Salgado Christiane Laranjo, Teixeira Beatriz Isabel Brites, Monteiro Fernando Jorge Mendes
i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.
INEB-Instituto Nacional de Engenharia Biomédica, Universidade do Porto, Porto, Portugal.
Front Bioeng Biotechnol. 2019 Sep 6;7:206. doi: 10.3389/fbioe.2019.00206. eCollection 2019.
In guided bone tissue engineering, successful ingrowth of MSCs depends primarily on the nature of the scaffold. It is well-known that only seconds after implantation, biomaterials are coated by a layer of adsorbed proteins/peptides which modulates the subsequent cell/scaffold interactions, especially at early times after implantation. In this work, nanohydroxyapatite and collagen based composite materials (Coll/nanoHA) were modified with phosphorylated amino acid (O-phospho-L-serine-OPS) to mimic bone tissue, and induce cell differentiation. The choice for this phosphorylated amino acid is due to the fact that osteopontin is a serine-rich glycol-phosphoprotein and has been associated to the early stages of bone formation, and regeneration. Several concentrations of OPS were added to the Coll/nanoHA scaffold and physico-chemical, mechanical, and cell behavior were evaluated. Afterwards, the composite scaffold with stronger mechanical and best cellular behavior was tested , with or without previous culture of human MSC's (bone tissue engineering). The OPS signaling of the biocomposite scaffolds showed similar cellular adhesion and proliferation, but higher ALP enzyme activity (HBMSC). bone ectopic formation studies allowed for a thorough evaluation of the materials for MSC's osteogenic differentiation. The OPS-scaffolds results showed that the material could modulated mesenchymal cells behavior in favor of osteogenic differentiation into late osteoblasts that gave raised to their ECM with human bone proteins (osteopontin) and calcium deposits. Finally, OPS-modified scaffolds enhanced cell survival, engraftment, migration, and spatial distribution within the 3D matrix that could be used as a cell-loaded scaffold for tissue engineering applications and accelerate bone regeneration processes.
在引导性骨组织工程中，间充质干细胞的成功向内生长主要取决于支架的性质。众所周知，植入后仅数秒，生物材料就会被一层吸附的蛋白质/肽所覆盖，这会调节随后的细胞/支架相互作用，尤其是在植入后的早期阶段。在这项工作中，基于纳米羟基磷灰石和胶原蛋白的复合材料（Coll/nanoHA）用磷酸化氨基酸（O-磷酸-L-丝氨酸，OPS）进行修饰，以模拟骨组织并诱导细胞分化。选择这种磷酸化氨基酸是因为骨桥蛋白是一种富含丝氨酸的糖磷蛋白，并且与骨形成和再生的早期阶段有关。将几种浓度的OPS添加到Coll/nanoHA支架中，并评估其物理化学性质、力学性能和细胞行为。之后，对具有更强力学性能和最佳细胞行为的复合支架进行了测试，无论是否预先培养人骨髓间充质干细胞（用于骨组织工程）。生物复合支架的OPS信号显示出相似的细胞粘附和增殖，但碱性磷酸酶（ALP）活性更高（人骨髓间充质干细胞）。骨异位形成研究能够全面评估材料对骨髓间充质干细胞成骨分化的作用。OPS支架的结果表明，该材料可以调节间充质细胞的行为，有利于其向晚期成骨细胞进行成骨分化，晚期成骨细胞会产生含有人类骨蛋白（骨桥蛋白）和钙沉积的细胞外基质。最后，OPS修饰的支架提高了细胞在三维基质中的存活率、植入率、迁移率和空间分布，可作为组织工程应用中负载细胞的支架，并加速骨再生过程。
