Ectopic bone formation in mice is the gold standard for evaluation of osteogenic constructs. By regular procedures, usually only 4 constructs can be accommodated per mouse, limiting screening power. Combinatorial cassettes (combi-cassettes) hold up to 19 small, uniform constructs from the time of surgery, through time in vivo, and subsequent evaluation. Two types of bone tissue engineering constructs were tested in the combi-cassettes: i) a cell-scaffold construct containing primary human bone marrow stromal cells with hydroxyapatite/tricalcium phosphate particles (hBMSCs + HA/TCP) and ii) a growth factor-scaffold construct containing bone morphogenetic protein 2 in a gelatin sponge (BMP2+GS). Measurements of bone formation by histology, bone formation by X-ray microcomputed tomography (μCT) and gene expression by quantitative polymerase chain reaction (qPCR) showed that constructs in combi-cassettes were similar to those created by regular procedures. Combi-cassettes afford placement of multiple replicates of multiple formulations into the same animal, which enables, for the first time, rigorous statistical assessment of: 1) the variability for a given formulation within an animal (intra-animal variability), 2) differences between different tissue-engineered formulations within the same animal and 3) the variability for a given formulation in different animals (inter-animal variability). Combi-cassettes enable a more high-throughput, systematic approach to in vivo studies of tissue engineering constructs.

小鼠异位骨形成是评估成骨结构的金标准。通过常规程序，每只小鼠通常只能容纳4个构建体，从而限制了筛选能力。从手术开始到体内，组合盒（组合盒）最多可容纳19个均匀的小结构，然后进行后续评估。在组合式磁带中测试了两种类型的骨组织工程构建体：i）包含人原代骨髓基质细胞和羟基磷灰石/磷酸三钙颗粒（hBMSCs + HA / TCP）的细胞支架构建体； ii）生长因子支架在明胶海绵（BMP2 + GS）中含有骨形态发生蛋白2的构建体。通过组织学测量骨形成，通过X射线计算机断层扫描（μCT）进行的骨骼形成和通过定量聚合酶链反应（qPCR）进行的基因表达表明，组合式磁带盒中的构建体与常规程序中的相似。组合式磁带盒可将多种制剂的多个复制品放置到同一只动物中，这首次实现了以下方面的严格统计评估：1）给定制剂在动物体内的变异性（动物内变异性），2）差异在同一只动物的不同组织工程制剂之间进行比较；以及3）在不同动物中给定制剂的变异性（动物间变异性）。组合式磁带盒为组织工程构建体的体内研究提供了更高通量的系统方法。