基于Micro-CT不同多孔结构陶瓷支架的建模及其贯通性与液流分布分析

doi:10.15541/jim20140204

无机材料学报 ›› 2015, Vol. 30 ›› Issue (1): 71-76.DOI: 10.15541/jim20140204 CSTR: 32189.14.10.15541/jim20140204

基于Micro-CT不同多孔结构陶瓷支架的建模及其贯通性与液流分布分析

罗品风^1,2, 智伟¹, 张静微¹, 匙峰¹, 段可^1,2, 汪建新¹, 鲁雄¹, 翁杰¹

(1. 西南交通大学, 材料先进技术教育部重点实验室, 材料科学与工程学院, 成都610031; 2. 淮阴工学院, 江苏省介入医疗器械研究重点实验室, 淮阴 223003)

收稿日期:2014-04-16 修回日期:2014-06-03 出版日期:2015-01-20 网络出版日期:2014-12-29
作者简介:罗品风(1986–), 男, 硕士研究生. E-mail: hack1024@163.com
基金资助:
国家重点基础研究发展计划(973计划, 2012CB933600);国家自然科学基金(51172188);四川省科技支撑计划(2010FZ0048)

Interconnectivity of Bioceramic Scaffolds with Different Porous Structures and Their Fluid Velocity Distribution Analyzed by Micro-CT Computer Modeling

LUO Pin-Feng^1,2, ZHI Wei¹, ZHANG Jing-Wei¹, SHI Feng¹, DUAN Ke^1,2, WANG Jian-xin¹, LU Xiong¹, WENG Jie¹

(1. Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China; 2. Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology Huaiyin 223003, China)

Received:2014-04-16 Revised:2014-06-03 Published:2015-01-20 Online:2014-12-29
About author:LUO Pin-Feng. E-mail: hack1024@163.com
Supported by:
National Basic Research Program of China (973 Program, 2012CB933600);National Nature Science Foundation of China (51172188);Science and Technology Pillar Project of Sichuan (2010FZ0048)

摘要/Abstract

摘要：

贯通性是骨组织工程支架的重要参数, 决定包含蛋白和细胞的体液渗入和组织生长。本研究采用Micro-CT技术对三种不同工艺(球粒堆积、蜡球造孔、纤维堆积)构建的羟基磷灰石多孔支架进行断层扫描, 并从三方面研究支架的贯通性: (1)通过影像重建定量分析支架孔隙的三维贯通结构; (2)统计分析比较三种支架在贯流方向上的孔隙率变化; (3)有限元模拟支架的内部液流分布情况。结果表明, 球粒堆积支架与蜡球造孔支架孔隙率分布较均匀, 而纤维堆积支架孔隙分布较杂乱。液流模拟(流速分布)发现, 球粒堆积支架与蜡球造孔支架中液体流动均匀, 但是蜡球造孔支架孔壁近表面区域存在大量“漩涡流”, 不利于支架内细胞与液流之间的物质交换, 该结果有可能解释球粒堆积支架体内成骨性优于蜡球造孔支架的动物体内实验结果。

关键词: 组织工程支架, 结构图像重建, 孔隙贯通性, 计算机建模, 流速分布

Abstract:

Pore interconnectivity is a key parameter for bone tissue engineering scaffolds, which controls penetration of body fluid with proteins and cells, and tissue ingrowth. The present study investigated the porous characteristics of hydroxyapatite (HA) scaffolds prepared via three processes (HA sphere packing, wax sphere-leaching and HA fiber aggregation) by micro-computed tomography (μCT) from following three procedures: (1) modeling of the porous structure by image reconstruction; (2) analysis of porosity along longitudinal direction; and (3) simulation of fluid flow across the scaffold by finite element analysis (FEA). Image analyses revealed that, the scaffolds prepared by the above two methods featured relatively regular porosity distributions, whereas that by HA fiber aggregation had an irregular distribution. Fluid velocity distribution by FEA suggested that scaffolds prepared by HA sphere packing and wax sphere leaching readily allowed penetration of fluid due to their favorable pore interconnectivity. The fluid velocity vector distribution predicted that circular flows dominated near the pore wall in the scaffold prepared by wax sphere leaching. These circular flows may impede the material exchange between cells attached to the pore wall and the body fluid, which may illustrate that the inferior in vivo osteogenic activity of scaffolds prepared by wax sphere leaching when compared with those produced by HA sphere packing.

Key words: tissue engineering scaffolds, structure image reconstruction, interconnectivity, computer modeling, fluid velocity distribution

中图分类号:

R318

罗品风, 智伟, 张静微, 匙峰, 段可, 汪建新, 鲁雄, 翁杰. 基于Micro-CT不同多孔结构陶瓷支架的建模及其贯通性与液流分布分析[J]. 无机材料学报, 2015, 30(1): 71-76.

LUO Pin-Feng, ZHI Wei, ZHANG Jing-Wei, SHI Feng, DUAN Ke, WANG Jian-xin, LU Xiong, WENG Jie. Interconnectivity of Bioceramic Scaffolds with Different Porous Structures and Their Fluid Velocity Distribution Analyzed by Micro-CT Computer Modeling[J]. Journal of Inorganic Materials, 2015, 30(1): 71-76.

图/表 8

图1 Micro-CT断层图像边缘查找与填充处理: Micro-CT原始图像(a)和处理后图像(b)

Fig. 1 Illustration of edge detection and region filling in image analysis for scaffold structure reconstruction: original image by micro-CT (a), image after region filling (b)

图2 球粒堆积支架(a、b)、蜡球造孔支架(c、d)及纤维堆积支架(e、f)的三维重建模型(左)及其表面形貌(右)

Fig. 2 Reconstructed 3D models (left) revealing interconnected structures and surface morphologies (right) of scaffolds prepared by HA sphere packing (a, b), wax sphere leaching (c, d) and HA fiber aggregation (e, f)

图3 灰度反相处理断层图像分离支架内孔隙区域(a、 b); 反相处理后重建三维模型显示球粒堆积支架(c)、蜡球造孔支架(d)和纤维堆积支架(e)的内部孔隙结构

Fig. 3 Illustration of grayscale reverseprocessing for recog- nition of pore space in a scaffold (a, b), and visualization of pore spaces in scaffolds prepared by HA sphere packing (c), wax sphere leaching (d) and HA fiber aggregation (e)

表1 三种不同工艺制备的HA支架的平均宏孔孔隙率

Table 1 The average macro-porosity of three different HA scaffolds

Scaffold	Average macro-porosity
HA sphere packing	40.17%
Wax sphere leaching	62.23%
HA fiber aggregation	30.34%

图4 球粒堆积支架(a)、蜡球造孔支架(b)和纤维堆积支架(c)沿高度方向(轴向)的宏孔孔隙率变化趋势

Fig. 4 Variation along with the height direction (longitudinal) of scaffolds prepared by HA sphere packing (a), wax sphere leaching (b), and HA fiber aggregation (c)

图5 有限元模拟液流流经球粒堆积支架(a)蜡球造孔支架(b)的模型

Fig. 5 Schematic showing model used in finite-element simu lation of fluid flow across scaffolds prepared by HA sphere packing (a) and wax sphere leaching (b)

图6 有限元模拟液流流经球粒堆积支架(a)及蜡球造孔支架(b)孔隙的速度分布云图

Fig. 6 Velocity contours of fluid flow across scaffolds prepared by HA sphere packing (a) and wax sphere leaching (b) calculated by finite-element simulation

图7 有限元模拟血液流经球粒堆积支架(a)及蜡球造孔支架(b)孔隙的局部速度矢量图

Fig. 7 Velocity vector graphs of fluid flow across scaffolds prepared by HA sphere packing (a) and wax sphere leaching (b) calculated by finite-element simulation; (b: notice circular flows near pore wall)

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基于Micro-CT不同多孔结构陶瓷支架的建模及其贯通性与液流分布分析

Interconnectivity of Bioceramic Scaffolds with Different Porous Structures and Their Fluid Velocity Distribution Analyzed by Micro-CT Computer Modeling

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