Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge, CB3 OHE, UK.
The Institute for Translational Nanomedicine, Shanghai East Hospital; The Institute for Biomedical Engineering & Nano Science, Tongji University School of Medicine, Shanghai, 200120, China.
Sci Rep. 2017 Jun 26;7(1):4257. doi: 10.1038/s41598-017-04154-1.
We demonstrate the effectiveness of out-of-plane magnetized magnetic microdiscs for cancer treatment through mechanical cell disruption under an applied rotating magnetic field. The magnetic particles are synthetic antiferromagnets formed from a repeated motif of ultrathin CoFeB/Pt layers. In-vitro studies on glioma cells are used to compare the efficiency of the CoFeB/Pt microdiscs with Py vortex microdiscs. It is found that the CoFeB/Pt microdiscs are able to damage 62 ± 3% of cancer cells compared with 12 ± 2% after applying a 10 kOe rotating field for one minute. The torques applied by each type of particle are measured and are shown to match values predicted by a simple Stoner-Wohlfarth anisotropy model, giving maximum values of 20 fNm for the CoFeB/Pt and 75 fNm for the Py vortex particles. The symmetry of the anisotropy is argued to be more important than the magnitude of the torque in causing effective cell destruction in these experiments. This work shows how future magnetic particles can be successfully designed for applications requiring control of applied torques.
我们通过在施加的旋转磁场下进行机械细胞破裂，证明了平面外磁化的磁性微盘在癌症治疗中的有效性。这些磁性颗粒是由超薄膜 CoFeB/Pt 层重复图案形成的合成反铁磁体。我们利用体外胶质瘤细胞研究来比较 CoFeB/Pt 微盘和 Py 涡旋微盘的效率。结果发现，与施加 10kOe 旋转磁场一分钟后 12 ± 2%的细胞相比，CoFeB/Pt 微盘能够破坏 62 ± 3%的癌细胞。我们测量了每种粒子施加的扭矩，并将其与简单的斯通纳-沃尔夫哈特定向各向异性模型预测的值进行了比较，CoFeB/Pt 的最大扭矩值为 20 fNm，Py 涡旋粒子的最大扭矩值为 75 fNm。实验认为，各向异性的对称性比扭矩的大小更重要，它决定了这些实验中是否能有效破坏细胞。这项工作展示了如何为需要控制施加扭矩的应用设计未来的磁性颗粒。
