School of Medicine, Imperial College London, London. United Kingdom.
Department of Anaesthesia, Royal Free London NHS Foundation Trust, London. United Kingdom.
Curr Pharm Des. 2017;23(20):2908-2917. doi: 10.2174/1381612823666170215104659.
The study of magnetic nanoparticles (MNPs) for drug delivery has recently seen a surge of interest even though the first studies were conducted as early as in the seventies. Despite this, there are still gaps in the knowledge of the field, implicating the complexities in designing the ideal MNP for drug delivery. The large surface area of MNPs and the ability to manipulate with an externally applied magnetic field render the MNP a good candidate for targeted delivery of drugs. Drugs are conjugated to the surface of MNPs or encapsulated within, while the surface of MNPs receives a protective coating and is functionalised with ligands, enzymes, linkers, and active molecules to deliver the drug to a targeted site.
These MNPs in the form of nanogels, micelles, polymers, dendrimers, and receptor-targeted have been studied in vitro and in vivo to assess morphology, cytotoxicity, localisation and others, which are the indicators of efficacy. While preclinical studies appear to be promising, there is a limited translation from bench to bedside for reasons such as inconsistent results between similar studies and inadequate profiles of toxicity, drug release and biodistribution amongst many others. However, the substantial number of clinical trials of MNPs in other applications such as hyperthermia for the treatment of cancer and imaging shows that there is indeed potential in the development of MNPs to achieve successful drug delivery.
The lack of optimal design for MNP surface functionalization and conjugation to drug and other molecules for delivery to target cells gives plenty of room for the research and development of the ideal MNP, which is indicated for the future of MNPs in biomedical applications.
尽管早在 70 年代就进行了最早的研究，但磁性纳米粒子（MNPs）在药物输送方面的研究最近还是引起了广泛关注。尽管如此，该领域的知识仍存在空白，这意味着设计用于药物输送的理想 MNPs 具有复杂性。MNPs 的大表面积和对外加磁场的操纵能力使 MNPs 成为药物靶向输送的良好候选物。药物被共轭到 MNPs 的表面上或包裹在其中，而 MNPs 的表面则接受保护层并与配体、酶、连接子和活性分子结合，以将药物递送到靶向部位。
这些以纳米凝胶、胶束、聚合物、树突状聚合物和受体靶向形式的 MNPs 已经在体外和体内进行了研究，以评估形态、细胞毒性、定位等，这些都是疗效的指标。尽管临床前研究似乎很有前景，但由于类似研究之间结果不一致以及毒性、药物释放和生物分布等方面的概况不足等原因，从实验室到临床的转化有限。然而，大量关于 MNPs 在其他应用（如癌症热疗中的应用）的临床试验和成像表明，开发 MNPs 以实现成功的药物输送确实具有潜力。
缺乏对 MNPs 表面功能化和与药物及其他分子的共轭进行优化设计，以将其递送到靶细胞，这为研究和开发理想的 MNPs 提供了充分的空间，这表明 MNPs 在生物医学应用中的未来具有广阔的前景。
