Fabrication of porous beta-tricalcium phosphate with microchannel and customized geometry based on gel-casting and rapid prototyping

Abstract

The tissue engineering scaffolds with three-dimensional porous structure are regarded to be beneficial to facilitate a sufficient supply of nutrients and enable cell ingrowth in bone reconstruction. However, the pores in scaffolds tend to be blocked by the cell ingrowth and result in a restraint of nutrient supply in the further side of the scaffold. An indirect approach of combining the rapid prototyping and gel-casting technique is introduced in this study to fabricate beta-tricalcium phosphate (beta-TCP) scaffolds which not only have interconnected porous structure, but also have a microchannel network inside. The scaffold was designed with customized geometry that matches the defect area, and a double-scale (micropores-microchannel) porous structure inside that is beneficial for cell ingrowth. The scaffolds fabricated have an open, uniform, and interconnected porous architecture with a pore size of 200-400 microm, and posses an internal channel network with a diameter of 600 microm. The porosity was controllable. The compressive yield strength was 4.5 MPa with a porosity of 70 per cent. X-ray diffraction analysis shows that these fabrication processes do not change the crystal structure and chemical composition of beta-TCP. With this technique, it was also possible to fabricate porous scaffolds with desired pore size, porosity, and microchannel, as well as customized geometries by other bioceramics.

Preparation and Characterization of Poly(vinyl alcohol)-chondroitin Sulphate Hydrogel as Scaffolds for Articular Cartilage Regeneration

“…The apparent density of hydrogel scaffolds was studied by soaking them overnight in distilled water at room temperature. The apparent density of the scaffolds was calculated from the following equation (see [21]):…”

Hierarchical structures of β-TCP/45S5 bioglass hybrid scaffolds prepared by gelcasting

“…Although, β-TCP and HA have both biocompatible and osteoconductive properties, the β-TCP is far more reabsorbable, indicating that it may interact with the hard tissues. This important feature makes β-TCP an interesting material for the manufacture of temporary scaffold that degrades with advancing bone growth, thus allowing bone to regenerate (Hesaraki et al, 2009;Li et al, 2011;Liang et al, 2010;Reid et al, 2005). Although, β-TCP presents two main disadvantages: the absence of osteostimulation properties and its brittleness under loading, which is a common feature in all bioceramic materials (Debusscher et al, 2009).…”

大尺寸关节支架的3d打印及应用

“…而关节支架的曲面最宽尺寸以及 PLA 固定桩直径、固定桩间距等尺寸减小, 则是因为 陶瓷素坯的内部水分和有机物经历高温烧结时消失, 陶瓷颗粒向中间聚集、填充所造成的. 然而陶瓷 颗粒间并非完全紧密结合, 而是形成大量的间隙以助于材料降解 [16,17] .…”

“…本实验室利用可光敏交联的基团 (如 methacryl -甲基丙烯酸酰, diacrylate -二丙烯酸盐) 对 PEG 进行改性, 以光引发剂和激光照射下使之交联形成 水凝胶的原理, 建立了水凝胶的光固化成形工艺方法 [8] ; 并形成了以光固化成型模具与凝胶灌注工艺 结合, 间接成型复杂结构陶瓷支架的技术及 PLA/陶瓷复合材料支架 [1,15∼18] . 前期的研究也形成了基 于影像学数据构建组织缺损区域的生理结构和手术导航模板技术 [1,8,15,16,19] , 本文在此基础上进一步 研究大尺寸关节支架的仿生定制化设计方法, 并以诱导组织生长为导向, 选择 PEG 凝胶、β-TCP 生 物陶瓷、PLA 等生物材料开发多材料 3D 打印成型方法和可行性的植入手术方法, 为大面积骨/软骨 缺损提供新的治疗方案. 2.1 倍 [19,20] .…”