Table 1.

Summary of liquid/gel embolic agents in development

Liquid/Gel Embolic Agents	Mechanism	Special Delivery System	Radiopacity	Therapeutic Carrier	In vivo Embolization	Ref.
Iodine-containing cellulose mixed esters	Precipitation	No	Covalently bonded iodinated compounds	N/A	Sheep aorta	[257]
Iodobenzyl ethers of PVA	Precipitation	No	Covalently bonded iodinated compounds	N/A	N/A	[192a]
Calcium alginate	Ionic crosslinking	Yes	No	N/A	Rabbit kidney	[258]
		Yes	No	N/A	Porcine aneurysm (temporary balloon protection)	[259]
		Yes	Iothalamate meglumine and tantalum powders	N/A	Porcine rete mirabile	[260]
		Yes	Iohexol	N/A	Rabbit pelvic vasculature and saccular aneurysm	[261]
BAB-type HEMA/NIPAAm triblock copolymers	Temperature triggered gelation	No	Iopromide	N/A	Porcine rete mirabile and kidney	[262]
N-isopropylacrylamide (NIPAAm)–N-propylacrylamide (NPAAm)–vinyl pyrrolidone (VP) terpolymers (PNINAVP)	Temperature triggered gelation	No	Iohexol	N/A	Porcine rete mirabile	[263]
p(N-isopropylacrylamide-co-butyl methacrylate) (PNIPAM) based nanogel	Temperature triggered gelation	No	Iohexol	N/A	Rabbit kidney	[264]
		No	Iohexol	N/A	Rabbit renal artery and VX2 liver tumor	[265]
P407-sodium alginate-HPMC-iodixanol hydrogel (PSHI-Ca2+)	Temperature triggered gelation	No	Iodixanol	N/A	Rabbit kidney and VX2 liver tumor	[266]
Chitosan / β-glycerophosphate	Temperature triggered gelation	No	Tantalum powders	N/A	Rabbit renal artery	[267]
		No	Tantalum powders or iohexol	N/A	Porcine basicranial rete mirabile	[268]
		No	Iopamidol	Sodium tetradecyl sulfate	Canine bilateral illiac aneurysm with endoleaks	[269]
		No	Iodixanol	N/A	Porcine splenic and gastric vessels	[270]
Silk-elastin-like protein polymer (SELP)	Temperature triggered gelation	No	No	N/A	Rabbit hepatic artery	[271]
		No	No	Doxorubicin, sorafenib	Rat McA-RH7777 liver tumor	[272]
Sulfamethzaine (SM)-based hydrogels	pH triggered gelation	No	Ethiodized oil	Doxorubicin	Rabbit VX2 liver tumor	[273]
		No	Iohexol	N/A	Rabbit kidney and liver	[274]
		No	Ethiodized oil or iohexol	Doxorubicin	Rabbit VX2 liver tumor	[275]
Poly(amino ester urethane) (PAEU) block copolymers	pH triggered gelation	No	Ethiodized oil	Doxorubicin	Rabbit VX2 liver cancer model	[276]
Poly(propylene glycol) diacrylate (PPODA)-pentaerythritol tetrakis 3-mercaptopropionate (QT) system	Pre-activated chemical crosslinking	No	Iothalamate meglumine	N/A	Porcine lateral wall carotid artery aneurysm (temporary balloon protection)	[277]
		No	Iothalamate meglumine	N/A	Canine lateral wall aneurysm (temporary balloon protection)	[278]
Graphene-oxide (GO) enhanced generation five poly(amidoamine) dendrimers (PAMAM-5) hydrogel	Pre-activated chemical crosslinking	No	Iohexol	N/A	Rabbit subclavian arteries	[256]
Chitosan-doxycycline hydrogel	Temperature triggered gelation	No	Iodixanol	Doxycycline	Porcine renal artery	[279]
Carbazochrome-containing chitosan-PEG hydrogel (PCC)	Pre-activated chemical crosslinking	No	No	Carbazochrome	Rat kidney	[280]
Carboxymethyl chitosan and oxidized carboxymethyl cellulose based hydrogel	Pre-activated chemical crosslinking	No	Ioversol	Tetracycline, doxorubicin	Rabbit kidney	[176]
Dual-gelling poly(NIPAAm) based systems	Temperature triggered gelation and pre-activated chemical crosslinking	No	No	N/A	Porcine aneurysm (temporary balloon protection)	[281]
Phytantrol based liquid crystal	Water/Physiological fluid induced gelation	No	No	Hydroxycamptothecin	N/A	[282]
			No	Docetaxel	Rabbit hepatic artery	[283]
Glyceryl monooleate (GMO) based liquid crystal	Water/Physiological fluid induced gelation	No	Tantalum powder	N/A	Rabbit renal artery	[284]
Polycationic salmine sulfate (Sal)-polyanionic sodium inositol hexaphosphate (IP6) coacervate (Sal-IP6)	Ionic strength difference (NaCl) induced gelation	No	Tantalum powder	N/A	Rabbit kidney	[285]
Polyphosphate based coacervates	Cation-induced phase separation	Yes	Sr, Ba	N/A	Rabbit auricular arteries	[286]
Gelatin and silicate nanoplatelets based shear thinning biomaterial (STB)	Flow-induced shear thinning	No	Iodixanol	N/A	Mouse femoral arteries; porcine lumbar artery, external iliac artery and forelimb veins	[10]