We report an osteoconducting magnetic 3D scaffold using Fe²⁺ doped nano-hydroxyapatite-Alginate-Gelatin (AGHFe1) for Magnetic Resonance Imaging based non-invasive monitoring of bone tissue regeneration. In rat cranial defect model, the scaffold facilitated non-invasive monitoring of cell migration, inflammatory response and matrix deposition by unique changes in transverse relaxation time (T2). Cell infiltration resulted in a considerable increase in T2 from ~37 to ~62 ms, which gradually returned to that of native bone (~23 ms) by 90 days. We used this method to compare in vivo performance of scaffold with bone-morphogenic protein-2 (AGHFe2) or faster degrading (AGHFe3). MRI and histological analysis over 90 days showed non-uniform bone formation in AGHFe1 with ∆T2 (T2_{Native bone} – T2 _{Regenerated bone}) ~13 ms, whereas, AGHFe2 and AGHFe3 showed ∆T2 ~ 09 and 05 ms respectively, suggesting better bone formation in AGHFe3. Thus, we show that MR-contrast enabled scaffold can help better assessment of bone-regeneration non-invasively.

我们报告了使用Fe ²⁺掺杂的纳米羟基磷灰石-藻酸盐-明胶（AGHFe1）的骨传导磁性3D支架，用于基于磁共振成像的骨组织再生的无创监测。在大鼠颅骨缺损模型中，支架通过横向弛豫时间（T2）的独特变化，促进了细胞迁移，炎症反应和基质沉积的无创监测。细胞浸润导致T2从〜37 ms显着增加到〜62 ms，并在90天后逐渐恢复为天然骨（〜23 ms）。我们使用这种方法来比较具有骨形态发生蛋白2（AGHFe2）或更快降解（AGHFe3）的支架的体内性能。超过90天的MRI和组织学分析显示，AGHFe1的骨形成不均匀，伴有ΔT2（T2_天然骨– T2_再生骨）〜13 ms，而AGHFe2和AGHFe3分别显示∆T2〜09和05 ms，表明AGHFe3中更好的骨形成。因此，我们表明启用MR造影剂的支架可以帮助非侵入性更好地评估骨再生。