TABLE I.

Diverse nanostructures and thin-film coatings developed on stents which have been tested in various animal models.

Type of surface on stents	Description	Development technique	Drug/biologics	Animal model	Results	References
Nanotubular structures	Titanium dioxide nanotubes (Ti stent)	Anodization	⋯	In vivo rabbit iliac artery	Enhanced endothelialization and minimal in-stent restenosis	89
Nanostructures	Titanium dioxide nanoleaves (SS stent)	TiO2 sputter deposition followed by hydrothermal	⋯	In vivo rabbit iliac artery	Reduction of neointima and complete endothelialization	102
	Nanoflaky MgF2 film (Mg–Nd–Zn–Zr stent)	Chemical conversion treatment	⋯	In vivo rabbit abdominal aorta	Complete endothelial lining with minimal thrombogenicity and restenosis	110
	VSMC biomimetic patterns (SS stent)	Femtosecond laser processing	⋯	In vivo rabbit iliac artery	Rapid re-endothelialization in thirty days	121
	Ta implanted nanoridges (CC stent)	Target-ion-induced plasma sputtering	⋯	In vivo rabbit iliac artery	Minimal neointimal hyperplasia and rapid re-endothelialization	125
	Nanosized silicone filament (CC stent)		Anti-CD164 antibody	In vivo porcine coronary artery	Improved selective EPC capture resulting in rapid endothelial healing in 1 week	129
	Nanoporous alumina (SS stent)	Physical vapor deposition of aluminum followed by electrochemical conversion	Tacrolimus	In vivo rabbit iliac artery	Inhibited neointimal proliferation	131
				In vivo porcine coronary artery	Particle debris resulting from the cracking of ceramic coating during stent expansion resulted in increased neointimal growth and stenosis	132
	Nanoporous structures (SS stent) (Lepu Medical Technologies, China)	Electrochemical method to generate pores	Sirolimus and anti-CD34 antibody/anti-CD34 alone	In vivo porcine coronary artery	Endothelialization in 2 weeks with minimal restenosis	135, 136
			CREG gene		Accelerated endothelium in 4 weeks	137
			Rapamycin and probucol		As safe as BMS and SES without any significant enhancement in re-endothelialization	138
Nano-thin-film coatings	Titanium nitride coating (SS stent)	Reactive physical vapor deposition	⋯	In vivo porcine coronary artery	Reduced neointimal hyperplasia	147
	Ti–O film (CC stent)	Magnetron sputter deposition	⋯	In vivo rabbit abdominal aorta	Faster rate of endothelialization	151
	Titanium nano-thin-film coating (SS stent)	Sol-gel processing	⋯	In vivo porcine coronary artery	Non-inferior to BMS	154
	Copper-doped TiO2 nanofilms (Ti wire)	Sol-gel spin-coating	⋯	In vivo Rat abdominal aorta	Reduced neointimal hyperplasia and re-endothelialization in 4 weeks	156
	TiO2 thin films (CC stent)	Plasma-enhanced chemical vapor deposition	Heparin	In vivo porcine coronary artery	Reduced neointima, inflammation and fibrin deposition	157
			Abciximab/alpha lipoic acid		Effective reduction of in-stent restenosis and accelerated re-endothelialization	158
			Abciximab and Kruppel-like factor 4 gene		Reduced neointimal thickening and faster endothelialization	159
	Nitrogen-doped TiO2 thin films	Plasma-enhanced chemical vapor deposition	Tacrolimus	In vivo porcine coronary artery	Reduced in-stent restenosis and increased endothelial formation	160
			Everolimus		Decreased neointimal thickening and thrombosis with faster healing	161
	Nanothin TiO2 film (SS stent)	Radio frequency magnetron sputtering	REDV peptide	In vivo rabbit iliac artery	Reduced in-stent restenosis and promoted re-endothelialization	162
	Nanothin DLC (CC stent)	Physical vapor deposition	⋯	In vivo porcine coronary artery	Early and complete endothelial healing in 30 days and decreased neointimal proliferation at 180 days	166
	Nanothin DLC (NiTi stent)	Physical vapor deposition	⋯	In vivo canine iliac artery model	Significantly lower neointimal hyperplasia	167
	Nanothin polyzene F coating (CC stent)	Deposited from a solution and subsequently dried	⋯	In vivo rabbit iliac artery	Rapid healing in 1 week	182
				In vivo porcine coronary artery	Complete endothelial coverage and reduced neointimal hyperplasia and inflammation	183, 184