Design and Development of Degradable Polyethylenimines for Delivery of DNA and Small Interfering RNA: An Updated Review

Table 1

Representative examples of degradable PEIs having ester linkage (modified from [103]).

Type	Mw of starting PEI (Da)	Crosslinkers	Cells	Characters	Reference
	800	1,3-Butanediol diacrylate	MDA-MB-231	4 h half-life, 9-fold higher gene expression	[21]
Linear	423	PEG diacrylate	HepG2; MG63	Importance of MW of PEG, 4 h of half-life, aerosol route is more effective than I.V. one	[24]
	423	Sorbitol dimethacrylate	A549, HeLa, H322	Accelerated gene transfer by hyperosmotic activity; No aggregation of polyplexes after lyophilization	[37]
	800	1,3-Butanediol diacrylate, 1,6-hexane diacrylate	MDA-MB-231	Reaction with primary and secondary amines of PEI	[21]
	800	1,6-Hexane diacrylate	Neuro2a, BI6F10	Reaction temperature controls half-life	[22, 23]
	600, 1200, 1800	Poloxamer diacrylate	A549, 293T, HepG2	Little serum dependency of transfection	[34]
Branched	600, 1200, 1800	Polycaprolactone diacrylate	293T, HepG2, HeLa	25-fold higher gene expression, 5 h of half-life	[35]
	1200	Glycerol dimethacrylate	HeLa, HepG2, 293T	Synergistic effect of hyper osmotic glycerol and buffering capacity of PEI	[36]
	600, 1200, 1800	PEG dimethacrylate	293T, HeLa, HepG2	Longer half-life than PEG diacrylate	[54]
	1200	Sorbitol diacrylate	A549, HeLa, 293T	Selective caveolae endocytosis pathway by osmotic polysorbitol	[55]
	1200	Mannitol diacrylate	A549, HeLa, N2a	Avoidance of delivered gene from lysosomal fusion by shifting to caveolae endocytosis pathway	[56]
Grafted	800	PEG dithiothreitol	HeLa, MCF-7, COS-7	1,1′-Carbonyldiimidazole was used as a linker. A slight serum dependency in transfection activity	[50]