Nejadnik Hossein, Jung Kyung Oh, Theruvath Ashok J, Kiru Louise, Liu Anna, Wu Wei, Sulchek Todd, Pratx Guillem, Daldrup-Link Heike E
Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, CA, 94305, USA.
Department of Radiation Oncology, Stanford University, CA, 94305, USA.
Theranostics. 2020 May 15;10(13):6024-6034. doi: 10.7150/thno.39554. eCollection 2020.
Autologous therapeutic cells are typically harvested and transplanted in one single surgery. This makes it impossible to label them with imaging biomarkers through classical transfection techniques in a laboratory. To solve this problem, we developed a novel microfluidic device, which provides highly efficient labeling of therapeutic cells with imaging biomarkers through mechanoporation. Studies were performed with a new, custom-designed microfluidic device, which contains ridges, which compress adipose tissue-derived stem cells (ADSCs) during their device passage. Cell relaxation after compression leads to cell volume exchange for convective transfer of nanoparticles and nanoparticle uptake into the cell. ADSCs were passed through the microfluidic device doped with iron oxide nanoparticles and F-fluorodeoxyglucose (FDG). The cellular nanoparticle and radiotracer uptake was evaluated with DAB-Prussian blue, fluorescent microscopy, and inductively coupled plasma spectrometry (ICP). Labeled and unlabeled ADSCs were imaged as well as in pig knee specimen with magnetic resonance imaging (MRI) and positron emission tomography (PET). relaxation times and radiotracer signal were compared between labeled and unlabeled cell transplants using Student T-test with p<0.05. We report significant labeling of ADSCs with iron oxide nanoparticles and F-FDG within 12+/-3 minutes. Mechanoporation of ADSCs with our microfluidic device led to significant nanoparticle (> 1 pg iron per cell) and F-FDG uptake (61 mBq/cell), with a labeling efficiency of 95%. The labeled ADSCs could be detected with MRI and PET imaging technologies: Nanoparticle labeled ADSC demonstrated significantly shorter relaxation times (24.2±2.1 ms) compared to unlabeled cells (79.6±0.8 ms) on MRI (p<0.05) and F-FDG labeled ADSC showed significantly higher radiotracer uptake (614.3 ± 9.5 Bq / 1×10 cells) compared to controls (0.0 ± 0.0 Bq/ 1×10 cells) on gamma counting (p<0.05). After implantation of dual-labeled ADSCs into pig knee specimen, the labeled ADSCs revealed significantly shorter relaxation times (41±0.6 ms) compared to unlabeled controls (90±1.8 ms) (p<0.05). The labeling of therapeutic cells with our new microfluidic device does not require any chemical intervention, therefore it is broadly and immediately clinically applicable. Cellular labeling using mechanoporation can improve our understanding of biodistributions of therapeutic cells and ultimately improve long-term outcomes of therapeutic cell transplants.
自体治疗细胞通常在一次手术中采集并移植。这使得在实验室中通过经典转染技术用成像生物标志物对它们进行标记变得不可能。为了解决这个问题，我们开发了一种新型微流控装置，它通过机械穿孔实现用成像生物标志物对治疗细胞进行高效标记。研究使用了一种新的、定制设计的微流控装置，该装置包含脊状物，在脂肪组织衍生干细胞（ADSCs）通过装置时对其进行压缩。压缩后的细胞松弛导致细胞体积交换，以实现纳米颗粒的对流转移并使纳米颗粒摄取到细胞中。将ADSCs通过掺杂有氧化铁纳米颗粒和F - 氟脱氧葡萄糖（FDG）的微流控装置。用DAB - 普鲁士蓝、荧光显微镜和电感耦合等离子体质谱法（ICP）评估细胞对纳米颗粒和放射性示踪剂的摄取。对标记和未标记的ADSCs以及猪膝关节标本进行磁共振成像（MRI）和正电子发射断层扫描（PET）成像。使用学生t检验比较标记和未标记细胞移植之间的弛豫时间和放射性示踪剂信号，p<0.05。我们报告在12±3分钟内ADSCs被氧化铁纳米颗粒和F - FDG显著标记。用我们的微流控装置对ADSCs进行机械穿孔导致显著的纳米颗粒摄取（每细胞>1 pg铁）和F - FDG摄取（61 mBq/细胞），标记效率为95%。标记的ADSCs可以用MRI和PET成像技术检测到：在MRI上，纳米颗粒标记的ADSCs与未标记的细胞相比，弛豫时间显著缩短（24.2±2.1 ms对79.6±0.8 ms）（p<0.05），并且在γ计数中，F - FDG标记的ADSCs与对照相比，放射性示踪剂摄取显著更高（614.3±9.5 Bq / 1×10个细胞对0.0±0.0 Bq/ 1×10个细胞）（p<0.05）。将双标记的ADSCs植入猪膝关节标本后，与未标记的对照相比，标记的ADSCs显示出显著更短的弛豫时间（41±0.6 ms对90±1.8 ms）（p<0.05）。用我们的新型微流控装置对治疗细胞进行标记不需要任何化学干预，因此在临床上具有广泛且即时的适用性。使用机械穿孔进行细胞标记可以增进我们对治疗细胞生物分布的理解，并最终改善治疗性细胞移植的长期效果。
