This paper elucidates the feasibility of magnetic drug targeting to the eye by using magnetic nanoparticles (MNPs) to which pharmaceutical drugs can be linked. Numerical simulations revealed that a magnetic field gradient of 20 T m-1 seems to be promising for dragging magnetic multicore nanoparticles of about 50 nm into the eye. Thus, a targeting magnet system made of superconducting magnets with a magnetic field gradient at the eye of about 20 T m-1 was simulated. For the proof-of-concept tissue experiments presented here the required magnetic field gradient of 20 T m-1 was realized by a permanent magnet array. MNPs with an optimized multicore structure were selected for this application by evaluating their stability against agglomeration of MNPs with different coatings in water for injections, physiological sodium chloride solution and biological media such as artificial tear fluid. From these investigations, starch turned out to be the most promising coating material because of its stability in saline fluids due to its steric stabilization mechanism. To evaluate the passage of MNPs through the sclera and cornea of the eye tissues of domestic pigs (Sus scrofa domesticus), a three-dimensionally printed setup consisting of two chambers (reservoir and target chamber) separated by the eye tissue was developed. With the permanent magnet array emulating the magnetic field gradient of the superconducting setup, experiments on magnetically driven transport of the MNPs from the reservoir chamber into the target chamber via the tissue were performed. The resulting concentration of MNPs in the target chamber was determined by means of quantitative magnetic particle spectroscopy. It was found that none of the tested particles passed the cornea, but starch-coated particles could pass the sclera at a rate of about 5 ng mm-2 within 24 h. These results open the door for future magnetic drug targeting to the eye.

中文翻译：

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磁性纳米粒子通过眼组织的磁驱动通道用于磁性药物靶向的研究

本文阐明了通过使用可以连接药物的磁性纳米粒子 (MNP) 将磁性药物靶向眼睛的可行性。数值模拟表明，20 T m-1 的磁场梯度似乎有希望将约 50 nm 的磁性多核纳米粒子拖入眼睛。因此，模拟了一个由超导磁体制成的目标磁体系统，其眼部磁场梯度约为 20 T m-1。对于此处介绍的概念验证组织实验，所需的 20 T m-1 磁场梯度是通过永磁体阵列实现的。通过评估具有不同涂层的 MNP 在注射用水中的团聚稳定性，选择了具有优化多核结构的 MNP 用于此应用，生理氯化钠溶液和人工泪液等生物介质。从这些研究中，淀粉被证明是最有前途的涂层材料，因为它的空间稳定机制使其在盐水中具有稳定性。为了评估 MNP 通过家猪 (Sus scrofadomesticus) 眼组织的巩膜和角膜，开发了一种由眼组织隔开的两个腔室（储库和目标腔室）组成的三维打印装置。利用永磁体阵列模拟超导装置的磁场梯度，进行了 MNP 从储存室通过组织磁驱动传输到目标室的实验。目标室中 MNP 的最终浓度通过定量磁粒子光谱法确定。发现测试颗粒均未通过角膜，但淀粉包覆颗粒可以在 24 小时内以约 5 ng mm-2 的速率通过巩膜。这些结果为未来磁性药物靶向眼睛打开了大门。