Table 1.

Different types of exosomes originated from various sources and their properties.

Types	Source	Features	Limitations	References
Cell-secreted exosomes	Human embryonic kidney (HEK) cells	Membrane resemblances to various tissues in our body Immunologically inert High efficiency in transfection	Low yield compared to body fluid and food-derived exosomes	[31,32]
	Cancer cells	Tropism toward their parent cells	Less ideal pharmacokinetic profile Lack of studies for metastatic role of cancer cell exosomes	[33,34,35]
	Immune cells (e.g., dendritic cells)	Strictly defined molecular compositions Expression of NK cell-stimulating ligand peptides Surface modification using targeting moieties	Lack of understanding of DEX components (e.g., mRNAs, miRs, and cytokines) and mechanisms regarding how these factors interact with acceptor cells	[36,37,38,39,40]
	Stem cells (e.g., mesenchymal stem cell)	Easy availability from ethically acceptable tissues Large capacity for ex vivo expansion	Similar to other types of exosomes (e.g., lack of PK database and need to improve production efficiency)	[41,42,43]
Blood-derived exosomes	Blood (red blood cells)	Relatively high yield from a single blood unit Reduced unexpected mutations from cell culture No occurring horizontal gene transfer Non-toxic/immunogenic by matching blood types High transfection efficiency	Not determined	[43,44]
Food-derived exosomes	Milk-derived exosomes	Dosing through less-invasive oral cavity Functionalized by simple post-insertion	Variation in shape, size, and cargo contents of exosomes depending on the diet and condition of the source Less understanding of the endogenous biological cargo of milk exosomes	[45,46,47,48]
	Edible plants-derived exosomes (e.g., ginger, grapes, lemon, etc.)		Limited knowledge of cellular molecular properties of PDEs	[49,50,51]