Exosomes are a subpopulation of cell membrane-derived vesicles which play an essential role in cellular communication. In recent years, several studies have exploited the natural properties of exosomes as nanocarriers for several applications such as immunotherapy or drug delivery. Consequently, numerous techniques have been developed to improve their immunogenicity, drug loading efficiency, or targeting. Nonetheless, to date, there is no consensus on which technique results in more advantages for this purpose. In this context, this review discusses the currently used methodologies regarding traditional and engineered exosome loading and targeting techniques. Here, we focus on the advantages and disadvantages of each method while discussing some results obtained in relevant reports. Although there is a lack of evidence regarding the effects of exogenous exosomes in humans and several limitations in exosome isolation and purification techniques at the large-scale exist, the formulation of new exosome-based therapeutics is in the spotlight. Therefore, the development of more efficient functionalization techniques is required to reduce the potential risks associated with the clinical use of these vesicles.

外来体是细胞膜来源的囊泡的亚群，其在细胞通讯中起重要作用。近年来，一些研究已经利用外泌体作为纳米载体的天然特性来进行多种应用，例如免疫疗法或药物递送。因此，已经开发了许多技术来改善其免疫原性，载药效率或靶向性。但是，迄今为止，对于哪种技术可以为此目的带来更多优势，目前尚无共识。在这种情况下，这篇综述讨论了有关传统的和工程化的外来体加载和靶向技术的当前使用的方法。在这里，我们在讨论相关报告中获得的一些结果时，将重点放在每种方法的优缺点上。尽管缺乏关于外源性外泌体在人类中的作用的证据，并且大规模存在外泌体分离和纯化技术的一些局限性，但基于外泌体的新型治疗药物的配方已成为人们关注的焦点。因此，需要开发更有效的功能化技术以减少与这些囊泡的临床使用相关的潜在风险。