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Antithrombotic therapy is confronted with short half-lives of thrombolytic agents and high bleeding risks. Challenges remain in the development of drug delivery systems for thorough destruction of thrombi and timely restoration of blood flow while minimizing side effects. Herein, polydopamine capsule-like micromotors with urokinase (uPA) loadings and Arg-Gly-Asp (RGD) grafts (r-u@PCM) were constructed using rod-shaped bacteria as the template, and one single opening was created on each capsule through bacterial ghost (BG) formation. Glucose oxidase and catalase were encapsulated in the large cavity of microcapsules, and their successive oxidation of glucose produced O 2 bubbles, which ejected out through the single opening to propel the motion of r-u@PCM. In vitro targeting testing of r-u@PCM shows significant higher accumulations on the activated platelets than those without RGD grafts (u@PCM, 7 folds) or without enzyme loadings (r-u@PC, 11 folds). Compared with the major distribution of r-u@PC on the clot surface, r-u@PCM efficiently penetrates into clots with dense fibrin networks, and near-infrared (NIR) irradiation (r-u@PCM/NIR) promotes thrombus infiltration through increasing uPA release and thermolysis of the networks. Pharmacokinetic study shows that the loading of uPA in r-u@PCM extends the terminal half-life from 24 min to 5.5 h and the bioavailability increased 13 times. In a hindlimb venous thrombosis model, r-u@PCM/NIR treatment promotes uPA accumulations in thrombi and disrupts all the thrombi after 8 h with a full recovery of blood flows. Effective thrombolysis is also achieved even after reducing the uPA dose 5 times. Thus, this is the first attempt to fabricate rod-shaped microcapsule motors through a biologically derived method, including bacterial templating and BG formation-induced opening generation. r-u@PCM/NIR treatment promotes thrombolysis through the photothermal effect, self-propelled infiltration into thrombi, and accelerated local release of uPA, providing a prerequisite for reducing uPA dose and bleeding side effects.

Effective thrombolysis is critical to rapidly rebuild blood flow for thrombosis patients. Drug delivery systems have been developed to address inadequate pharmacokinetics of thrombolytic agents, but challenges still remain in the timely removal of blood clots regarding the dense fibrin networks. Herein, rod-shaped tubular micromotors were developed to achieve efficient penetration and thorough destruction of thrombi. By using electrospun fiber fragments as the template, urokinase (uPA)-loaded polydopamine (PDA) microtubes with surface decorated fucoidan ( Fu PDA uPA ) were prepared at the aspect ratio of around 2. One E. coli Nissle 1917 (EcN) was assembled into one microtube to construct a Fu PDA uPA @EcN hybrid micromotor through PDA adhesion and L-aspartate induction. The pharmacokinetic analysis indicates that the encapsulation of uPA into micromotors extends the half-life from 0.4 to 5.6 h and increases the bioavailability over 10 times. EcN-propelled motion elevates adsorption capacities of Fu PDA uPA @EcN for more than four times compared with that of Fu PDA uPA . The fucoidan-mediated targeting causes 2-fold higher thrombolysis capacity in vitro and over 10-fold higher uPA accumulation in thrombi in vivo. In the treatment of venous thrombi at mouse hindlimbs, intravenous administration of Fu PDA uPA @EcN completely removed blood clots with almost full recovery of blood flows and apparently alleviated tail bleeding. It should be noted that Fu PDA uPA @EcN treatment at a reduced uPA dose caused no significant difference in the blood flow rate compared with those of Fu PDA uPA . The synergistic action of fucoidan-induced targeting and EcN-driven motion provides a prerequisite for promoting thrombolytic efficacy and reducing uPA dose and bleeding side effect. STATEMENT OF SIGNIFICANCE: The standard treatment to thrombosis patient is intravenous infusion of thrombolytic agents, but the associated bleeding complications and impairment of normal haemostasis greatly offset the therapeutic benefits. Drug delivery systems have been developed to address the limitations of inadequate pharmacokinetics of thrombolytic agents, but challenges still exist in less efficient penetration into dense networks for thorough destruction of thrombi. Up to now only few attempts have been made to construct nano-/micromotors for combating thrombosis and there is no single case that antithrombosis is assisted by bacteria or cells-propelled motors. Herein, bacteria-propelled microtubes were developed to carry urokinase for efficient penetration into blood clots and effective thrombolysis. The synergistic action of bacteria-driven motion and specific ligand-induced targeting holds a promising treatment strategy for life-threatening cardiovascular diseases such as thrombosis and atherosclerosis., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Antithrombosis therapy is confronted with short half-lives of thrombolytic agents, limited therapeutic effects, and bleeding complications. Drug delivery systems of thrombolytic agents face challenges in effective penetration into thrombi, which are characterized by well-organized fibrin filled with abundant activated platelets. Herein, Janus rod (JR)-shaped micromotors are constructed by side-by-side electrospinning and cryosection, possessing advantages in controlling the Janus structure and aspect ratio of microrods. Silicon phthalocyanine (Pc) and CaO 2 nanoparticles (NPs) are loaded into the separate sides of JRs, and Arg-Gly-Asp (RGD) peptides are grafted on the surface to obtain Pc/Ca@r-JRs for the sonodynamic therapy (SDT) of thrombosis without using any thrombolytic agents. Decomposition of CaO 2 NPs ejects O 2 bubbles from one side of JRs, and ultrasonication of O 2 bubbles produces the cavitation effect, both generating mechanical force to drive the thrombus penetration. The integration of ultrasonication-propelled motion and RGD mediation effectively increases the targeting capabilities of r-JRs to activated platelets. In addition to mechanical thrombolysis, ultrasonication of the released Pc produces 1 O 2 to destruct fibrin networks of clots. In vitro thrombolysis of whole blood clots shows that ultrasonication of Pc/Ca@r-JRs has a significantly higher thrombolysis rate (73.6%) than those without propelled motion or RGD-mediated clot targeting. In a lower limb thrombosis model, intravenous administration of Pc/Ca@r-JRs indicates 3.4-fold higher accumulations at the clot site than those of JRs, and ultrasonication-propelled motion further increases thrombus retention 2.1 times. Treatment with Pc/Ca@r-JRs and ultrasonication fully removes thrombi and significantly prolongs tail bleeding time. Thus, this study has achieved precise and prompt thrombolysis through selective targeting to clots, efficient penetration into dense networks of thrombi, and SDT-executed thrombolysis.

Thrombus therapy is challenged by potential bleeding risk of thrombolytic agents, and external irradiation is usually needed in thrombus imaging. Herein, highly efficient theranostic platforms are designed for piezoelectric‐Fenton‐photodynamic thrombolysis and endogenous thrombus imaging in response to the elevated shear stress at the thrombus site. Piezoelectric tetragonal barium titanate (tBT) nanoparticles (NPs) are coated with Fe3+‐coordinated metal‐organic frameworks (MOFs), followed by inoculation of chlorin e6‐luminol conjugates and heparin absorption to obtain theranostic tBT@MOFCL/Hep NPs. Shear stress‐induced piezopotential on NPs accelerates Fe3+/Fe2+ transformation to deplete MOF layers, activates Fenton reaction and produces reactive oxidative species (ROS) for non‐pharmacological thrombolysis. In the meantime, the site‐specific ROS generation oxidizes luminol and the chemiluminescent resonance energy transfer with chlorin e6 generates red fluorescence for thrombus imaging without using external light irradiation. After intravenous injection into a carotid artery thrombosis model, the heparin‐mediated thrombus targeting yields 6.5‐fold higher luminescent intensity at the thrombus site. Thrombi in the carotid arteries are almost completely dissolved with integration of piezoelectric dynamic therapy, piezopotential‐enhanced Fenton reaction, and chemiluminescence‐excited photodynamic therapy, while causing no haematologic and histopathologic abnormality. This study demonstrates a concise strategy to generate shear stress‐responsive built‐in piezoelectric potentials, site‐specific non‐pharmacological thrombolysis, self‐illuminating, and stenosis degree‐adaptable thrombus imaging. [ABSTRACT FROM AUTHOR]

[Display omitted] • Janus micromotors are developed for efficient thrombolysis and inhibition of thrombosis relapse. • Gas bubble generation amplifies cavitation effect of ultrasound to promote thrombus penetration. • Micromotors are equipped with dual targeting capabilities to thrombi and the damaged endothelia. • RGD-mediated accumulation and ultrasound-driven penetration lead to full removal of thrombi. • H 2 O 2 -scavenging and resveratrol release and endothelial repairing inhibit thrombosis recurrence. Thrombosis seriously endangers human health with high incidence and mortality worldwide, and the clinical treatment is challenged by low bioavailability of thrombolytic agents, high bleeding risk and thrombosis relapse. Herein, ultrasound-powered Janus micromotors with stimuli-responsive multiple release capabilities are developed for efficient thrombolysis and inhibition of thrombosis recurrence. Resveratrol-loaded hyaluronic acid (HA Res) nanoparticles (NPs) and urokinase plasminogen activator (uPA) were entrapped into H 2 O 2 -sensitive poly(1,4-cyclohexanedimethanol-co-oxalate) (POX) microparticles (MPs), followed by polydopamine capping and RGD grafting to obtain Janus rJPox@u-HA Res MPs. After RGD-mediated delivery to the thrombus site, the peroxalate ester bonds of POX are oxidized by the elevated H 2 O 2 to produce CO 2 , and the MP collapse accelerates the local release of uPA and HA Res NPs. The resulting CO 2 bubbles amplify the cavitation effect of ultrasound to promote thrombus penetration and site-specific uPA thrombolysis. The endothelial cell targeting and sustained resveratrol release from HA Res NPs dramatically improve endothelial cell viability, nitric oxide production and migration. Compared with free drug administration, the uPA loading into MPs significantly extends the half-life (15 folds) and bioavailability (7 folds), while the resveratrol inoculation into NPs increases the bioavailability 29 times. On an acute lower limb thrombosis model, the thrombus accumulation of MPs is promoted by RGD-mediated interactions with the activated platelets and ultrasound-driven penetration into thrombi, leading to almost full removal of blood clots. The H 2 O 2 -scavenging capability of POX, sustained resveratrol release and efficient thrombolysis alleviate oxidative stresses, eliminate coagulation biomarkers and repair the damaged endothelial layer to effectively inhibit thrombosis relapse. It is demonstrated that rJPox@u-HA Res /US treatment could not only achieve safe and site-specific thrombolytic therapy at the early stage but also restore vascular homeostasis to effectively prevent thrombosis recurrence. [ABSTRACT FROM AUTHOR]