mater Biol Appl. 2020 Jun;111:110848. doi: 10.1016/j.msec.2020.110848. Epub 2020 Mar 13.
The pore architecture of scaffolds is a critical factor for angiogenesis and bone regeneration. Although the effects of scaffold macropore size have been investigated, most scaffolds feature macropores with poor uniformity and interconnectivity, and other parameters (e.g., microporosity, chemical composition, and strut thickness) differ among scaffolds. To clarify the threshold of effective macropore size, we fabricated honeycomb scaffolds (HCSs) with distinct macropore (i.e., channel) sizes (~100, ~200, and ~300 μm). The HCSs were composed of AB-type carbonate apatite with ~8.5% carbonate ions, i.e., the same composition as human bone mineral. Their honeycomb architecture displayed uniformly sized and orderly arranged channels with extremely high interconnectivity, and all the HCSs displayed ~100-μm-thick struts and 0.06 cm g of micropore volume. The compressive strengths of HCSs with ~100-, ~200-, and ~300-μm channels were higher than those of reported scaffolds, and decreased with increasing channel size: 62 ± 6, 55 ± 9, and 43 ± 8 MPa, respectively. At four weeks after implantation in rabbit femur bone defects, new bone and blood vessels were formed in all the channels of these HCSs. Notably, the ~300-μm channels were extensively occupied by new bone. We demonstrated that high interconnectivity and uniformity of channels can decrease the threshold of effective macropore size, enabling the scaffolds to maintain high mechanical properties and osteogenic ability and serve as implants for weight-bearing areas.
支架的孔结构是血管生成和骨再生的关键因素。尽管已经研究了支架大孔尺寸的影响，但大多数支架的大孔尺寸均匀性和连通性较差，并且其他参数（例如微孔率、化学成分和支柱厚度）在支架之间存在差异。为了阐明有效大孔尺寸的阈值，我们制造了具有不同大孔（即通道）尺寸（100、200 和300μm）的蜂窝状支架（HCS）。HCS 由 AB 型碳酸磷灰石组成，含有约 8.5%的碳酸根离子，即与人体骨矿物质相同的成分。它们的蜂窝状结构具有均匀尺寸和有序排列的通道，具有极高的连通性，所有 HCS 均具有100-μm 厚的支柱和 0.06cm^3/g 的微孔体积。具有100、200 和300μm 通道的 HCS 的抗压强度高于报道的支架，并且随着通道尺寸的增加而降低：分别为 62±6、55±9 和 43±8MPa。在兔股骨骨缺损中植入 4 周后，在这些 HCS 的所有通道中均形成了新骨和血管。值得注意的是，300μm 的通道被大量新骨占据。我们证明了通道的高连通性和均匀性可以降低有效大孔尺寸的阈值，使支架能够保持较高的机械性能和成骨能力，并用作承重区域的植入物。
