A variety of gadolinium (Gd) based nanoparticles (NPs) were synthesized due to the unique magnetic properties of Gd-containing rare earth compounds and the particularity of micro/nano-materials, which were then incorporated into hydroxyapatite (HA) to obtain inorganic-organic composite materials. Then, HA/Gd NPs containing slow-release transforming growth factor (TGF-β1) were harvested. Adipose-derived stem cells (ADSCs) were extracted from the adipose tissue of a four-month-old New Zealand white rabbit. HA/Gd NPs were attached to absorbable gelatin sponge to obtain HA/Gd NPs/gelatin sponge composite scaffold. In addition, the third generation ADSCs were taken and cultured in the composite scaffold, so that ADSCs-HA/Gd bio-nanocomposites were obtained. The in vitro culture test of osteoblast MC3T3-E1 showed that Gd-containing NPs had good biocompatibility. The prepared HA/Gd NPs loaded with TGF-β1 were spherical, with an average particle size of (9.16 ± 3.16) μm. The NPs were easy to aggregate and adherent. Enzyme-linked immunosorbent assay (ELISA) test results showed that TGF-β1 in NPs was sustained and released continuously for 29 days. HA/Gd NPs/gelatin sponge composite scaffold combined with ADSCs were co-cultured for three days, and the electron microscope showed that the HA/Gd NPs were dispersed, and the cells could adhere and grow well. Then, animal models of rabbit knee articular cartilage defects were established and were rolled into three groups (ADSCs-HA/Gd nano group, HA/Gd nano scaffold group, and blank control). The repair area of the rabbit knee of ADSCs-HA/Gd nano group was smooth and flat, the scaffold was absorbed, the toluidine blue stain was positive, and the type II collagen immunohistochemical stain was positive. In general, ADSCs-HA/Gd nanomaterials were helpful for chondrogenic cell differentiation and had certain adoption prospects in the field of tissue engineering to repair cartilage defects.

中文翻译：

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含钆生物纳米复合材料修复兔膝关节软骨下缺损及关节软骨。

由于含钆稀土化合物独特的磁性和微/纳米材料的特殊性，合成了多种钆（Gd）基纳米粒子（NPs），然后将其掺入羟基磷灰石（HA）中以获得无机-有机复合材料。然后，收获含有缓释转化生长因子 (TGF-β1) 的 HA/Gd NPs。从一只四个月大的新西兰白兔的脂肪组织中提取脂肪干细胞 (ADSCs)。HA/Gd NPs 附着在可吸收的明胶海绵上，得到 HA/Gd NPs/明胶海绵复合支架。此外，取第三代ADSCs在复合支架中培养，得到ADSCs-HA/Gd生物纳米复合材料。成骨细胞MC3T3-E1体外培养试验表明，含Gd纳米颗粒具有良好的生物相容性。制备的载有 TGF-β1 的 HA/Gd NPs 呈球形，平均粒径为 (9.16 ± 3.16) μm。NPs 易于聚集和粘附。酶联免疫吸附试验 (ELISA) 测试结果表明，NPs 中的 TGF-β1 持续释放持续 29 天。HA/Gd NPs/明胶海绵复合支架结合ADSCs共培养3天，电镜下显示HA/Gd NPs呈分散状态，细胞贴壁生长良好。然后建立兔膝关节软骨缺损动物模型，分为三组（ADSCs-HA/Gd纳米组、HA/Gd纳米支架组和空白对照）。ADSCs-HA/Gd纳米组兔膝关节修复区光滑平整，支架吸收，甲苯胺蓝染色阳性，II型胶原免疫组化染色阳性。总的来说，ADSCs-HA/Gd纳米材料有助于软骨细胞分化，在组织工程修复软骨缺损领域具有一定的应用前景。