High-Resolution 1.5-Tesla Magnetic Resonance Imaging for Tissue-Engineered Constructs: A Noninvasive Tool to Assess Three-Dimensional Scaffold Architecture and Cell Seeding
High-Resolution 1.5-Tesla Magnetic Resonance Imaging for Tissue-Engineered Constructs: A Noninvasive Tool to Assess Three-Dimensional Scaffold Architecture and Cell Seeding
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DOI：
10.1089/ten.tec.2009.0015
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发表时间：
2010-04-01
影响因子：
3
通讯作者：
Gazeau, Florence
中科院分区：
文献类型：
--
作者：
Poirier-Quinot, Marie;Frasca, Guillaume;Gazeau, Florence
组织工程支架由具有不同结构的生物相容性聚合物制成，允许细胞播种、生长和分化。在植入前后研究组织工程构建体需要无创成像方法。在这里，我们展示了在临床1.5 t设备上进行的高分辨率磁共振成像（MRI）是评估多孔支架三维结构和验证细胞播种程序的可靠技术。在对支架成像时，使用高温超导检测线圈实现30 x 30 x 30 mm(3)的分辨率。利用天然来源的多糖制备了三种具有可调结构的结构，并对其作为间充质干细胞（MSC）培养的支架进行了评价。为了监测细胞的播种情况，利用柠檬酸阴离子包被氧化铁纳米颗粒的简单孵育30分钟，对MSCs进行磁标记。单细胞磁泳定量铁摄取，标记后7天检测细胞增殖。利用MRI评估支架的三维微观结构，根据支架的制备工艺显示片状或球状多孔组织。将不同铁负荷（每个细胞5、12和31 pg铁）的MSCs以低密度（132个细胞/mm(3)）植入支架上，在3D梯度回波MR图像上根据相位畸变和强烈低信号区域进行检测，其大小随着细胞铁负荷和回波时间的增加而增加。支架中的总体信号损失与种子细胞的数量及其铁负荷相关。根据支架结构的不同，观察到不同的细胞组织。在小鼠皮下植入后，通过观察信号和相位异质性以及测量整体信号损失，可以在体内区分植入标记细胞的支架与未植入标记细胞的支架。高分辨率1.5 t MRI结合高效的细胞内造影剂，有望在体内植入前后实现组织工程构建体的无创3D可视化。
Tissue-engineered scaffolds are made of biocompatible polymers with various structures, allowing cell seeding, growth, and differentiation. Noninvasive imaging methods are needed to study tissue-engineered constructs before and after implantation. Here, we show that high-resolution magnetic resonance imaging (MRI) performed on a clinical 1.5-T device is a reliable technique to assess three-dimensional structures of porous scaffolds and to validate cell-seeding procedures. A high-temperature superconducting detection coil was used to achieve a resolution of 30 x 30 x 30 mm(3) when imaging the scaffolds. Three types of structures with tuneable architectures were prepared from naturally derived polysaccharides and evaluated as scaffolds for mesenchymal stem cell (MSC) culture. To monitor cell seeding, MSCs were magnetically labeled using simple incubation with anionic citrate-coated iron-oxide nanoparticles for 30 min. Iron uptake was quantified using single-cell magnetophoresis, and cell proliferation was checked for 7 days after labeling. Three-dimensional (3D) microstructures of scaffolds were assessed using MRI, revealing lamellar or globular porous organization according to the scaffold preparation process. MSCs with different iron load (5, 12 and 31 pg of iron per cell) were seeded on scaffolds at low density (132 cells/mm(3)) and detected on 3D gradient-echo MR images according to phase distortions and areas of intensely low signal, whose size increased with cell iron load and echo time. Overall signal loss in the scaffold correlated with the number of seeded cells and their iron load. Different organizations of cells were observed depending on the scaffold architecture. After subcutaneous implantation in mice, scaffolds seeded with labeled cells could be distinguished in vivo from scaffold with nonlabeled cells by observation of signal and phase heterogeneities and by measuring the global signal loss. High-resolution 1.5-T MRI combined with efficient intracellular contrast agents shows promise for noninvasive 3D visualization of tissue-engineered constructs before and after in vivo implantation.