Exosomes are subtypes of vesicles secreted by almost all cells and can play an important role in intercellular communication. They contain various proteins, lipids, nucleic acids and other natural substances from their metrocytes. Exosomes are expected to be a new generation of drug delivery systems due to their low immunogenicity, high potential to transfer bioactive substances and biocompatibility. However, exosomes themselves are not highly targeted, it is necessary to develop new surface modification techniques and targeted drug delivery strategies, which are the focus of drug delivery research. In this review, we introduced the biogenesis of exosomes and their role in intercellular communication. We listed various advanced exosome drug-loading techniques. Emphatically, we summarized different exosome surface modification techniques and targeted drug delivery strategies. In addition, we discussed the application of exosomes in vaccines and briefly introduced milk exosomes. Finally, we clarified the clinical application prospects and shortcomings of exosomes.

中文翻译：

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外泌体作为靶向递送药物系统：外泌体负载、表面功能化和临床应用潜力的进展

外泌体是几乎所有细胞分泌的囊泡亚型，在细胞间通讯中发挥重要作用。它们含有来自母细胞的各种蛋白质、脂质、核酸和其他天然物质。外泌体因其低免疫原性、高转移生物活性物质的潜力和生物相容性而有望成为新一代药物递送系统。然而，外泌体本身靶向性不强，需要开发新的表面修饰技术和靶向药物递送策略，这是药物递送研究的重点。在这篇综述中，我们介绍了外泌体的生物发生及其在细胞间通讯中的作用。我们列出了各种先进的外泌体载药技术。我们重点总结了不同的外泌体表面修饰技术和靶向药物递送策略。此外，我们讨论了外泌体在疫苗中的应用，并简要介绍了牛奶外泌体。最后，我们阐明了外泌体的临床应用前景和不足。