Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, Jeddah, 23955-6900, Saudi Arabia.
Center for Cooperative Research in Biomaterials (CIC biomaGUNE), Basque Research and Technology Alliance (BRTA), Paseo de Miramon 182, 20014, Donostia San Sebastián, Spain.
J Nanobiotechnology. 2020 Mar 12;18(1):42. doi: 10.1186/s12951-020-00597-3.
Identifying the precise location of cells and their migration dynamics is of utmost importance for achieving the therapeutic potential of cells after implantation into a host. Magnetic resonance imaging is a suitable, non-invasive technique for cell monitoring when used in combination with contrast agents.
This work shows that nanowires with an iron core and an iron oxide shell are excellent materials for this application, due to their customizable magnetic properties and biocompatibility. The longitudinal and transverse magnetic relaxivities of the core-shell nanowires were evaluated at 1.5 T, revealing a high performance as T contrast agents. Different levels of oxidation and various surface coatings were tested at 7 T. Their effects on the T contrast were reflected in the tailored transverse relaxivities. Finally, the detection of nanowire-labeled breast cancer cells was demonstrated in T-weighted images of cells implanted in both, in vitro in tissue-mimicking phantoms and in vivo in mouse brain. Labeling the cells with a nanowire concentration of 0.8 μg of Fe/mL allowed the detection of 25 cells/µL in vitro, diminishing the possibility of side effects. This performance enabled an efficient labelling for high-resolution cell detection after in vivo implantation (~ 10 nanowire-labeled cells) over a minimum of 40 days.
Iron-iron oxide core-shell nanowires enabled the efficient and longitudinal cellular detection through magnetic resonance imaging acting as T contrast agents. Combined with the possibility of magnetic guidance as well as triggering of cellular responses, for instance by the recently discovered strong photothermal response, opens the door to new horizons in cell therapy and make iron-iron oxide core-shell nanowires a promising theranostic platform.
在将细胞植入宿主后，确定细胞的确切位置及其迁移动态对于实现细胞的治疗潜力至关重要。磁共振成像（MRI）结合对比剂是一种适用于细胞监测的非侵入性技术。
这项工作表明，具有铁核和氧化铁壳的纳米线是这种应用的理想材料，因为它们具有可定制的磁性能和生物相容性。在 1.5 T 下评估了核壳纳米线的纵向和横向磁共振弛豫率，结果表明它们作为 T 对比剂具有出色的性能。在 7 T 下测试了不同氧化水平和各种表面涂层。它们对 T 对比的影响反映在定制的横向弛豫率中。最后，在体外组织模拟体和体内小鼠脑内植入的细胞的 T 加权图像中，证明了纳米线标记的乳腺癌细胞的检测。用浓度为 0.8μg/mL 的纳米线标记细胞，可在体外检测到 25 个细胞/µL，从而降低了副作用的可能性。这种性能可实现高效标记，从而能够在体内植入后（~10 个纳米线标记细胞）进行高分辨率细胞检测，至少持续 40 天。
铁-氧化铁核壳纳米线可用作 T 对比剂，通过磁共振成像实现高效的纵向细胞检测。结合磁导向的可能性以及触发细胞反应的可能性，例如最近发现的强光热响应，为细胞治疗开辟了新的视野，并使铁-氧化铁核壳纳米线成为一种有前途的治疗诊断平台。
