Table 2.

Summary of representative tPA-loaded nanocarriers

Nanocarriers type	Composition of carrier	Modification	Model	Key findings	Ref
Liposomes	Egg PC, cholesterol, sodium cholesterol-3-sulfate, DSPE-PEG2000	/	/	▪Loading tPA into liposomes did not alter fibrinolytic activity of intact tPA; ▪Encapsulation of tPA into PEGylated liposomes prolonged half-life of tPA by 21 folds compared with free tPA.	28
Liposomes	Egg PC, cholesterol, rhodamine-PE	Anti-actin antibodies	Rat model of embolic focal stroke	▪Antiactin-targeted immunoliposomes significantly reduced tPA-induced hemorrhage.	29
Liposomes	Soy PC, cholesterol, DOPE, DSPE-PEG2000	Activated platelets targeted peptide (CQQHHLGGAKQ AGDV)	Inferior vena-cava rat model of thrombosis	▪Encapsulated tPA retained >90% fibrinolytic activity; ▪The half-life of tPA was extended from 7 to 141 min for pegylated liposomes; ▪Compared to native tPA, liposomal-tPA caused a 35% increase in clot-lysis, but produced a 4.3-fold less depletion of circulating fibrinogen.	31
PLGA nanoparticles (NP)	PLGA, chitosan	GRGD peptide (Gly-Arg-Gly-Asp)	Blood clot-occluded tube model	▪PLGA NP significantly accelerated thrombolysis of tPA	33
PLGA nanoparticles (NP)	PLGA	/	Mouse Pulmonary Embolism Model; Mouse Ferric Chloride Arterial Injury Model	▪Micro-aggregates of PLGA NP could break up and release tPA locally upon exposure to the abnormally high shear stress in occluded vascular; ▪Dose of this shear-activated tPA-nanoparticles was about 100-times lower than that of free drug for achieving comparable clot lysis efficacy.	35
PLGA hydrogel	PLGA, PEG methacrylate, PEG dimethacrylate	/	/	▪Porous structure of the hydrogel facilitated tPA release; ▪Release of tPA from hydrogel could be regulated.	34
Gelatin nanoparticles (NP)	Ethylenediamine cationized gelatins, PEG-gelatin	/	Rabbit thrombosis model	▪Suppressed thrombolytic activity of tPA recovered only when exposed to ultrasound; ▪Half-life of tPA in the blood circulation was prolonged about 3 times; ▪Intravenous administration of PEG-modified gelatin NP followed by ultrasound irradiation resulted in complete recanalization	36
Magnetic nanoparticles (MNP)	Fe3O4	Chitosan coating	Rat embolic model	▪Magnetic guidance lead to effective thrombolysis; ▪One-fifth of the dose of tPA may exert similar thrombolytic efficacy of the drug.	45
Magnetic nanoparticles (MNP)	Fe3O4	Silica coating	Pig stented brachial artery model, in vitro flow-through model	▪Octahedral MNP targeted successfully to a ferromagnetic coil under magnetic guidance; ▪tPA-MNP conjugates showed negligible hemolysis and no short-term adverse effects in pig model.	46
Magnetic nanoparticles (MNP)	γFe2O3	Macrophage-derived microvesicles	/	▪Hybrid cell microvesicles could be manipulated by magnetic force for targeting and subsequent delivery of tPA to specific sites.	47
Magnetic nanoparticles (MNP)	Iron oxide nanocubes (Fe3O4)	Bovine serum albumin coating	Mouse Ferric Chloride Arterial Injury Model	▪tPA when immobilized on MNP displayed 3 orders of magnitude enhanced clot dissolution, and could recanalize occluded vessels within a few minutes by dissolving clots.	49
Micro-bubbles (MB)	sulphur hexafluoride (SF6), phospholipid	/	/	▪A single-step fabrication method (coaxial electrohydrodynamic atomization) was employed to fabricate MB; ▪Maximum tPA payload can reach 109.89 µg tPA/ml MB and tPA still maintained at lease ~80% of its activity.	68
Echogenic liposomes (ELIP)	DPPC, DOPC, DPPG, cholesterol	/	/	▪Entrapment of tPA into ELIP showed effective clot lysis and triggered drug release under ultrasound irritation	71
Echogenic liposomes (ELIP)	DSPC, DSPE-PEG, cholesterol, perfluoropropane gas	RGD peptide (CGGGRGDF)	Acute thrombotic occlusion model of a rabbit iliofemoral artery	▪High-intensity ultrasound exposure with targeted ELIP achieved arterial recanalization in 90% of arteries, and the time to reperfusion was shorter than with tPA treatment.	74
Echogenic liposomes (ELIP)	Perfluorocarbon gas (C4F8), DSPC, DSPE-PEG2000	/	/	▪Microfluidic techniques improved the encapsulation efficiency of both tPA and perflurocarbon microbubbles within ELIP.	79
Electrostatic nanocomplexes	Heparin, albumin-protamine	/	Jugular vein rat thrombosis model	▪Electrostatic nanocomplexes significantly masked the thrombolytic activity of tPA during circulation; ▪Activity of tPA can be triggered at the thrombus site at therapeutic heparin concentration.	80
Electrostatic nanocomplexes	HSA, thrombin-cleavable peptide	Activated platelets targeting peptide: homing peptide (CQQHHLGGAKQ AGDV)	Rat thrombosis model	▪75% activity of tPA was suppressed during circulation but regenerated to ~ 90% when exposed to thrombin; ▪Thrombolytic activity of camouflaged tPA was similar to that of native tPA; ▪Integrity of nanocomplexes was maintained in human plasma or blood; ▪Degradation of circulating fibrinogen was reduced by 2-fold with HSA-decorated tPA compared with that of native tPA.	82

PC: phosphatidylcholine;

Rhodamine-PE: rhodamine-phosphatidyl ethanolamine;

DOPE: dioleoylphosphatidylethanolamine;

PLGA: poly(lactic-co-glycolic acid);

DPPC: Dipalmitoylphosphatidylcholine;

DOPC: dioleoylphosphatidylcholine;

DPPG: 1,2-dipalmitoyl-sn-glycero-3-phosphoglycerol;

DSPC: 1, 2-disteoyl-sn-glycero-phosphocholine;

HSA: human serum albumin