Department of Biomedical Engineering, The University of Texas at Austin, 1 University Station, Austin, TX, USA.
Int J Nanomedicine. 2011;6:407-16. doi: 10.2147/IJN.S16354. Epub 2011 Feb 20.
Stem cells can differentiate into multiple cell types, and therefore can be used for cellular therapies, including tissue repair. However, the participation of stem cells in tissue repair and neovascularization is not well understood. Therefore, implementing a noninvasive, long-term imaging technique to track stem cells in vivo is needed to obtain a better understanding of the wound healing response. Generally, we are interested in developing an imaging approach to track mesenchymal stem cells (MSCs) in vivo after delivery via a polyethylene glycol modified fibrin matrix (PEGylated fibrin matrix) using MSCs loaded with gold nanoparticles as nanotracers. The objective of the current study was to assess the effects of loading MSCs with gold nanoparticles on cellular function.
In this study, we utilized various gold nanoparticle formulations by varying size and surface coatings and assessed the efficiency of cell labeling using darkfield microscopy. We hypothesized that loading cells with gold nanotracers would not significantly alter cell function due to the inert and biocompatible characteristics of gold. The effect of nanoparticle loading on cell viability and cytotoxicity was analyzed using a LIVE/DEAD stain and an MTT assay. The ability of MSCs to differentiate into adipocytes and osteocytes after nanoparticle loading was also examined. In addition, nanoparticle loading and retention over time was assessed using inductively coupled plasma mass spectrometry (ICP-MS).
Our results demonstrate that loading MSCs with gold nanotracers does not alter cell function and, based on the ICP-MS results, long-term imaging and tracking of MSCs is feasible. These findings strengthen the possibility of imaging MSCs in vivo, such as with optical or photoacoustic imaging, to understand better the participation and role of MSCs in neovascularization.
干细胞可以分化为多种细胞类型，因此可用于细胞疗法，包括组织修复。然而，干细胞在组织修复和新血管生成中的参与情况尚不清楚。因此，需要实施一种非侵入性、长期的成像技术来在体内追踪干细胞，以更好地了解伤口愈合反应。通常，我们有兴趣开发一种成像方法，通过使用负载金纳米粒子的间充质干细胞 (MSCs) 作为纳米示踪剂，通过聚乙二醇修饰的纤维蛋白基质 (PEGylated fibrin matrix) 递送至体内后追踪 MSCs。本研究的目的是评估负载金纳米粒子对细胞功能的影响。
在这项研究中，我们通过改变大小和表面涂层来利用各种金纳米粒子制剂，并通过暗场显微镜评估细胞标记的效率。我们假设由于金的惰性和生物相容性特性，负载细胞的金纳米示踪剂不会显著改变细胞功能。使用 LIVE/DEAD 染色和 MTT 测定分析纳米颗粒负载对细胞活力和细胞毒性的影响。还检查了负载纳米颗粒后 MSCs 向脂肪细胞和成骨细胞分化的能力。此外，还使用电感耦合等离子体质谱法 (ICP-MS) 评估了纳米颗粒负载和随时间的保留情况。
我们的结果表明，负载 MSCs 的金纳米示踪剂不会改变细胞功能，并且基于 ICP-MS 结果，长期成像和追踪 MSCs 是可行的。这些发现增强了在体内对 MSCs 进行成像的可能性，例如使用光学或光声成像，以更好地了解 MSCs 在新血管生成中的参与和作用。
