Localized Light-Au-Hyperthermia Treatment for Precise, Rapid, and Drug-Free Blood Clot Lysis

Phosphatidylcholine Liposome Accelerated Platinum Nanomachines (PLANEs) With Enhanced Penetration Capability for Thrombus Mechanotherapy

Thrombotic cardiovascular diseases remain the leading cause of mortality worldwide. However, current thrombolytic therapeutics suffer from limited efficacy and a high risk of severe bleeding. Here, a phosphatidylcholine liposome accelerated platinum nanomachine (PLANE) for thrombus mechanotherapy is designed, constructed by encapsulating platinum nanomotors within isotropic, lubricating phosphatidylcholine (PC) liposomes. The precisely engineered PLANE exhibits superior lubricity and linear motion. Under laser irradiation and hydrogen peroxide treatment, PLANEs achieve significantly higher velocities than conventional platinum nanomotors, facilitating deep penetration into the thrombi. Further functionalization with thrombus-targeting peptides enables the cPLANEs to selectively accumulate at the thrombotic sites in vivo, demonstrating excellent thrombolytic efficacy. This work presents a novel surface modification strategy for optimizing the motion behavior of platinum nanomotors, offering a promising non-pharmaceutic approach for thrombotic disease treatment.

Trident-inspired fucoidan-based armor-piercing microcapsule for programmed acute pulmonary embolism treatment

Pulmonary embolism remains the third leading cause of human mortality after malignant tumors and myocardial infarction. Commonly available thrombolytic therapeutic agents suffer from the limitations of very short half-life, inadequate targeting, limited clot penetration, and a propensity for severe bleeding. Inspired by the trident, we developed the armor-piercing microcapsule (MC), fucoidan-urokinase-S-nitrosoglutathione-polydopamine@MC (FUGP@MC), which exhibited a triple combination of photothermal, mechanical and pharmacological thrombolysis for the therapeutic treatment of acute pulmonary embolism (APE). Briefly, the outermost fucoidan layer was utilized for targeting to the APE area. Programmed APE treatment was triggered by near-infrared (NIR) light irradiation. Photothermal thrombolytic therapy was carried out by photothermal conversion of polydopamine. The photothermal conversion broke the S-nitroso bond in S-nitrosoglutathione (GSNO) and produced large amounts of nitric oxide (NO) for mechanical thrombolysis, which subsequently disrupted the interfacial structure of microcapsule to stimulate the release of the urokinase (UK), leading to a triple synergistic thrombolytic effect. The results demonstrated that the embolization residual rate of FUGP@MC (contained ≈ 1452.5 IU/kg UK) group was significantly lower than that of UK (10,000 IU/kg) group (6.35 % VS 16.78 %). Remarkably, FUGP@MC demonstrated a reliable in vivo biosafety proficiency. In summary, trident-inspired armor-piercing microcapsule FUGP@MC reveals a potential avenue for advancing pulmonary embolism therapeutics and promises to be a safer alternative candidate to current drug approaches.

Advances in Nano-Functional Materials in Targeted Thrombolytic Drug Delivery

Thrombotic disease has been listed as the third most fatal vascular disease in the world. After decades of development, clinical thrombolytic drugs still cannot avoid the occurrence of adverse reactions such as bleeding. A number of studies have shown that the application of various nano-functional materials in thrombus-targeted drug delivery, combined with external stimuli, such as magnetic, near-infrared light, ultrasound, etc., enrich the drugs in the thrombus site and use the properties of nano-functional materials for collaborative thrombolysis, which can effectively reduce adverse reactions such as bleeding and improve thrombolysis efficiency. In this paper, the research progress of organic nanomaterials, inorganic nanomaterials, and biomimetic nanomaterials for drug delivery is briefly reviewed.

Biomimetic Nanoplatelets to Target Delivery Hirudin for Site-Specific Photothermal/Photodynamic Thrombolysis and Preventing Venous Thrombus Formation

Due to the high recurrence rate and mortality of venous thrombosis, there is an urgent need for research on antithrombotic strategies. Because of the short half-life, poor targeting capabilities, bleeding complications, and neurotoxic effects of conventional pharmacological thrombolysis methods, it is essential to develop an alternative strategy to noninvasive thrombolysis and decrease the recurrence rate of venous thrombosis. A platelet-mimetic porphyrin-based covalent organic framework-engineered melanin nanoplatform, to target delivery of hirudin to the vein thrombus site for noninvasive thrombolysis and effective anticoagulation, is first proposed. Owing to the thrombus-hosting properties of platelet membranes, the nanoplatform can target the thrombus site and then activate hyperthermia and reactive oxygen species for thrombolysis under near-infrared light irradiation. The photothermal therapy/photodynamic therapy combo can substantially improve the effectiveness (85.7%) of thrombolysis and prevent secondary embolism of larger fragments. Afterward, the highly loaded (97%) and slow-release hirudin (14 days) are effective in preventing the recurrence of blood clots without the danger of thrombocytopenia. The described biomimetic nanostructures offer a promising option for improving the efficacy of thrombolytic therapy and reducing the risk of bleeding complications in thrombus associated diseases.

A Synergistic and Efficient Thrombolytic Nanoplatform: A Mechanical Method of Blasting Combined with Thrombolytic Drugs

BACKGROUND AND OBJECTIVE

Thrombosis is a common disease that poses a great threat to life and health. Most thrombolytic effects of traditional treatments or nanomedicine are not efficient or safe enough. Therefore, we designed a nanoparticle (NP) with a combination of a phase transition material and thrombolytic drugs for efficient and safe thrombolysis.

METHODS

A thrombus fibrin-targeted and phase transition NP was designed and contained perfluorohexane (PFH) and the thrombolytic drug rtPA core, with CREKA polypeptides attached to the shell of the PLGA NPs. Characterization of the phase transition and ultrasound imaging of the NPs was carried out under low-intensity focused ultrasound (LIFU). LIFU-responsive drug release in vitro was also explored. Under the synergistic effect of PFH and rtPA, the efficient thrombolysis ability of the NPs was studied in vitro and in vivo. In vivo monitoring of thrombosis and biosafety were also verified.

RESULTS

The PPrC NPs had good ultrasound imaging ability under LIFU irradiation and were related to the phase transition characteristics of the NPs. CREKA polypeptides can effectively increase the aggregation of the NPs on thrombi. Under static and dynamic conditions in vitro, the "liquid to gas" transformation effect of PFH can perform the destruction function of the excavator at the thrombus site and promote the specific release of rtPA, and the subsequent rtPA drug thrombolysis can further fully dissolve the thrombus. In vivo experiments showed that the NPs can monitor the formation of thrombi and have good thrombolytic effects, with significantly reduced bleeding side effects. The biochemical indexes of the rats were within normal limits after treatment.

CONCLUSION

PPrC NPs loaded with PFH and rtPA combining a mechanical way of blasting with thrombolytic drugs may be a promising new and reliable approach for thrombus monitoring and treatment.

Dual drive mode polydopamine nanomotors for continuous treatment of an inferior vena cava thrombus

It is of great significance to find effective thrombolytic treatments due to the harm caused by thrombosis to human health. Based on the formation mechanism and complex microenvironment of a thrombus, polydopamine nanomotors (PDANMs) modified by the peptide of Arg-Gly-Asp (RGD) and loaded with urokinase (UK) were designed and prepared. A polydopamine (PDA) substrate has a good photothermal conversion effect. Under near-infrared (NIR) light irradiation, it can not only perform photothermal therapy (PTT) on thrombus, but also provide the driving force of PDANMs. Thrombolytic drug UK was loaded in the mesoporous structure of the PDA substrate and can be released at the thrombus site for drug therapy. The modified RGD can target the thrombus site, moreover, benefiting from the guanidine group of L-arginine in the peptide chain, and RGD can interact with reactive oxygen species (ROS) in the thrombus microenvironment to produce nitric oxide (NO). NO not only propelled the movement of nanomotors, but also promoted the growth of vascular endothelial cells to repair damaged blood vessels. The experimental results show that NIR and NO can provide dual driving sources for the nanosystem to achieve continuous and deep penetration of the drug-loaded nanomotors at the thrombus site, while realizing the photothermal and drug synergistic therapy to enhance the therapeutic effect and promote the growth of vascular endothelium cells. This kind of thrombus treatment strategy based on nanomotor drug delivery systems will provide good technical support for the clinical treatment of inferior vena cava thrombus.

Thrombus-specific theranostic nanocomposite for codelivery of thrombolytic drug, algae-derived anticoagulant and NIR fluorescent contrast agent

Thrombolysis is a standard treatment for rapidly restoring blood flow. However, the application of urokinase-type plasminogen activator (Uk) in clinical therapy is limited due to its nonspecific distribution and inadequate therapeutic accumulation. Precise thrombus imaging and site-specific drug delivery can enhance the diagnostic and therapeutic efficacy for thrombosis. Accordingly, we developed a P-selectin-specific, photothermal theranostic nanocomposite for thrombus-targeted codelivery of Uk and indocyanine green (ICG, a contrast agent for near-infrared (NIR) fluorescence imaging). We evaluated its capabilities for thrombus imaging and enzyme/hyperthermia combined thrombolytic therapy. Mesoporous silica-coated gold nanorods (Si-AuNRs) were functionalized with an arginine-rich peptide to create an organic template for the adsorption of ICG and fucoidan (Fu), an algae-derived anticoagulant. Uk was loaded into the SiO₂ pores of the Si-AuNRs through the formation of a Fu-Uk-ICG complex on the peptide-functionalized template. The Fu-Uk/ICG@SiAu NRs nanocomposite increased the photostability of ICG and improved its targeting/accumulation at blood clot sites with a strong NIR fluorescence intensity for precise thrombus imaging. Furthermore, ICG incorporated into the nanocomposite enhanced the photothermal effect of Si-AuNRs. Fu, as a P-selectin-targeting ligand, enabled the nanocomposite to target a thrombus site where platelets were activated. The nanocomposite enabled a faster release of Uk for rapid clearing of blood clots and a slower release of Fu for longer lasting prevention of thrombosis regeneration. The nanocomposite with multiple functions, including thrombus-targeting drug delivery, photothermal thrombolysis, and NIR fluorescence imaging, is thus an advanced theranostic platform for thrombolytic therapy with reduced hemorrhaging risk and enhanced imaging/thrombolysis efficiency. STATEMENT OF SIGNIFICANCE: Herein, for the first time, a P-selectin specific, photothermal theranostic nanocomposite for thrombus-targeted co-delivery of urokinase and NIR fluorescence contrast agent indocyanine green (ICG) was developed. We evaluated the potential of this theranostic nanocomposite for thrombus imaging and enzyme/hyperthermia combined thrombolytic therapy. The nanocomposite showed multiple functions including thrombus targeting and imaging, and photothermal thrombolysis. Besides, it allowed faster release of the thrombolytic urokinase for rapidly clearing blood clots and slower release of a brown algae-derived anticoagulant fucoidan (also acting as a P-selectin ligand) for prevention of thrombosis regeneration. The nanocomposite is thus a new and advanced theranostic platform for targeted thrombolytic therapy.

Near-infrared light-responsive liposomes for protein delivery: Towards bleeding-free photothermally-assisted thrombolysis

Smart drug delivery systems represent state-of-the-art approaches for targeted therapy of life-threatening diseases such as cancer and cardiovascular diseases. Stimuli-responsive on-demand release of therapeutic agents at the diseased site can significantly limit serious adverse effects. In this study, we engineered a near-infrared (NIR) light-responsive liposomal gold nanorod-containing platform for on-demand delivery of proteins using a hybrid formulation of ultrasmall gold nanorods (AuNRs), thermosensitive phospholipid (DPPC) and non-ionic surfactant (Brij58). In light-triggered release optimization studies, 55.6% (± 4.8) of a FITC-labelled model protein, ovalbumin (MW 45 kDa) was released in 15 min upon NIR irradiation (785 nm, 1.35 W/cm² for 5 min). This platform was then utilized to test on-demand delivery of urokinase-plasminogen activator (uPA) for bleeding-free photothermally-assisted thrombolysis, where the photothermal effect of AuNRs would synergize with the released uPA in clot lysis. Urokinase light-responsive liposomes showed 80.7% (± 4.5) lysis of an in vitro halo-clot model in 30 min following NIR irradiation (785 nm, 1.35 W/cm² for 5 min) compared to 36.3% (± 4.4) and 15.5% (± 5.5) clot lysis from equivalent free uPA and non-irradiated liposomes respectively. These results show the potential of low-dose, site-specific thrombolysis via the combination of light-triggered delivery/release of uPA from liposomes combined with photothermal thrombolytic effects from gold nanorods. In conclusion, newly engineered, gold nanorod-based, NIR light-responsive liposomes represent a promising drug delivery system for site-directed, photothermally-stimulated therapeutic protein release.

Human hair derived uPA loaded capsules with dual near-infrared (I and II biowindows) laser responsive capabilities for multi-effective thrombolysis therapy

Problems such as massive hemorrhage caused by uncontrolled drug dosage are the main significant obstacles in clinical thrombolytic therapy, which are prominently due to the lack of targeting and controlled release ability of efficient thrombolytic drug systems. In recent years, our team demonstrated that the photothermal effect can facilitate the thrombolytic effect of urokinase plasminogen activator (uPA). However, conventional photothermal agents are relatively expensive or contain heavy metals. If drug delivery systems with low toxicity, minimized heavy metal elements and easy accessibility (preferably provided by human self) can be developed, they will be of value in the future related applications. Herein, uPA-loaded human black hair derived nanoparticles with gelatin capsules (uPA@HBHNP@GNCs) were applied for the first time as a thrombolytic system. Upon irradiation by near-infrared I window (NIR-I) laser or II window (NIR-II) laser, the photothermal effect of HBHNP was triggered to promote the melting of the gelatin encapsulated around the outer layer, thereby realizing the targeted release of uPA. The in vitro and in vivo experiments demonstrated that the deep response to NIR (especially II window) of this system exhibited a satisfactory thrombolytic effect with ideal biosafety. Briefly, the proposed hair derived drug delivery system has the characteristics of human source, low cost, minimum heavy metal components, deep response to NIR (II window) laser, and good biocompatibility, which is expected to be expanded to the treatment for some diseases, even in deep tissue areas.

Thrombin-responsive engineered nanoexcavator with full-thickness infiltration capability for pharmaceutical-free deep venous thrombosis theranostics

Although nanotechnology has shown great promise for treating multiple vascular diseases in recent years, simultaneous noninvasive detection and efficient dissolution of deep venous thrombosis (DVT) still remains challenging. In particular, long blockage areas and large thrombus thicknesses in DVT cause enormous difficulties for site-specific deep-seated thrombus theranostics. Therefore, based on the unique components of DVT, the novel concept of a thrombin-responsive full-thickness infiltration nonpharmaceutical nanoplatform for DVT theranostics is proposed here. The penetration depth is innovatively enhanced with efficient targeting and accumulation in the whole thrombi. Herein, we report a thrombin-responsive phase-transition liposome incorporating a liquid perfluoropentane (PFP) core and modified with two binding peptides, activatable cell-penetrating peptide (ACPP) and fibrin-binding ligand (FTP), which contribute to efficient liposome targeting and accumulation within the thrombi. This targeted nanoplatform is constructed to dig out the thrombus with the assistance of low-intensity focused ultrasound (LIFU), performing the destructive function of an excavator via an acoustic droplet vaporization effect (acting as a "nanoexcavator" system), which can activate and vaporize into microbubbles to enhance LIFU efficacy. The resulting microbubbles enable real-time monitoring of the therapeutic process with ultrasound imaging and high performance photoacoustic imaging after loading DIR. This non-invasive nonpharmaceutical thrombolytic strategy is an improvement over existing clinical methods without systemic side effects.

Nano-Medicine for Thrombosis: A Precise Diagnosis and Treatment Strategy

Thrombosis is a global health issue and one of the leading factors of death. However, its diagnosis has been limited to the late stages, and its therapeutic window is too narrow to provide reasonable and effective treatment. In addition, clinical thrombolytics suffer from a short half-life, allergic reactions, inactivation, and unwanted tissue hemorrhage. Nano-medicines have gained extensive attention in diagnosis, drug delivery, and photo/sound/magnetic-theranostics due to their convertible properties. Furthermore, diagnosis and treatment of thrombosis using nano-medicines have also been widely studied. This review summarizes the recent advances in this area, which revealed six types of nanoparticle approaches: (1) in vitro diagnostic kits using "synthetic biomarkers"; (2) in vivo imaging using nano-contrast agents; (3) targeted drug delivery systems using artificial nanoparticles; (4) microenvironment responsive drug delivery systems; (5) drug delivery systems using biological nanostructures; and (6) treatments with external irradiation. The investigations of nano-medicines are believed to be of great significance, and some of the advanced drug delivery systems show potential applications in clinical theranotics.