Urokinase-coated chitosan nanoparticles for thrombolytic therapy: preparation and pharmacodynamics in vivo

Magnetically Powered Microrobotic Swarm for Integrated Mechanical/Photothermal/Photodynamic Thrombolysis

Current thrombolytic drugs exhibit suboptimal therapeutic outcomes and potential bleeding risks due to their limited circulation time, inadequate thrombus penetration, and off-target biodistribution. Herein, a photosensitizer-loaded, red cell membrane-encapsuled multiple magnetic nanoparticles aggregate is successfully developed for integrated mechanical/photothermal/photodynamic thrombolysis. Red cell membrane coating endows magnetic particles with prolonged blood circulation and superior biocompatibility. Under a preset rotating magnetic field (RMF), the aggregate with asymmetric magnetic distribution initiates rolling motion toward the blood clot interface, and because of magnetic dipole-dipole interactions, the aggregate tends to self-assemble into longer, flexible chain-like microrobotic swarm with powerful mechanical stir forces, thereby facilitating thrombus penetration and mechanical thrombolysis. Moreover, precise magnetic control enables targeted photosensitizer accumulation, allowing effective conversion of near-infrared (NIR) light into heat and reactive oxygen species (ROS) for thrombus phototherapy. In thrombolysis assays, the weight of thrombi is massively reduced by ≈90%. The work presents a safer and more promising combination of magnetic microrobotic technology and phototherapy for multi-modality thrombolysis.

Urokinase-Type Plasminogen Activator Receptor (uPAR) in Inflammation and Disease: A Unique Inflammatory Pathway Activator

The urokinase-type plasminogen activator receptor (uPAR) is a unique protease binding receptor, now recognized as a key regulator of inflammation. Initially, uPA/uPAR was considered thrombolytic (clot-dissolving); however, recent studies have demonstrated its predominant immunomodulatory functions in inflammation and cancer. The uPA/uPAR complex has a multifaceted central role in both normal physiological and also pathological responses. uPAR is expressed as a glycophosphatidylinositol (GPI)-linked receptor interacting with vitronectin, integrins, G protein-coupled receptors, and growth factor receptors within a large lipid raft. Through protein-to-protein interactions, cell surface uPAR modulates intracellular signaling, altering cellular adhesion and migration. The uPA/uPAR also modifies extracellular activity, activating plasminogen to form plasmin, which breaks down fibrin, dissolving clots and activating matrix metalloproteinases that lyse connective tissue, allowing immune and cancer cell invasion and releasing growth factors. uPAR is now recognized as a biomarker for inflammatory diseases and cancer; uPAR and soluble uPAR fragments (suPAR) are increased in viral sepsis (COVID-19), inflammatory bowel disease, and metastasis. Here, we provide a comprehensive overview of the structure, function, and current studies examining uPAR and suPAR as diagnostic markers and therapeutic targets. Understanding uPAR is central to developing diagnostic markers and the ongoing development of antibody, small-molecule, nanogel, and virus-derived immune-modulating treatments that target uPAR.

Nanomicrosphere sustained-release urokinase systems with antioxidant properties for deep vein thrombosis therapy

Deep vein thrombosis (DVT) is a venous return disorder caused by abnormal clotting of blood in deep veins. After thrombosis, most of the thrombus will spread to the deep vein trunk throughout the limb. If DVT is not treated in time, most of them will develop into thrombosis sequelae and even threaten life. Intravenous thrombolytic drugs are the most promising strategy for treating DVT, but current drugs used for thrombolysis suffer from short half-lives and narrow therapeutic indexes. To effectively manage DVT, it is necessary to develop a novel multifunctional drug-loading system to effectively prolong the treatment time and improve the therapeutic efficacy. In this study, a urokinase-loaded protocatechuic aldehyde-modified chitosan microsphere drug-loading platform was constructed for the treatment of DVT. This microsphere adsorbed urokinase well through electrostatic interaction, and the introduction of bovine serum albumin conferred stability to the microspheres. Therefore, the microsphere drug delivery system could achieve slow drug release to effectively dissolve blood fibrin. In addition, chitosan grafted with protocatechuic aldehyde imparted excellent antioxidant activity to the system to reduce free radicals in the blood vessels. Effective management of oxidative stress could avoid abnormal platelet activation and new thrombus formation. The experimental results showed that this microsphere had good biocompatibility, anti-inflammatory properties, and considerable thrombolytic activity. In conclusion, this study provided a new direction and developed a novel multi-functional nano microsphere drug delivery platform for the treatment of DVT.

Immobilization of Urokinase onto Magnetically Directed Micromotors

In this presented work, a new micromotor was prepared for urokinase immobilization. A covalent bond was constructed between the urokinase and the carboxyl groups of the graphene oxide, which is located at the outer layer of micromotors by EDC/NHS chemistry. The inner nickel layer gave magnetic properties to the micromotors and enables them to be separated from the reaction medium with the help of a simple magnet. For promising in vivo applications in the future, these micromotors do not require any fuel for their movement. The structures of the synthesized micromotors were illuminated by SEM and EDX analysis, and the movements of the micromotors were observed under an optical microscope with camera equipment. The immobilization yield of urokinase was found to be 68.07% (0.073 mg/100 µL micromotor solution) using the Bradford protein assay. In addition, to compare the activities of the immobilized and free enzymes, Lineweaver-Burk plots were constructed, and the kinetic parameters were calculated. K_m values for free urokinase and immobilized urokinase were 2.0964 mM and 0.5602 mM, respectively. The maximum velocities of free and immobilized urokinase were found to be 25.25 µmol/min and 30.12 µmol/min, respectively. Also, storage stability profiles of the immobilized and free urokinase were monitored for 40-day incubation at + 4 °C, and the immobilized enzyme has 88% of its initial activity, while the free urokinase demonstrated only 30% of its initial activity. As a result, the experiments were carried out in human commercial serum, and specific activity values for free urokinase and immobilized urokinase were found to be 38.06 and 169.84 µmolmg^-1 min^-1, respectively.

Industrial applications of immobilized nano-biocatalysts

Immobilized enzyme-based catalytic constructs could greatly improve various industrial processes due to their extraordinary catalytic activity and reaction specificity. In recent decades, nano-enzymes, defined as enzyme immobilized on nanomaterials, gained popularity for the enzymes' improved stability, reusability, and ease of separation from the biocatalytic process. Thus, enzymes can be strategically incorporated into nanostructured materials to engineer nano-enzymes, such as nanoporous particles, nanofibers, nanoflowers, nanogels, nanomembranes, metal-organic frameworks, multi-walled or single-walled carbon nanotubes, and nanoparticles with tuned shape and size. Surface-area-to-volume ratio, pore-volume, chemical compositions, electrical charge or conductivity of nanomaterials, protein charge, hydrophobicity, and amino acid composition on protein surface play fundamental roles in the nano-enzyme preparation and catalytic properties. With proper understanding, the optimization of the above-mentioned factors will lead to favorable micro-environments for biocatalysts of industrial relevance. Thus, the application of nano-enzymes promise to further strengthen the advances in catalysis, biotransformation, biosensing, and biomarker discovery. Herein, this review article spotlights recent progress in nano-enzyme development and their possible implementation in different areas, including biomedicine, biosensors, bioremediation of industrial pollutants, biofuel production, textile, leather, detergent, food industries and antifouling.

Biocompatibility pathways and mechanisms for bioactive materials: The bioactivity zone

This essay analyzes the scientific evidence that forms the basis of bioactive materials, covering the fundamental understanding of bioactivity phenomena and correlation with the mechanisms of biocompatibility of biomaterials. This is a detailed assessment of performance in areas such as bone-induction, cell adhesion, immunomodulation, thrombogenicity and antimicrobial behavior. Bioactivity is the modulation of biological activity by characteristics of the interfacial region that incorporates the material surface and the immediate local host tissue. Although the term ‘bioactive material’ is widely used and has a well understood general meaning, it would be useful now to concentrate on this interfacial region, considered as ‘the bioactivity zone’. Bioactivity phenomena are either due to topographical/micromechanical characteristics, or to biologically active species that are presented in the bioactivity zone. Examples of topographical/micromechanical effects are the modulation of the osteoblast – osteoclast balance, nanotopographical regulation of cell adhesion, and bactericidal nanostructures. Regulation of bioactivity by biologically active species include their influence, especially of metal ions, on signaling pathways in bone formation, the role of cell adhesion molecules and bioactive peptides in cell attachment, macrophage polarization by immunoregulatory molecules and antimicrobial peptides. While much experimental data exists to demonstrate the potential of such phenomena, there are considerable barriers to their effective clinical translation. This essay shows that there is solid scientific evidence of the existence of bioactivity mechanisms that are associated with some types of biomaterials, especially when the material is modified in a manner designed to specifically induce that activity.

Study the effect of static magnetic field intensity on drug delivery by magnetic nanoparticles

Employing the magnets in therapy has a long history of treating diseases, and currently new applications such as drug delivery by magnetic nanoparticles are gaining more attention. This research tried to study the effect of static magnetic field intensity on drug delivery by magnetic nanoparticles carrying thrombolytic agents. In this research, Fe₃O₄@SiO₂ nanoparticles carrying streptokinase were applied. The efficiency of thrombolysis and micro-CT-scan images are utilized to study the effect of different magnetic fields (0.1, 0.2, 0.3 and 0.5 T) on thrombolysis. The results confirm that increasing the static magnetic field intensity accelerated the thrombolysis. Increasing the intensity of the magnetic field from 0.1 to 0.3 T leads to an increase in clot dissolution rate from 55 to 89%, respectively. Moreover, micro-CT-scan images revealed that magnetic nanoparticles carrying a thrombolytic agent penetrated deeper into the mesh-like structure of clot as the magnetic field intensities increased, which could lead to further dissolution of the clot.

Fucoidan-functionalized polysaccharide submicroparticles loaded with alteplase for efficient targeted thrombolytic therapy

Intravenous administration of fibrinolytic drugs is the standard treatment of acute thrombotic diseases. However, current fibrinolytics exhibit limited clinical efficacy because of their short plasma half-lives and might trigger hemorrhagic transformations. Therefore, it is mandatory to develop innovative nanomedicine-based solutions for more efficient and safer thrombolysis with biocompatible and biodegradable thrombus-targeted nanocarrier. Herein, fucoidan-functionalized hydrogel polysaccharide submicroparticles with high biocompatibility are elaborated by the inverse miniemulsion/crosslinking method. They are loaded with the gold standard fibrinolytic - alteplase - to direct site-specific fibrinolysis due to nanomolar interactions between fucoidan and P-selectin overexpressed on activated platelets and endothelial cells in the thrombus area. The thrombus targeting properties of these particles are validated in a microfluidic assay containing recombinant P-selectin and activated platelets under arterial and venous blood shear rates as well as in vivo. The experiments on the murine model of acute thromboembolic ischemic stroke support this product's therapeutic efficacy, revealing a faster recanalization rate in the middle cerebral artery than with free alteplase, which reduces post-ischemic cerebral infarct lesions and blood-brain barrier permeability. Altogether, this proof-of-concept study demonstrates the potential of a biomaterial-based targeted nanomedicine for the precise treatment of acute thrombotic events, such as ischemic stroke.

Targeted Thrombolytic Therapy with Metal-Organic-Framework-Derived Carbon Based Platforms with Multimodal Capabilities

A dual-response (near-infrared, alternating magnetic field) multifunctional nanoplatform was developed based on urokinase plasminogen activators (uPA)-loaded metal-organic-framework (MOF)-derived carbon nanomaterials (referred to uPA@CFs below) for thrombolytic therapy. uPA loaded in mesoporous CFs could be released under the action of near-infrared (NIR)-mediated photothermy to achieve superficial thrombolysis. More importantly, with the assistance of alternating magnetic field (AMF), this system could also precisely heat the thrombosis in the deep tissue area. Quantitative experiments proved that the thrombolytic efficiency of this dual-response system at deep venous thrombosis was nearly 6 times than that of NIR alone. This is the first application that MOF-derived carbon nanomaterials in the field of targeted thrombolysis. To our delight, the MOF-derived carbon nanomaterials (CFs) not only maintained the drug-carrying capacity, but also endowed CFs with reliable magnetic targeting ability. More encouragingly, the CFs also showed extraordinary angiogenic performance, thus opening up the prospect of its clinical application.

Thrombolysis Combined Therapy Using CuS@SiO2-PEG/uPA Nanoparticles

Massive hemorrhage caused by the uncontrolled release of thrombolysis drugs is a key issue of thrombolysis therapy in clinical practice. In this study, we report a near-infrared (NIR) light-triggered drug delivery system, i.e., CuS@mSiO₂-PEG (CSP) nanoparticles, for the loading of a thrombolytic drug (urokinase plasminogen activators, uPA). CSP nanoparticles with the CuS nanoparticles as photothermal agents and mesoporous SiO₂ for the loading of uPA were synthesized using a facile hydrothermal method. The CSP core-shell nanoparticles were demonstrated to possess excellent photothermal performance, exhibiting a photothermal conversion efficiency of up to 52.8%. Due to the mesoporous SiO₂ coating, the CSP core-shell nanoparticles exhibited appropriate pore size, high pore volume, and large surface area; thus, they showed great potential to be used as drug carriers. Importantly, the release of uPA from CuS@mSiO₂-PEG/uPA (CSPA) carriers can be promoted by the NIR laser irradiation. The drug loading content of uPA for the as-prepared NIR-triggered drug delivery system was calculated to be 8.2%, and the loading efficiency can be determined to be as high as 89.6%. Due to the excellent photothermal effect of CSP nanocarriers, the NIR-triggered drug delivery system can be used for infrared thermal imaging in vivo. The in vivo thrombolysis assessment demonstrated that the NIR-triggered drug delivery system showed excellent thrombolytic ability under the irradiation of an 808 nm laser, showing the combined therapy for thrombolysis. As far as we know, the CSPA core-shell nanoparticles used as NIR-triggered drug delivery systems for thrombolysis have not been reported.

Synthetic high-density lipoproteins loaded with an antiplatelet drug for efficient inhibition of thrombosis in mice

Antiplatelet agents offer a desirable approach to thrombosis prevention through the reduction of platelet reactivity. However, major bleeding events greatly attenuate the clinical outcomes of most antithrombotic agents. Therefore, the development of safer and more effective strategies to prevent vascular occlusion and avoid bleeding is urgently needed. A reconstituted nanoparticle, synthetic high-density lipoprotein (sHDL), which mimics the native HDL, has been established as clinically safe and is easily manufactured on a large scale. In this study, we propose that the delivery of the antiplatelet drug ML355, a selective inhibitor of 12(S)-lipoxygenase (12-LOX), by sHDL will efficiently inhibit thrombosis by targeting ML355 to the intended site of action, improving the pharmaceutical profile and harnessing the innate antithrombotic efficacy of the sHDL carrier. Our data show that ML355-sHDL exhibits more potent inhibition of thrombus formation in both small arterioles and larger arteries in mice without impairing the normal hemostasis in vivo.

Thrombolytic Agents: Nanocarriers in Controlled Release

Thrombosis is a life-threatening pathological condition in which blood clots form in blood vessels, obstructing or interfering with blood flow. Thrombolytic agents (TAs) are enzymes that can catalyze the conversion of plasminogen to plasmin to dissolve blood clots. The plasmin formed by TAs breaks down fibrin clots into soluble fibrin that finally dissolves thrombi. Several TAs have been developed to treat various thromboembolic diseases, such as pulmonary embolisms, acute myocardial infarction, deep vein thrombosis, and extensive coronary emboli. However, systemic TA administration can trigger non-specific activation that can increase the incidence of bleeding. Moreover, protein-based TAs are rapidly inactivated upon injection resulting in the need for large doses. To overcome these limitations, various types of nanocarriers have been introduced that enhance the pharmacokinetic effects by protecting the TA from the biological environment and targeting the release into coagulation. The nanocarriers show increasing half-life, reducing side effects, and improving overall TA efficacy. In this work, the recent advances in various types of TAs and nanocarriers are thoroughly reviewed. Various types of nanocarriers, including lipid-based, polymer-based, and metal-based nanoparticles are described, for the targeted delivery of TAs. This work also provides insights into issues related to the future of TA development and successful clinical translation.

Intrinsic Biotaxi Solution Based on Blood Cell Membrane Cloaking Enables Fullerenol Thrombolysis In Vivo

We report the construction of blood cell membrane cloaked mesoporous silica nanoparticles for delivery of nanoparticles [fullerenols (Fols)] with fibrinolysis activity which endows the active Fol with successful thrombolysis effect in vivo. In vitro, Fols present excellent fibrinolysis activity, and the Fol with the best fibrinolysis activity is screened based on the correlation between Fols' structure and their fibrinolysis activity. However, the thrombolytic effect in vivo is not satisfactory. To rectify the unsatisfactory situation and avoid the exogenous stimuli, a natural blood cell membrane cloaking strategy with loading the active Fol is chosen to explore as a novel thrombolysis drug. After cloaking, the therapeutic platform prolongs blood circulation time and enhances the targeting effect. Interestingly, compared with platelet membrane cloaking, red blood cell (RBC) membrane cloaking demonstrates stronger affinity with fibrin and more enrichment at the thrombus site. The Fol with RBC cloaking shows quick and efficient thrombolysis efficacy in vivo with less bleeding risk, more excellent blood compatibility, and better biosafety when compared with the clinical drug urokinase (UK). These findings not only validate the blood cell membrane cloaking strategy as an effective platform for Fol delivery on thrombolysis treatment, but also hold a great promising solution for other active nanoparticle deliveries in vivo.

Hyperthermia-triggered UK release nanovectors for deep venous thrombosis therapy

Deep vein thrombosis (DVT) is a common and lethal complication of surgery.

Near-Infrared Light Activated Thermosensitive Ion Channel to Remotely Control Transgene System for Thrombolysis Therapy

Current antithrombotic therapeutic strategies often suffer from severe post-thrombotic syndromes (PTS), inconvenient daily subcutaneous injections for a long time and short circulation times accompanied by a dose-dependent risk of intracranial hemorrhage. Aiming at noninvasive, on-demand, and sustained antithrombotic therapy, a new thrombolysis approach based on the transgene system has been developed to remotely and precisely control the expression of urokinase plasminogen activator (uPA) by bioengineered cells for antithrombotic therapy both in vitro and in vivo. In this design, the near-infrared (NIR) light could activate the expression of the thermosensitive TRPV1 channel in response to photothermal responsive nanotransducers to trigger the synthetic signaling pathway to secret uPA. By encapsulating bioengineered cells in injectable hydrogel to ensure long-term survival and convenience for injection, the engineered cells could noninvasively and precisely control the production of uPA protein in situ via an NIR laser to significantly enhance the thrombolysis therapeutic effects by spatiotemporally controlling the local temperature, in both the microfluidic blood circulation mimic and the murine tail thrombus model. This novel thrombolysis approach could overcome some key limitations that are associated with conventional antithrombotic therapy, thus opening a new direction for developing remotely and precisely controllable continuous thrombolysis through artificially designed signaling.

Targeted thrombolysis by using c-RGD-modified N,N,N-Trimethyl Chitosan nanoparticles loaded with lumbrokinase

Lumbrokinase (LK) has strong fibrinolytic and thrombolytic activities, but it has a short half-life, can be easily inactivated, and may cause hemorrhage as a side effect. This study develops a potential thrombolytic therapy by fabricating N,N,N-Trimethyl Chitosan (TMC) nanoparticles modified with the cyclic Arg-Gly-Asp-Phe-Lys peptide (c-RGD) and loaded with LK (i.e. c-RGD-LK-NPs). The binding of c-RGD to platelet membrane GPIIb/IIIa receptors is expected to enable targeted delivery of the c-RGD-conjugated TMC to the thrombus. The synthesized c-RGD-LK-NPs had a mean particle size of 232.0 nm, zeta potential of 19.8 mV, entrapment efficiency of 52.7% ± 2.5%, and loading efficiency of 17.4% ± 0.65%. Transmission electron microscopy showed that they were generally spherical. The c-RGD-LK-NPs gave a cumulative in vitro LK release of 80.6% over 8 h, and the activity of LK was close to 80%, indicating that the nanoparticles protected the activity of LK. In vitro blood clot lysis assays were carried out and in vivo thrombolysis effect was tested in Sprague-Dawley rats carotid artery thrombus model. In all cases, the c-RGD-LK-NPs showed superior performance compared with the free LK and the unmodified TMC nanoparticles loaded with LK. The c-RGD-LK-NPs reagent is expected to be potentially useful in treating thromboembolic diseases.

Thrombolytic therapy based on fucoidan-functionalized polymer nanoparticles targeting P-selectin

Injection of recombinant tissue plasminogen activator (rt-PA) is the standard drug treatment for thrombolysis. However, rt-PA shows risk of hemorrhages and limited efficiency even at high doses. Polysaccharide-poly(isobutylcyanoacrylate) nanoparticles functionalized with fucoidan and loaded with rt-PA were designed to accumulate on the thrombus. Fucoidan has a nanomolar affinity for the P-selectin expressed by activated platelets in the thrombus. Solid spherical fluorescent nanoparticles with a hydrodynamic diameter of 136 ± 4 nm were synthesized by redox radical emulsion polymerization. The clinical rt-PA formulation was successfully loaded by adsorption on aminated nanoparticles and able to be released in vitro. We validated the in vitro fibrinolytic activity and binding under flow to both recombinant P-selectin and activated platelet aggregates. The thrombolysis efficiency was demonstrated in a mouse model of venous thrombosis by monitoring the platelet density with intravital microscopy. This study supports the hypothesis that fucoidan-nanoparticles improve the rt-PA efficiency. This work establishes the proof-of-concept of fucoidan-based carriers for targeted thrombolysis.

The Future of Nanoparticle-Directed Venous Therapy

Nanoparticles, structures of less than 200 nm capable of delivering pharmacotherapeutics to sites of disease, have shown great promise for the treatment of many disease states. While no nanoparticle therapies for deep vein thrombosis are currently approved by the Food and Drug Administration, many of the unique features of these therapies have the potential to treat both deep vein thrombosis and its most significant sequela, postthrombotic syndrome, while limiting the hemorrhagic complications of current antithrombotic therapies. Nanoparticles are complex structures with several important variables that must be considered to engineer effective therapies. This article will review the structure and engineering of nanoparticles, as well as promising molecular targets for future investigation.

An In Vitro Thrombolysis Study Using a Mixture of Fast-Acting and Slower Release Microspheres

PURPOSE

To test the hypothesis that a mixture combining fast and slower release rate microspheres can restore blood flow rapidly and prevent formation of another blockage in thrombolysis.

METHODS

We used polyethylene glycol (PEG) microspheres which provide the release of the encapsulated streptokinase (SK) on the scale of minutes, and Eudragit FS30D (Eud), a polymethacrylate polymer, for development of delayed release microspheres which were desirable to prevent a putative second thrombus. Eud microspheres were coated with chitosan (CS) to further extend half-life. Experiments included the development, characterization of Eud/SK and CS-Eud/SK microspheres, and in vitro thrombolytic studies of the mixtures of PEG/SK and Eud /SK microspheres and of PEG/SK and CS-Eud/SK microspheres.

RESULTS

CS-Eud/SK microspheres have slightly lower encapsulation efficiency, reduced activity of SK, and a much slower release of SK when compared with microspheres of Eud/SK microspheres. Counter-intuitively, slower release leads to faster thrombolysis after reocclusion as a result of greater retention of agent and the mechanism of distributed intraclot thrombolysis.

CONCLUSIONS

A mixture of PEG/SK and CS-Eud/SK microspheres could break up the blood clot rapidly while providing clot-lytic efficacy in prevention of a second blockage up to 4 h.

Nanomedicine as a strategy to fight thrombotic diseases

This review highlights the preclinical and clinical research based on the use of nano- and micro-carriers in thrombolytic drug delivery. Ischemic heart and stroke caused by thrombosis are the main causes of death in the world. Because of their inactivation in the blood, high doses of thrombolytics are administered to patients, increasing the risk of intracranial hemorrhage. Preclinical research conducted with lipid, polymer or magnetic nanoparticles loaded with thrombolytic drugs showed an enhancement of thrombolysis and a reduction of undesirable side effects. Targeted nanocarriers exhibited an increased accumulation into clot. Clinical trials were already conducted with lipid-based microbubbles combined with ultrasound and thrombolytic drug and showed thrombolysis improvement. Future validation of nanosystems is awaited in clinic. This research opens new strategies for the management of thrombotic diseases.

To dissolve a thrombus, thrombolytic drugs are administered, but they are rapidly inactivated in the blood. High amounts are thus injected to patients with the risk to develop intracranial hemorrhages. Nanocarriers and microbubbles have been tested in preclinical models to deliver thrombolytic drugs. These systems have the advantage to protect the drug from the degradation. In clinical trials, galactose and lipid-based microbubbles associated to ultrasound and thrombolytic drugs showed an enhancement of thrombolysis. Other systems are also expected with new drugs combined or not with endovascular intervention to treat ischemic heart or stroke.

Thrombosis: Novel nanomedical concepts of diagnosis and treatment

Intravascular thrombosis, a critical pathophysiological feature of many cardiovascular disorders, leads to the formation of life-threatening obstructive blood clots within the vessels. Rapid recanalization of occluded vessels is essential for the patients’ outcome, but the currently available systemic fibrinolytic therapy is associated with low efficacy and tremendous side effects. Additionally, many patients are ineligible for systemic thrombolytic therapy, either due to delayed admission to the hospital after symptom onset, or because of recent surgery, or bleeding. In order to improve the treatment efficacy and to limit the risk of hemorrhagic complications, both precise imaging of the affected vascular regions, and the localized application of fibrinolytic agents, are required. Recent years have brought about considerable advances in nanomedical approaches to thrombosis. Although these thrombus-targeting imaging agents and nanotherapies are not yet implemented in humans, substantial amount of successful in vivo applications have been reported, including animal models of stroke, acute arterial thrombosis, and pulmonary embolism. It is evident that the future progress in diagnosis and treatment of thrombosis will be closely bound with the development of novel nanotechnology-based strategies. This Editorial focuses on the recently reported approaches, which hold a great promise for personalized, disease-targeted treatment and reduced side effects in the patients suffering from this life-threatening condition.

Visible Thrombolysis Acceleration of a Nanomachine Powered by Light-Driving F0F1-ATPase Motor

We report on thrombolysis acceleration of a nanomachine powered by light-driving δ-subunit-free F0F1-ATPase motor. It is composed of a mechanical device, locating device, energy storage device, and propeller. The rotory δ-subunit-free F0F1-ATPase motor acts as a mechanical device, which was obtained by reconstructing an original chromatophore extracted from Rhodospirillum rubrum. We found that the bioactivity of the F0F1-ATPase motor improved greatly after reconstruction. The zeta potential of the nanomachine is about -23.4 mV. Cytotoxicity induced by the nanomachine was measured using cell counting kit (CCK)-8 assay. The A549 cells incubated with different fractional concentrations of the nanomachine within 48 h did not show obvious cytotoxicity. The locating device helps the nanomachine bind to the thrombi. Energy was easily stored by exposing the nanomachine to 600-nm-wavelength irradiation, which promoted activity of the motor. The rotation of the long propeller accelerated thrombolysis of a blood clot in vitro in the presence of urokinase (UK). This result was based on visual inspection and confirmed by a series of tests.