Table 1.

Summary of engineering methods of biomembranes and introduced additional functions

Source cells	Inherent functions	Engineering methods	Introduced additional functions	Particle size (nm)	References
Red blood cells	Prolong blood circulation time; Abnormal RBCs can target the mononuclear macrophage system.	Postinsertion method	Enhance targeting ability	75-200	52,73-76
			Cross physiological barriers
T cells	Avoid being cleared by the immune system; Target tumor sites.	Metabolic engineering	Enhance targeting ability	75	82
Macrophage cells	Avoid being cleared by the immune system; Target inflammatory or tumor sites.	Postinsertion method	Cross physiological barriers; Enhance targeting ability	123	29
Neutrophil cells	Avoid being cleared by the immune system; Extravasate across inflamed endothelial layer.	Chemical method	Enhance targeting ability	70	85
Dendritic cells	Avoid being cleared by the immune system; Present antigens to stimulate an immune response.	Metabolic engineering	Link immune-stimulatory ligands	240	87
Cancer cells	Prolong blood circulation time; Homotypic targeting capability; Present antigens to stimulate an immune response.	Gene engineering	Enhance targeting ability; Cross physiological barriers; Link therapeutic ligands	84-175	34, 91-93
		Postinsertion method
		Metabolic engineering
Platelets	Prolong blood circulation time; Target damaged vasculature; Target pathogenic bacteria and cancer cells.	Chemical method; Postinsertion method	Link therapeutic ligands; Enhance targeting ability	106-122	100-101
Exosomes	The contents are inherited from the source cells; Certain types of exosomes can cross the blood-brain barrier.	Chemical method	Enhance targeting ability; Prolong blood circulation	113-143	38, 112-113, 115-116
		Gene engineering
		Postinsertion method