Division of Neuroscience and Experimental Psychology, The University of Manchester, Manchester M13 9PT, United Kingdom; The School of Materials, The University of Manchester, Manchester M13 9PL, United Kingdom.
The School of Materials, The University of Manchester, Manchester M13 9PL, United Kingdom; Pan Tianshou Arts and Design Academy, Ningbo University, No.818, Fenghua Road, Ningbo 315200, China.
Mater Sci Eng C Mater Biol Appl. 2019 Aug;101:217-227. doi: 10.1016/j.msec.2019.03.062. Epub 2019 Mar 19.
Diffusion magnetic resonance imaging (dMRI) is considered as a useful tool to study solid tumours. However, the interpretation of dMRI signal and validation of quantitative measurements of is challenging. One way to address these challenges is by using a standard reference material that can mimic tumour cell microstructure. There is a growing interest in using hollow polymeric microspheres, mainly prepared by multiple steps, as mimics of cells in healthy and diseased tissue. The present work reports on tumour cell-mimicking materials composed of hollow microspheres for application as a standard material in dMRI. These microspheres were prepared via one-step co-electrospraying process. The shell material was poly(d,l-lactic-co-glycolic acid) (PLGA) polymers with different molecule weights and/or ratios of glycolic acid-to-lactic, while the core was polyethylene glycol (PEG) or ethylene glycol. The resultant co-electrosprayed products were characterised by optical microscopy, scanning electron microscopy (SEM) and synchrotron X-ray micro-CT. These products were found to have variable structures and morphologies, e.g. from spherical particles with/without surface hole, through beaded fibres to smooth fibres, which mainly depend on PLGA composition and core materials. Only the shell material of PLGA polymer with ester terminated, Mw 50,000-75,000 g mol, and lactide:glycolide 85:15 formed hollow microspheres via the co-electrospraying process using the core material of 8 wt% PEG/chloroform as the core. A water-filled test object (or phantom) was designed and constructed from samples of the material generated from co-electrosprayed PLGA microspheres and tested on a 7 T MRI scanner. The preliminary MRI results provide evidence that hollow PLGA microspheres can restrict/hinder water diffusion as cells do in tumour tissue, implying that the phantom may be suitable for use as a quantitative validation and calibration tool for dMRI.
扩散磁共振成像（dMRI）被认为是一种研究实体瘤的有用工具。然而，dMRI 信号的解释和定量测量的验证具有挑战性。解决这些挑战的一种方法是使用可以模拟肿瘤细胞微结构的标准参考材料。使用空心聚合物微球作为健康和患病组织中细胞的模拟物越来越受到关注，这些微球主要通过多步制备。目前的工作报道了由空心微球组成的肿瘤细胞模拟材料，可作为 dMRI 中的标准材料应用。这些微球是通过一步共电喷雾工艺制备的。壳材料为聚（丙交酯-乙交酯）（PLGA）聚合物，具有不同的分子量和/或丙交酯与乳酸的比例，而核为聚乙二醇（PEG）或乙二醇。通过光学显微镜、扫描电子显微镜（SEM）和同步加速器 X 射线微 CT 对所得共电喷雾产物进行了表征。这些产物具有不同的结构和形态，例如具有/没有表面孔的球形颗粒、珠状纤维到光滑纤维，这主要取决于 PLGA 组成和核材料。只有具有酯端基、Mw 50,000-75,000 g/mol 的 PLGA 聚合物的壳材料和 8 wt% PEG/氯仿作为核材料，才能通过共电喷雾工艺形成空心微球。设计并构建了一个充水测试对象（或体模），该对象由共电喷雾 PLGA 微球生成的材料样本制成，并在 7T MRI 扫描仪上进行了测试。初步的 MRI 结果表明，空心 PLGA 微球可以像肿瘤组织中的细胞一样限制/阻碍水扩散，这意味着该体模可能适合用作 dMRI 的定量验证和校准工具。
