Natural and artificial exosomes for translational nanomedicine

Exosomes are spherical extracellular nanovesicles of endosomal origin, whose function is to encapsulate part of the contents of the parent cells producing them and transport this content to the target recipient cells using biological fluids. Due to their properties, exosomes are considered as potential biological drug delivery systems. For medical purposes, exosomes are isolated from various natural sources. The use of each type of exosome for therapeutic purposes has its advantages and is associated to varying degrees with several biological (stability, immunogenicity, toxicity) and technical (production scaling-up, standardization of isolation protocols, drug loading) problems. Exosomes derived from human cells have significant potential as therapeutic drug (TD) delivery vehicles due to their endogenous origin. However, simultaneously with the delivery of TD, they can carry potentially dangerous biomolecules. Farm animal milk-derived exosomes and exosome-like plant-derived extracellular vesicles have enormous therapeutic potential in themselves and are safe as drug delivery vehicles. However, data on their effects on the human body are limited. Artificial exosomes created with the help of nanobiotechnology can overcome many of the technical limitations inherent in natural exosomes. The review discusses the strengths and limitations of different types of natural and artificial exosomes as drug delivery nanocarriers, as well as challenges associated with their implementation in clinical practice.