Collagen scaffolds reinforced with biomimetic composite nano-sized carbonate-substituted hydroxyapatite crystals and shaped by rapid prototyping to contain internal microchannels
Collagen scaffolds reinforced with biomimetic composite nano-sized carbonate-substituted hydroxyapatite crystals and shaped by rapid prototyping to contain internal microchannels
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DOI：
10.1089/ten.2006.12.2479
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发表时间：
2006-09-01
影响因子：
--
通讯作者：
Czernuszka, Jan T.
中科院分区：
文献类型：
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作者：
Sachlos, Eleftherios;Gotora, Duce;Czernuszka, Jan T.
下一代组织工程支架将被制造成容纳血管和营养通道，以支持支架内部深处的细胞存活。为此，我们已经开发出一种方法，采用微通道，允许富含营养的介质通过胶原蛋白为基础的支架流动。支架基质包括在胶原纤维中内部沉淀的纳米尺寸的碳酸盐取代的羟基磷灰石（HA）晶体。因此，支架模仿了骨骼中发现的许多特征。使用仿生沉淀技术，由此胶原膜分离钙和磷酸盐溶液的储库。从相反方向扩散的钙离子和磷酸根离子的碰撞导致胶原膜内的矿物质沉淀。透射电子显微镜分析显示，矿物晶体的尺寸约为180 × 80 × 20 nm，表明晶体存在于微纤维间隙中。电子衍射表明，矿物是在HA相，和红外光谱证实A型碳酸盐取代。然后使用胶原- HA膜制备三维（3D）支架：将膜切碎并混合在水基胶原分散体中，并使用临界点干燥方法进行处理。在混合复合组分之前将分散体的pH调节至5.0保存了纳米尺寸的碳酸盐取代的HA晶体。支架内部的分支和互连微通道是用3D蜡打印机制造的牺牲模具制成的。3D蜡打印机已经过修改，可以用生物相容性材料打印模具。胶原蛋白-HA支架内适当尺寸的微通道使我们更接近于满足支架内深层生活的成骨细胞的质量运输要求。
The next generation of tissue engineering scaffolds will be made to accommodate blood vessels and nutrient channels to support cell survival deep in the interior of the scaffolds. To this end, we have developed a method that incorporates microchannels to permit the flow of nutrient-rich media through collagen-based scaffolds. The scaffold matrix comprises nano-sized carbonate-substituted hydroxyapatite (HA) crystals internally precipitated in collagen fibers. The scaffold therefore mimics many of the features found in bone. A biomimetic precipitation technique is used whereby a collagen membrane separates reservoirs of calcium and phosphate solutions. The collision of calcium and phosphate ions diffusing from opposite directions results in the precipitation of mineral within the collagen membrane. Transmission electron microscopy analysis showed the dimension of the mineral crystals to be approximately 180x80x20 nm, indicating that the crystals reside in the intermicrofibril gaps. Electron diffraction indicated that the mineral was in the HA phase, and infrared spectroscopy confirmed type A carbonate substitution. The collagen- HA membrane is then used to make 3-dimensional ( 3D) scaffolds: the membrane is shredded and mixed in an aqueous-based collagen dispersion and processed using the critical point drying method. Adjusting the pH of the dispersion to 5.0 before mixing the composite component preserved the nano-sized carbonate-substituted HA crystals. Branching and interconnecting microchannels in the interior of the scaffolds are made with a sacrificial mold manufactured by using a 3D wax printer. The 3D wax printer has been modified to print the mold from biocompatible materials. Appropriately sized microchannels within collagen-HA scaffolds brings us closer to fulfilling the mass transport requirements for osteogenic cells living deep within the scaffold.