Cell‐based tissue engineering strategies have been widely established. However, the contributions of the transplanted cells within the tissue‐engineered scaffolds to the process of tissue regeneration remain poorly understood. Near‐infrared (NIR) fluorescence imaging systems have great potential to non‐invasively monitor the transplanted cell‐based tissue constructs. In this study, labeling mesenchymal stem cells (MSCs) using a lipophilic pentamethine indocyanine (CTNF127, emission at 700 nm) as a NIR fluorophore was optimized, and the CTNF127‐labeled MSCs (NIR‐MSCs) were printed embedding in gelatin methacryloyl bioink. The NIR‐MSCs‐loaded bioink showed excellent printability. In addition, NIR‐MSCs in the 3D constructs showed high cell viability and signal stability for an extended period in vitro. Finally, we were able to non‐invasively monitor the NIR‐MSCs in constructs after implantation in a rat calvarial bone defect model, and the transplanted cells contributed to tissue formation without specific staining. This NIR‐based imaging system for non‐invasive cell monitoring in vivo could play an active role in validating the cell fate in cell‐based tissue engineering applications.

中文翻译：

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使用近红外荧光成像对 3D 生物打印结构中移植的干细胞进行无创体内监测

基于细胞的组织工程策略已被广泛建立。然而，组织工程支架内移植细胞对组织再生过程的贡献仍知之甚少。近红外（NIR）荧光成像系统在非侵入性监测移植的细胞组织结构方面具有巨大潜力。在本研究中，使用亲脂性五次甲基吲哚菁（CTNF127，发射波长为 700 nm）作为 NIR 荧光团对间充质干细胞（MSC）进行了优化，并将 CTNF127 标记的 MSC（NIR-MSC）打印嵌入明胶甲基丙烯酰生物墨水中。负载 NIR-MSCs 的生物墨水表现出优异的印刷适性。此外，3D 构建体中的 NIR-MSC 在体外表现出长时间的高细胞活力和信号稳定性。最后，我们能够在植入大鼠颅骨骨缺损模型后，对构建体中的 NIR-MSC 进行非侵入性监测，并且移植的细胞无需特定染色即可促进组织形成。这种用于体内非侵入性细胞监测的基于近红外的成像系统可以在验证基于细胞的组织工程应用中的细胞命运方面发挥积极作用。