Accelerating thrombolysis using a precision and clot-penetrating drug delivery strategy by nanoparticle-shelled microbubbles

QCM Sensing the Motion of Magnetic Particles: Principle and Signal Acquisition

The traditional quartz crystal microbalance (QCM) technology is primarily used for measuring load mass and requires the load to be in a static state, making it difficult to capture particle motion under the action of external force fields. This study to overcome the constraints of traditional QCM technology by proposing the use of QCM to detect particle motion in liquid loads. This work delves into the principle of QCM sensing particle motion in liquid loads and presents sensing signal models. By investigating the motion mechanism of magnetic particles driven by a magnetic field and generating controllable particle motion, the modulation effect of particle motion on QCM vibration is demonstrated. Experimental results show that particle motion influences the surface strain of the QCM through the liquid medium, modulating the thickness-shear vibration of the QCM. Consequently, particle motion signals can be obtained from the QCM output. Compared to traditional QCM methods that detect static loads, sensing particle motion enables higher sensitivity and stability in detecting parameters (including mass) and allows for the simultaneous detection of multiple load parameters. This study aims to overcome the limitations of traditional QCM technology by proposing a novel approach for detecting particle motion, not only enabling the simultaneous detection of multiple characteristics of the load but also significantly improving detection performance.

Rapid synergistic thrombolysis of ischemic stroke guided by high-resolution and high-speed photoacoustic cerebrovascular imaging

Thrombosis is the major cause of ischemic stroke and poses a serious health burden globally. Current thrombolytic strategies, such as systematic administration of recombinant human tissue plasminogen activator (rt-PA), are challenged by limited thrombolysis efficiency due to low targeting ability and a short plasma half-life. Here, we report a rapid synergistic strategy that integrates sonothrombolysis and rt-PA mediated pharmacological thrombolysis to achieve accurate and efficient treatment of ischemic stroke. The strategy (PLPA@PFP) uses a platelet-biomimetic membrane as a carrier to deliver both perfluoropentane (PFP) and rt-PA, prolonging half-life and effectively accumulating at the thrombus within 0.5 hours. Upon exposure to focused ultrasound, PFP-based cavitation effects significantly enhance thrombus breakdown and rt-PA penetration, enabling synergistic sono/pharmacological thrombolysis both in vitro and in vivo. High-resolution photoacoustic (PA) imaging provides direct assessment of vascular reperfusion following therapeutic intervention in a murine model of ischemic stroke, offering important guidance for clinical treatment.

Potassium Ferric Oxalate Nanoparticles Prevent Human Blood Clotting and Thrombosis in a Mouse Model

Blood clots create occlusions in the veins and arteries, which leads to pernicious effects. Here, the anticoagulation properties of potassium ferric oxalate nanoparticles (KFeOx-NPs) in human blood were demonstrated for blood clot management. The mechanism involves the chelation of calcium ions from the blood by oxalate present in the KFeOx-NPs. Various commercial assays were used to determine the clotting time for the KFeOx-NPs. Potassium is essential for the overall health of blood vessels and the heart. We used animal models to show toxicity and biodistribution profiles and determine safety and efficacy. Intravenously injected KFeOx-NPs increased clotting time and thrombosis prevention in a mouse model, confirmed by ultrasound and the power Doppler images. Coating catheters with KFeOx-NPs prevents clot formation with reduced protein attachment when incubated with blood, enhancing blood flow properties. In biological applications, KFeOx-NPs may improve the long-term prevention of blood clot formation and enhance the efficiency of medical devices.

Enzyme-Based Anti-Inflammatory Therapeutics for Inflammatory Diseases

Inflammation is a multifaceted biological response of the immune system against various harmful stimuli, including pathogens (such as bacteria and viruses), cellular damage, toxins, and natural/synthetic irritants. This protective mechanism is essential for eliminating the cause of injury, removing damaged cells, and initiating the repair process. While inflammation is a fundamental component of the body's defense and healing process, its dysregulation can lead to pathological consequences, contributing to various acute and chronic diseases, such as autoimmune disorders, cancer, metabolic syndromes, cardiovascular diseases, neurodegenerative conditions, and other systemic complications. Generally, non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids, disease-modifying anti-rheumatic drugs (DMARDs), antihistamines, biologics, and colchicine are used as pharmacological agents in the management of inflammatory diseases. However, these conventional treatments often have limitations, including adverse side effects, long-term toxicity, and drug resistance. In contrast, enzyme-based therapeutics have emerged as a promising alternative due to their high specificity, catalytic efficiency, and ability to modulate inflammatory pathways with reduced side effects. These enzymes function by scavenging reactive oxygen species (ROS), inhibiting cytokine transcription, degrading circulating cytokines, and blocking cytokine release by targeting exocytosis-related receptors. Additionally, their role in tissue repair and regeneration further enhances their therapeutic potential. Most natural anti-inflammatory enzymes belong to the oxidoreductase class, including catalase and superoxide dismutase, as well as hydrolases such as trypsin, chymotrypsin, nattokinase, bromelain, papain, serratiopeptidase, collagenase, hyaluronidase, and lysozyme. Engineered enzymes, such as Tobacco Etch Virus (TEV) protease and botulinum neurotoxin type A (BoNT/A), have also demonstrated significant potential in targeted anti-inflammatory therapies. Recent advancements in enzyme engineering, nanotechnology-based enzyme delivery, and biopharmaceutical formulations have further expanded their applicability in treating inflammatory diseases. This review provides a comprehensive overview of both natural and engineered enzymes, along with their formulations, used as anti-inflammatory therapeutics. It highlights improvements in stability, efficacy, and specificity, as well as minimized immunogenicity, while discussing their mechanisms of action and clinical applications and potential future developments in enzyme-based biomedical therapeutics.

Rapid Blood Clot Removal via Remote Delamination and Magnetization of Clot Debris

Micro/nano-scale robotic devices are emerging as a cutting-edge approach for precision intravascular therapies, offering the potential for highly targeted drug delivery. While employing micro/nanorobotics for stroke treatment is a promising strategy due to its ability to localize therapy and minimize drug dosage, current methods require prolonged treatment durations, increasing the risk of nerve tissue necrosis from extended hypoxia. Here a programmable colloidal microswarm capable of rapidly detaching blood clots from the vessel wall is developed, enabling swift recanalization without the need for complete clot degradation. More importantly, the detached clot debris, despite their random shapes, functions as magnetic "debris-robots" and can be efficiently propelled through helical swimming within flowing vessels, followed by retrieval using catheter suction. The entire process-including catheter delivery, controlled locomotion, clot detachment, and retrieval-can be completed in approximately half an hour, significantly saving time compared to the critical "Golden 6 hours" window for stroke treatment. This retrieval procedure greatly minimizes nanoparticle exposure in the bloodstream and lowers the risk of secondary clotting in distal vessels, marking a significant advancement in robotic-assisted thrombolysis.

Thrombus Boring Microrobot Prepared by an Integrated Phase Separation and Interfacial Self-Assembly Process Toward Thrombolysis

The pathological formation of thrombi is the primary etiological factor of acute cardiovascular and cerebrovascular diseases, accounting for one-quarter of global fatalities. Traditional thrombolytic drugs are constrained by short half-life, low utilization, and severe complications. Inspired by the tunnel boring machine to excavate strata into small rocks, we report urokinase plasminogen activator (uPA)-modified thrombus boring microrobots (uTBMs), prepared by a one-step integrated phase separation and interfacial self-assembly process, for effective thrombolysis. The uTBMs are composed of microspheres capped with dual-layered structures of magnetic nanoparticles (MNPs) and cilia nanostructures. In situ observation reveals the integrated phase separation and interfacial self-assembly process of the uTBM within an emulsion droplet. The capped layer of MNPs allows for controllable motion and rotation behavior under the manipulation of a remote magnetic field. The uPA-modified cilia nanostructures grasp and degrade the fibrin network, synergizing with the uTBMs rotation to mechanically excavate blood cells from thrombus individually, achieving ∼8.5-fold higher thrombolytic efficacy than uPA alone. This research demonstrates the feasibility of controllably fabricating and modifying complex-structured microrobots via the simple process toward potential thrombus therapy.

Breaking the Limitation of Laminar Flow in Thrombolytic Therapy with Reconfigurable Vortex-Like Nanobot Swarms

Laminar blood flow represents the normal physiological state of blood circulation, but it also acts as a natural physiological barrier for the effective diffusion of drugs to the lesion site. Here, we report a bioinspired strategy in which reconfigurable vortex-like swarms of magnetic swimming nanobots actively disrupt the laminar flow to deliver drugs in a manner similar to how bacteria seek food. The drug was released from the cavity of biodegradable, submicron pentosan flask-like nanobots, aggregates as the dynamic rotating drug fluid under a rotating magnetic field. The vortex-like nanobot swarm successfully overcame the laminar barrier near the thrombus in a rat inferior vena cava stenosis thrombosis model, which was observed by ultrasound blood flow imaging. Furthermore, the clinical feasibility of nanobots swarm for enhancing thrombolytic efficacy through drug aggregation after breaking the laminar flow was further confirmed in a rat deep vein thrombosis model. This bionic active targeting approach overcomes the laminar flow barrier and restricts the release of drugs by the swarm-induced vortex fluid to facilitate targeted drug delivery, which is expected to be an innovative method to enhance drug delivery efficiency.

Progress in enzyme-powered micro/nanomotors in diagnostics and therapeutics

Enzyme-powered micro/nanomotors (EMNMs) represent cutting-edge research taking advantage of enzymes as biocatalysts to provide a driving force for micro/nanomotors. Up to now, EMNMs have been designed to be powered by catalase, urease, lipase, collagenase, compound enzymes, etc. They not only have good biocompatibility and biosafety but also possess the unique ability to utilize physiologically relevant fuel to achieve autonomous propulsion through in vivo catalytic reactions. This innovation has opened exciting possibilities for medical applications of EMNMs. Given the fact that the human body is naturally abundant with substrates available for enzymatic reactions, EMNMs can effectively exploit the complex microenvironment associated with diseases, enabling the diagnosis and treatment of various medical conditions. In this review, we first introduce different kinds of EMNMs applied in specific environments for the diagnosis and treatment of diseases, while highlighting their advancements for revolutionizing healthcare practices. Then, we address the challenges faced in this rapidly evolving field, and at last, the potential future development directions are discussed. As the potential of EMNMs becomes increasingly evident, continued research and exploration are essential to unlock their full capabilities and to ensure their successful integration into clinical applications.

Bionic nanovesicles sequentially treat flaps with different durations of ischemia by thrombolysis and prevention of ischemia-reperfusion injury

Flap transplantation is a critical part of the recovery process for patients who have undergone tumor resection. However, the process of ischemia-reperfusion injury during flap transplantation and the resulting high-risk thrombotic microenvironment are unavoidable. In this study, based on an in-depth investigation of the ischemia time and prognosis of transplanted flaps, we propose a treatment strategy using sequential thrombolysis and ischemia-reperfusion injury prevention tailored to the ischemia time. This approach is designed to minimize the likelihood of thrombus formation and to clear the intravascular inflammatory microenvironment, with the aim of preventing and salvaging ischemic flaps. Specifically, we have successfully constructed a clinical-grade bionic vesicle, UK-PBNZ@PM, a system that cleverly incorporates drug components that have been widely used in clinical applications, thereby demonstrating a high degree of clinical translational potential. Prussian blue nano-enzymes (PBNZ) are the core component and demonstrate remarkable efficacy against ischemia-reperfusion injury due to their excellent biocompatibility, robust reactive oxygen species (ROS) scavenging capacity and anti-inflammatory properties. At the same time, urokinase (UK), a key pharmaceutical agent in antithrombotic therapy, has been effectively incorporated into the system, enhancing its ability to prevent and treat thrombosis. In addition, the integration of a platelet membrane (PM) has endowed the bionic vesicles with precise targeting and delivery capabilities, ensuring that the drugs can reach the lesion directly and facilitate efficient and precise release. The experimental results demonstrated that an ischemia-timed strategy can not only efficiently promote thrombolysis, but also effectively remove harmful elements in the microenvironment of ischemia-reperfusion injury. This discovery represents a new and promising approach to the treatment of thrombosis.

Branched silver-iron oxide nanoparticles enabling highly effective targeted and localised drug-free thrombolysis

Ultrasound has been widely used as an external stimulus to trigger drug release from nanomaterials in thrombosis treatment. Here, we introduce a novel strategy leveraging nanomaterials not for drug delivery, but for enhancing US-induced thrombolysis. This innovative strategy is particularly significant, as thrombolytic drugs inherently pose a risk of systemic bleeding. We combined branched silver-iron oxide nanoparticles (AgIONPs) with low-intensity focused ultrasound to evaluate their thrombolytic potential. Binding assays in in vitro human blood clots and in a thrombosis mouse model confirmed that the targeted AgIONPs specifically bound to thrombi. Upon ultrasound activation, AgIONPs facilitated thrombolysis via two key mechanisms: hyperthermia driven by the nanoparticle-mediated thermal conversion, and mechanical shear forces induced by ultrasound. The combination of AgIONPs and US generated a synergistic thrombolytic effect, demonstrating significant efficacy in both in vitro and in vivo.

Thrombin-Responsive and Sequential Targeted Nanoplatform for Synergistic Thrombolysis Therapy

Traditional thrombolytic therapy is limited by low specificity, uncontrollable bleeding complications, and secondary vascular re-embolism. To address this issue, we developed a thrombin-responsive and sequential targeted nanoplatform (MMSN-UK/TI@pep-Fuco) for efficient thrombolysis based on the attack-defense-protection integrated strategy. Herein, the multilevel mesoporous silica nanoparticle with multiple pore sizes was synthesized and modified with fucoidan (Fuco) using the compound peptide (pep) as a bridge to form multifunctional drug carriers MMSN@pep-Fuco. Then, urokinase (UK) and tirofiban (TI) were sequentially loaded into MMSN@pep-Fuco to obtain MMSN-UK/TI@pep-Fuco nano drug delivery systems (NDDS). In vitro and in vivo results demonstrated that MMSN-UK/TI@pep-Fuco maintained stability in the blood circulation to reduce bleeding risk (protection). Once arriving at the thrombus clots, Fuco facilitated NDDS identification and accumulation via P-selectin-mediated active targeting. Thereafter, Fuco coating on the surface of MMSN-UK/TI@pep-Fuco was shed in response to thrombin and then allowed quick release of UK from larger pores to achieve rapid thrombolysis (attack). Next, the exposed LS-MMSN/TI core NPs can continue colonizing at thrombolysis sites, and then TI loaded in smaller pores was released slowly and continuously to prevent re-embolization of blood vessels (defense). Pharmacodynamic results showed that the final thrombus blockage rate of the MMSN-UK/TI@pep-Fuco treatment group was only 4.87% with a relatively low bleeding risk. This nanoplatform provided a new strategy for the treatment of arterial thrombosis and related diseases.

Emerging Targets, Novel Directions, and Innovative Approaches in Thrombosis Therapy

In clinical practice, antiplatelet, anticoagulant and fibrinolytic drugs are the mainstay of thrombosis treatment, but their potential bleeding side effects limit their widespread use. Therefore, modifying these existing drugs or developing new therapies that mitigate bleeding risks while maintaining their efficacy and utilization is necessary. Since the critical role of platelets in thrombosis is closely related to their cell surface receptors, intracellular signaling pathways and metabolism, current research focuses on these three major classes of platelet targets to develop new antithrombotic drugs. The coagulation cascade has always been the main target of anticoagulant drugs, but since the role of molecules of the contact system is more critical in thrombosis than in hemostasis, molecules targeting the contact system, such as FXIa and FXIIa, have become the main direction of anticoagulant drug research at present. Moreover, since the inflammatory response has been found to be significantly associated with thrombosis in recent years, the development of drugs that target inflammatory pathways, such as inflammasome, has also become a hot topic. This article provides a detailed description of these targets or drug formulations that are currently being investigated, including their mode of action and antithrombotic efficiency, and also points out their existing shortcomings. Moreover, antithrombotic nanomedicines can achieve precise release of drugs, which can greatly improve the thrombolytic efficiency and reduce side effects. In conclusion, this review focuses on summarizing the current new targets and new methods of antithrombotic drug research, hoping to provide a little reference for future related research.

Hybrid Biomembrane-Functionalized Nanorobots Penetrate the Vitreous Body of the Eye for the Treatment of Retinal Vein Occlusion

Intravitreal injections of antivascular endothelial growth factor (VEGF) agents are the primary method for treating retinal vein occlusion (RVO). However, the complex structure of eye anatomy presents ocular barriers that impede drug delivery. Additionally, these drugs only manage the complications associated with RVO and fail to address the underlying cause of vessel occlusions. Here, we describe a method that utilizes functionalized magnetically driven nanorobots to overcome ocular barriers and treat RVO. These nanorobots are developed using a hybrid biomembrane that combines stem cell membranes with liposome-derived membranes, enveloping perfluorohexane, iron oxide nanoparticles, and l-arginine. After intravitreal injection, the nanorobots can move directionally through and penetrate the vitreous body to reach the retina, driven by an external magnetic field. Subsequently, the nanorobots actively target the inflammation sites at occluded vessels due to the presence of stem cell membranes. In a rat model of RVO, enhanced targeting and accumulation in ischemic retinal vessels were demonstrated following intravitreal injections. Furthermore, the application of ultrasound triggers the release of l-arginine at the site of occlusion, stimulating the production of nitric oxide, which promotes vasodilation and restores blood flow, thereby achieving excellent therapeutic efficacy for RVO. We believe these methods hold significant promise for overcoming challenges in ocular drug delivery and effectively treating RVO in clinical applications.

Nanozyme-Shelled Microcapsules for Targeting Biofilm Infections in Confined Spaces

Bacterial infections in irregular and branched confinements pose significant therapeutic challenges. Despite their high antimicrobial efficacy, enzyme-mimicking nanoparticles (nanozymes) face difficulties in achieving localized catalysis at distant infection sites within confined spaces. Incorporating nanozymes into microrobots enables the delivery of catalytic agents to hard-to-reach areas, but poor nanoparticle dispersibility and distribution during fabrication hinder their catalytic performance. To address these challenges, a nanozyme-shelled microrobotic platform is introduced using magnetic microcapsules with collective and adaptive mobility for automated navigation and localized catalysis within complex confinements. Using double emulsions produced from microfluidics as templates, iron oxide and silica nanoparticles are assembled into 100-µm microcapsules, which self-organize into multi-unit, millimeter-size assemblies under rotating magnetic fields. These microcapsules exhibit high peroxidase-like activity, efficiently catalyzing hydrogen peroxide to generate reactive oxygen species (ROS). Notably, microcapsule assemblies display remarkable collective navigation within arched and branched confinements, reaching the targeted apical regions of the tooth canal with high accuracy. Furthermore, these nanozyme-shelled microrobots perform rapid catalysis in situ and effectively kill biofilms on contact via ROS generation, enabling localized antibiofilm action. This study demonstrates a facile method of integrating nanozymes onto a versatile microrobotic platform to address current needs for targeted therapeutic catalysis in complex and confined microenvironments.

Cilia-Mimic Locomotion of Magnetic Colloidal Collectives Enhanced by Low-Intensity Ultrasound for Thrombolytic Drug Penetration

Rapid thrombolysis is very important to reduce complications caused by vascular blockage. A promising approach for improving thrombolysis efficiency is utilizing the permanent magnetically actuated locomotion of nanorobots. However, the thrombolytic drug transportation efficiency is challenged by in-plane rotating locomotion and the insufficient drug penetration limits further improvement of thrombolysis. Inspired by ciliary movement for cargo transportation in human body, in this study, cilia-mimic locomotion of magnetic colloidal collectives is realized under torque-force vortex magnetic field (TFV-MF) by a designed rotating permanent magnet assembly. This cilia-mimic locomotion mode can generate more disturbances to the fluids to improve thrombolytic drug transportation and the increased height and area of colloidal collectives boosted the imaging capability. In addition, low-intensity ultrasound is applied to enhance colloids infiltration by producing the fiber breakage and inducing erythrocyte deformation. In vitro thrombolytic experiments demonstrate that the thrombolysis efficiency increased by 16.2 times compared with that of pure tissue plasminogen activator (tPA) treatments. Furthermore, in vivo rat models of femoral vein thrombosis confirmed that this approach can achieve blood flow recanalization more quickly. The proposed cilia-mimic locomotion of magnetic colloidal collectives combined with low-intensity ultrasound irradiation mode provides a new insight of therapeutic interventions for vascular thrombus by enhancing drug penetration.

Emerging advances in drug delivery systems (DDSs) for optimizing cancer complications

The management and treatment of tumor complications pose continuous challenges due to the inherent complexity. However, the advent of drug delivery systems (DDSs) brings promising opportunities to address the tumor complications using innovative technological approaches. This review focuses on common oncological complications, including cancer thrombosis, malignant serous effusion, tumor-associated infections, cancer pain, and treatment-related complications. Emphasis was placed on the application and potential of DDSs in mitigating and treating these tumor complications, and we delved into the underlying mechanisms of common cancer-associated complications, discussed the limitations of conventional treatments, and outlined the current status and potential development of DDSs for various complications in this review. Moreover, we have discussed the existing challenges in DDSs research, underscoring the need for addressing issues related to biocompatibility and targeting of DDSs, optimizing drug delivery routes, and enhancing delivery efficiency and precision. In conclusion, DDSs offer promising avenues for treating cancer complications, offering the potential for the development of more effective and safer drug delivery strategies, thereby improving the quality of life and survival rates of cancer patients.

New magnetic iron nanoparticle doped with selenium nanoparticles and the mechanisms of their cytoprotective effect on cortical cells under ischemia-like conditions

Ischemic stroke is the cause of high mortality and disability Worldwide. The material costs of stroke treatment and recovery are constantly increasing, making the search for effective and more cost-effective treatment approaches an urgent task for modern biomedicine. In this study, iron nanoparticles doped with selenium nanoparticles, FeNP@SeNPs, which are three-layered structures, were created and characterized using physical methods. Fluorescence microscopy, inhibitor and PCR analyzes were used to determine the signaling pathways involved in the activation of the Ca2+ signaling system of cortical astrocytes and the protection of cells from ischemia-like conditions (oxygen-glucose deprivation and reoxygenation). In particular, when using magnetic selenium nanoparticles together with electromagnetic stimulation, an additional pathway for nanoparticle penetration into the cell is activated through the activation of TRPV4 channels and the mechanism of their endocytosis is facilitated. It has been shown that the use of magnetic selenium nanoparticles together with magnetic stimulation represents an advantage over the use of classical selenium nanoparticles, as the effective concentration of nanoparticles can be reduced many times over.

Sonothrombolysis Using Microfluidically Produced Microbubbles in a Murine Model of Deep Vein Thrombosis

The need for safe and effective methods to manage deep vein thrombosis (DVT), given the risks associated with anticoagulants and thrombolytic agents, motivated research into innovative approaches to resolve blood clots. In response to this challenge, sonothrombolysis is being explored as a technique that combines microbubbles, ultrasound, and thrombolytic agents to facilitate the aggressive dissolution of thrombi. Prior studies have indicated that relatively large microbubbles accelerate the dissolution process, either in an in vitro or an arterial model. However, sonothrombolysis using large microbubbles must be evaluated in venous thromboembolism diseases, where blood flow velocity is not comparable. In this study, the efficacy of sonothrombolysis was validated in a murine model of pre-existing DVT. During therapy, microfluidically produced microbubbles of 18 μm diameter and recombinant tissue plasminogen activator (rt-PA) were administered through a tail vein catheter for 30 min, while ultrasound was applied to the abdominal region of the mice. Three-dimensional ultrasound scans were performed before and after therapy for quantification. The residual volume of the thrombi was 20% in animals post sonothrombolysis versus 52% without therapy ( p = 0.012 < 0.05 ), indicating a significant reduction in DVT volume. Histological analysis of tissue sections confirmed a reduction in DVT volume post-therapy. Therefore, large microbubbles generated from a microfluidic device show promise in ultrasound-assisted therapy to address concerns related to venous thromboembolism.

Swarm Autonomy: From Agent Functionalization to Machine Intelligence

Swarm behaviors are common in nature, where individual organisms collaborate via perception, communication, and adaptation. Emulating these dynamics, large groups of active agents can self-organize through localized interactions, giving rise to complex swarm behaviors, which exhibit potential for applications across various domains. This review presents a comprehensive summary and perspective of synthetic swarms, to bridge the gap between the microscale individual agents and potential applications of synthetic swarms. It is begun by examining active agents, the fundamental units of synthetic swarms, to understand the origins of their motility and functionality in the presence of external stimuli. Then inter-agent communications and agent-environment communications that contribute to the swarm generation are summarized. Furthermore, the swarm behaviors reported to date and the emergence of machine intelligence within these behaviors are reviewed. Eventually, the applications enabled by distinct synthetic swarms are summarized. By discussing the emergent machine intelligence in swarm behaviors, insights are offered into the design and deployment of autonomous synthetic swarms for real-world applications.

On-Site Self-Penetrating Nanomedicine Enabling Dual-Priming Drug Activation and Inside-Out Thrombus Ablation

Main conventional antithrombotic therapies often suffer from unsatisfactory treatment outcomes and the risk of undesirable tissue hemorrhage. Deep clot penetration, on-demand drug activation, and release within the clots remain significant challenges. While past efforts to develop nanomedicines and prodrugs have improved safety at the expense of therapeutic effects. Herein, we develop a self-piercing and self-activating nanoassembly composed of an oxidation-sensitive prodrug (TGL-S-Fmoc, TSF) of ticagrelor (TGL) and IR808 (a photothermal/photodynamic dual-effect photosensitizer). TSF readily coassembles with IR808 into a carrier-free hybrid nanomedicine. Upon laser irradiation, IR808 enables photothermal thrombolysis and deep clot penetration of TSF while also synergistically facilitating prodrug activation triggered by IR808-generated singlet oxygen (1O2) and the endogenous hydrogen peroxide within the clots. Following fibrin-targeting modification, the nanoassembly achieves self-indicating thrombus-targeted accumulation, self-piercing deep clot penetration, dual-priming prodrug activation, and inside-out thrombus ablation with favorable safety in vivo. This study advances the clinical translation of antithrombotic prodrugs and nanomedicines.

Low‐Intensity Focused Ultrasound‐Responsive Nanobubbles Enhance Thrombus Targeting and Penetration for Highly Effective Thrombolytic Therapy

Owing to the short half‐life, restricted targeting capability, and high bleeding risk associated with thrombolytic drugs, safe and effective thrombolytic therapy remains challenging. Based on the natural targeting and immune escape functions of platelets during thrombosis, spatiotemporally controlled nanobubbles (PAF@M) are developed to specifically target thrombus sites. These nanobubbles are designed by loading an air core of perfluoropentane (PFP) and l‐arginine within a poly(lactic‐co‐glycolic acid) shell and coating it with a platelet membrane. Under stimulation with low‐intensity focused ultrasound (LIFU), physical shear stress promotes deep penetration of the nanobubbles into the thrombus. Moreover, the liquid–gas phase transition of PFP and the release of nitric oxide synergistically enhance ultrasonic cavitation to disrupt the thrombus structure. In terms of mechanism, these gas molecules induce acoustic pore action to disrupt the fibrin network structure, loosening the interior of the thrombus, and act specifically on the surfaces of red blood cells and activated platelets, launching a comprehensive attack on the thrombus. It is believed that PAF@M nanobubbles will delay the progression of thrombosis and achieve safe and highly effective thrombolytic therapy. This simple LIFU response principle has the potential to be a safer and more effective alternative to current pharmaceutical approaches.

Intravenous administration of blood-brain barrier-crossing conjugates facilitate biomacromolecule transport into central nervous system

Delivery of biomacromolecules to the central nervous system (CNS) remains challenging because of the restrictive nature of the blood-brain barrier (BBB). We developed a BBB-crossing conjugate (BCC) system that facilitates delivery into the CNS through γ-secretase-mediated transcytosis. Intravenous administration of a BCC10-oligonucleotide conjugate demonstrated effective transportation of the oligonucleotide across the BBB and gene silencing in wild-type mice, human brain tissues and an amyotrophic lateral sclerosis mouse model.

Bubble-Inspired Multifunctional Magnetic Microrobots for Integrated Multidimensional Targeted Biosensing

Microrobots possessing multifunctional integration are desired for therapeutics and biomedicine applications. However, existing microrobots with desired functionalities need to be fabricated through complex procedures due to their constrained volume, limited manufacturing processes, and lack of effective in vivo observation methods. Inspired by bubbles exhibiting various abilities, we report magnetic air bubble microrobots with simpler structures to simultaneously integrate multiple functions, including microcargo delivery, multimode locomotion, imaging, and biosensing. Contributed by buoyancy and magnetic actuation to overcome obstacles, flexible three-dimensional locomotion is implemented, guaranteeing the integrity of micro-objects adsorbed on the surface of the air bubble microrobot. Introducing air microbubbles enhances the ultrasound imaging capability of microrobots in the vascular system of mice in vivo, facilitating ample medical applications. Moreover, air-liquid reactions endow microrobots with rapid pH biosensing. This work provides a unique strategy to utilize relatively simple air bubbles to achieve the complex functions of microrobots for biomedical applications.

Dual Frequency-Regulated Magnetic Vortex Nanorobots Empower Nattokinase for Focalized Microvascular Thrombolysis

Magnetic nanorobots are emerging players in thrombolytic therapy due to their noninvasive remote actuation and drug loading capabilities. Although the nanorobots with a size under 100 nm are ideal to apply in microvascular systems, the propulsion performance of nanorobots is inevitably compromised due to the limited response to magnetic fields. Here, we demonstrate a nattokinase-loaded magnetic vortex nanorobot (NK-MNR) with an average size around 70 nm and high saturation magnetization for mechanical propelling and thermal responsive thrombolysis under a magnetic field with dual frequencies. The nanorobots are stable in suspension and undergo the magneto-steered assembly into chain-like NK-MNRs, which are regulated to generate magnetic forces to mechanically damage and penetrate the thrombus by the low-frequency rotating magnetic field. Synergistically, enhanced magnetic hyperthermia is triggered by an alternating magnetic field of high frequency, enabling heat-induced NK release and fibrinolysis. In this dual frequency-regulated magnetothrombolysis (fRMT) strategy, nanorobots collaborate under the dual magnetic energy conversion model to achieve the vasculature recanalization rate of 81.0% in thrombotic mice. Overall, the nanorobot with the special magnetic vortex property and multimodel controls is a promising nanoplatform for in vivo focalized microvascular thrombolysis.

Achieving Immune Activation by Suppressing the IDO1 Checkpoint with Sono-Targeted Biobromination for Antitumor Combination Immunotherapy

Indoleamine-2,3-dioxygenase-1 (IDO1) pathogenically suppresses immune cell infiltration and promotes tumor cell immune escape by overmetabolizing tryptophan to N-formyl kynurenine in the tumor microenvironment (TME). However, it remains challenging for IDO1 immune checkpoint inhibitors to achieve a significant potency of progression-free survival. Here, we developed a breakthrough in IDO1 inhibition by sono-targeted biobromination reaction using immunostimulating hypobromic-P-phenylperoxydibenzoic acid-linked metallic organic framework nanomedicine (H-MOF NM) to remodel the TME from debrominated hypoxia into hypobromated normoxia and activate the IDO1 immune pathway with in vitro and in vivo remarkable antitumor efficacy. H-MOF NM contains Br+ and O- active ingredients with an enlarged band gap to deactivate IDO1 through an innovative biochemical mechanism, taking control over brominating IDO1 amino acid residues at the active sites in the remodeled TME and subsequently activating the immune response, including DC maturation, T-cell activation, and macrophage polarization. Importantly, the H-MOF NM achieves multiple immune responses with high tumor regression potency by combination sono-immunotherapy. This study describes an excellent IDO1 inhibition strategy through the development of immune biobrominative H-MOF nanomedicine and highlights efficient combination immunotherapy for tumor treatment.

Phototactic/Photosynthetic/Magnetic-Powered Chlamydomonas Reinhardtii-Metal-Organic Frameworks Micro/Nanomotors for Intelligent Thrombolytic Management and Ischemia Alleviation

Thrombosis presents a critical health threat globally, with high mortality and incidence rates. Clinical treatment faces challenges such as low thrombolytic agent bioavailability, thrombosis recurrence, ischemic hypoxia damage, and neural degeneration. This study developed biocompatible Chlamydomonas Reinhardtii micromotors (CHL) with photo/magnetic capabilities to address these needs. These CHL micromotors, equipped with phototaxis and photosynthesis abilities, offer promising solutions. A core aspect of this innovation involves incorporating polysaccharides (glycol chitosan (GCS) and fucoidan (F)) into ferric Metal-organic frameworks (MOFs), loaded with urokinase (UK), and subsequently self-assembled onto the multimodal CHL, forming a core-shell microstructure (CHL@GCS/F-UK-MOF). Under light-navigation, CHL@GCS/F-UK-MOF is shown to penetrate thrombi, enhancing thrombolytic biodistribution. Combining CHL@GCS/F-UK-MOF with the magnetic hyperthermia technique achieves stimuli-responsive multiple-release, accelerating thrombolysis and rapidly restoring blocked blood vessels. Moreover, this approach attenuates thrombi-induced ischemic hypoxia disorder and tissue damage. The photosynthetic and magnetotherapeutic properties of CHL@GCS/F-UK-MOF, along with their protective effects, including reduced apoptosis, enhanced behavioral function, induced Heat Shock Protein (HSP), polarized M2 macrophages, and mitigated hypoxia, are confirmed through biochemical, microscopic, and behavioral assessments. This multifunctional biomimetic platform, integrating photo-magnetic techniques, offers a comprehensive approach to cardiovascular management, advancing related technologies.

Beyond silence: evolving ultrasound strategies in the battle against cardiovascular thrombotic challenges

Cardiovascular thrombotic events have long been a perplexing factor in clinical settings, influencing patient prognoses significantly. Ultrasound-mediated acoustic therapy, an innovative thrombolytic treatment method known for its high efficiency, non-invasiveness, safety, and convenience, has demonstrated promising potential for clinical applications and has gradually become a focal point in cardiovascular thrombotic disease research. The current challenge lies in the technical complexities of preparing ultrasound-responsive carriers with thrombus-targeting capabilities and high thrombolytic efficiency. Additionally, optimizing the corresponding acoustic treatment mode is crucial to markedly enhance the thrombolytic effectiveness of ultrasound-mediated acoustic therapy. In light of the current status, this article provides a comprehensive review of the research progress in innovative ultrasound-mediated acoustic therapy for cardiovascular thrombotic diseases. It explores the impact of technical methods, therapeutic mechanisms, and influencing factors on the thrombolytic efficiency and clinical potential of ultrasound-mediated acoustic therapy. The review places particular emphasis on identifying solutions and key considerations in addressing the challenges associated with this cutting-edge therapeutic approach.

Ultrasound-Based Micro-/Nanosystems for Biomedical Applications

Due to the intrinsic non-invasive nature, cost-effectiveness, high safety, and real-time capabilities, besides diagnostic imaging, ultrasound as a typical mechanical wave has been extensively developed as a physical tool for versatile biomedical applications. Especially, the prosperity of nanotechnology and nanomedicine invigorates the landscape of ultrasound-based medicine. The unprecedented surge in research enthusiasm and dedicated efforts have led to a mass of multifunctional micro-/nanosystems being applied in ultrasound biomedicine, facilitating precise diagnosis, effective treatment, and personalized theranostics. The effective deployment of versatile ultrasound-based micro-/nanosystems in biomedical applications is rooted in a profound understanding of the relationship among composition, structure, property, bioactivity, application, and performance. In this comprehensive review, we elaborate on the general principles regarding the design, synthesis, functionalization, and optimization of ultrasound-based micro-/nanosystems for abundant biomedical applications. In particular, recent advancements in ultrasound-based micro-/nanosystems for diagnostic imaging are meticulously summarized. Furthermore, we systematically elucidate state-of-the-art studies concerning recent progress in ultrasound-based micro-/nanosystems for therapeutic applications targeting various pathological abnormalities including cancer, bacterial infection, brain diseases, cardiovascular diseases, and metabolic diseases. Finally, we conclude and provide an outlook on this research field with an in-depth discussion of the challenges faced and future developments for further extensive clinical translation and application.

REVIEW: "ISCHEMIC STROKE: From Fibrinolysis to Functional Recovery" Nanomedicine: emerging approaches to treat ischemic stroke

Stroke is responsible for 11% of all deaths worldwide, the majority of which are caused by ischemic strokes, thus making the need to urgently find safe and effective therapies. Today, these can be cured either by mechanical thrombectomy when the thrombus is accessible, or by intravenous injection of fibrinolytics. However, the latter present several limitations, such as potential severe side effects, few eligible patients and low rate of partial and full recovery. To design safer and more effective treatments, nanomedicine appeared in this medical field a few decades ago. This review will explain why nanoparticle-based therapies and imaging techniques are relevant for ischemic stroke management. Then, it will present the different nanoparticle types that have been recently developed to treat this pathology. It will also study the various targeting strategies used to bring nanoparticles to the stroke site, thereby limiting side effects and improving the therapeutic efficacy. Finally, this review will present the few clinical studies testing nanomedicine on stroke and discuss potential causes for their scarcity.

Interventional Removal of Travelling Microthrombi Using Targeted Magnetic Microbubble

Microthrombus is one of the major causes of the sequelae of Corona Virus Disease 2019 (COVID-19 and leads to subsequent embolism and necrosis. Due to their small size and irregular movements, the early detection and efficient removal of microthrombi in vivo remain a great challenge. In this work, an interventional method is developed to identify and remove the traveling microthrombi using targeted-magnetic-microbubbles (TMMBs) and an interventional magnetic catheter. The thrombus-targeted drugs are coated on the TMMBs and magnetic nanoparticles are shelled inside, which allow not only targeted adhesion onto the traveling microthrombi, but also the effective capture by the magnetic catheter in the vessel. In the proof-of-concept experiments in the rat models, the concentration of microthrombus is reduced by more than 60% in 3 min, without damaging the organs. It is a promising method for treating microthrombus issues.

Dual-mode nanoprobe strategy integrating ultrasound and near-infrared light for targeted and synergistic arterial thrombolysis

Efficient thrombolysis in time is crucial for prognostic improvement of patients with acute arterial thromboembolic disease, while limitations and complications still exist in conventional thrombolytic treatment methods. Herein, our study sought to investigate a novel dual-mode strategy that integrated ultrasound (US) and near-infrared light (NIR) with establishment of hollow mesoporous silica nanoprobe (HMSN) which contains Arginine-glycine-aspartate (RGD) peptide (thrombus targeting), perfluoropentane (PFP) (thrombolysis with phase-change and stable cavitation) and indocyanine green (ICG) (thrombolysis with photothermal conversion). HMSN is used as the carrier, the surface is coupled with targeted RGD to achieve high targeting and permeability of thrombus, PFP and ICG are loaded to achieve the collaborative diagnosis and treatment of thrombus by US and NIR, so as to provide a new strategy for the integration of diagnosis and treatment of arterial thrombus. From the in vitro and in vivo evaluation, RGD/ICG/PFP@HMSN can aggregate and penetrate at the site of thrombus, and finally establish the dual-mode directional development and thrombolytic treatment under the synergistic effect of US and NIR, providing strong technical support for the accurate diagnosis and treatment of arterial thrombosis.

An intelligent DNA nanodevice for precision thrombolysis

Thrombosis is a leading global cause of death, in part due to the low efficacy of thrombolytic therapy. Here, we describe a method for precise delivery and accurate dosing of tissue plasminogen activator (tPA) using an intelligent DNA nanodevice. We use DNA origami to integrate DNA nanosheets with predesigned tPA binding sites and thrombin-responsive DNA fasteners. The fastener is an interlocking DNA triplex structure that acts as a thrombin recognizer, threshold controller and opening switch. When loaded with tPA and intravenously administrated in vivo, these DNA nanodevices rapidly target the site of thrombosis, track the circulating microemboli and expose the active tPA only when the concentration of thrombin exceeds a threshold. We demonstrate their improved therapeutic efficacy in ischaemic stroke and pulmonary embolism models, supporting the potential of these nanodevices to provide accurate tPA dosing for the treatment of different thromboses.

pH-Responsive Theranostic Colloidosome Drug Carriers Enable Real-Time Imaging of Targeted Thrombolytic Process with Near-Infrared-II for Deep Venous Thrombosis

Thrombosis can cause life-threatening disorders. Unfortunately, current therapeutic methods for thrombosis using injecting thrombolytic medicines systemically resulted in unexpected bleeding complications. Moreover, the absence of practical imaging tools for thrombi raised dangers of undertreatment and overtreatment. This study develops a theranostic drug carrier, Pkr(IR-Ca/Pda-uPA)-cRGD, that enables real-time monitoring of the targeted thrombolytic process of deep vein thrombosis (DVT). Pkr(IR-Ca/Pda-uPA)-cRGD, which is prepared from a Pickering-emulsion-like system, encapsulates both near-infrared-II (NIR-II) contrast agent (IR-1048 dye, loading capacity: 28%) and urokinase plasminogen activators (uPAs, encapsulation efficiency: 89%), pioneering the loading of multiple drugs with contrasting hydrophilicity into one single-drug carrier. Upon intravenous injection, Pkr(IR-Ca/Pda-uPA)-cRGD considerably targets to thrombi selectively (targeting rate: 91%) and disintegrates in response to acidic thrombi to release IR-1048 dye and uPA for imaging and thrombolysis, respectively. Investigations indicate that Pkr(IR-Ca/Pda-uPA)-cRGD enabled real-time visualization of targeted thrombolysis using NIR-II imaging in DVT models, in which thrombi were eliminated (120 min after drug injection) without bleeding complications. This may be the first study using convenient NIR-II imaging for real-time visualization of targeted thrombolysis. It represents the precision medicine that enables rapid response to acquire instantaneous medical images and make necessary real-time adjustments to diagnostic and therapeutic protocols during treatment.

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.

A photo-responsive self-healing hydrogel loaded with immunoadjuvants and MoS2 nanosheets for combating post-resection breast cancer recurrence

Tumor recurrence after surgical resection remains a significant challenge in breast cancer treatment. Immune checkpoint blockade therapy, as a promising alternative therapy, faces limitations in combating tumor recurrence due to the low immune response rate. In this study, we developed an implantable photo-responsive self-healing hydrogel loaded with MoS2 nanosheets and the immunoadjuvant R837 (PVA-MoS2-R837, PMR hydrogel) for in situ generation of tumor-associated antigens at the post-surgical site of the primary tumor, enabling sustained and effective activation of the immune response. This PMR hydrogel exhibited potential for near-infrared (NIR) light response, tissue adhesion, self-healing, and sustained adjuvant release. When implanted at the site after tumor resection, NIR irradiation triggered a photothermal effect, resulting in the ablation of residual cancer cells. The in situ-generated tumor-associated antigens promoted dendritic cell (DC) maturation. In a mouse model, PMR hydrogel-mediated photothermal therapy combined with immune checkpoint blockade effectively inhibited the recurrence of resected tumors, providing new insights for combating post-resection breast cancer recurrence.

Ultrasound Trigger Ce-Based MOF Nanoenzyme For Efficient Thrombolytic Therapy

The inflammatory damage caused by thrombus formation and dissolution can increase the risk of thrombotic complications on top of cell death and organ dysfunction caused by thrombus itself. Therefore, a rapid and precise thrombolytic therapy strategy is in urgent need to effectively dissolve thrombus and resist oxidation simultaneously. In this study, Ce-UiO-66, a cerium-based metal-organic framework (Ce-MOF) with reactive oxygen species (ROS) scavenging properties, encapsulated by low-immunogenic mesenchymal stem cell membrane with inflammation-targeting properties, is used to construct a targeted nanomedicine Ce-UiO-CM. Ce-UiO-CM is applied in combination with external ultrasound stimulation for thrombolytic therapy in rat femoral artery. Ce-UiO-66 has abundant Ce (III)/Ce (IV) coupling sites that react with hydrogen peroxide (H2O2) to produce oxygen, exhibiting catalase (CAT) activity. The multi-cavity structure of Ce-UiO-66 can generate electron holes, and its pore channels can act as micro-reactors to further enhance its ROS scavenging capacity. Additionally, the porous structure of Ce-UiO-66 and the oxygen produced by its reaction with H2O2 may enhance the cavitation effects of ultrasound, thereby improving thrombolysis efficacy.

Ultrasound imaging guided targeted sonodynamic therapy enhanced by magnetophoretically controlled magnetic microbubbles

Sonodynamic therapy (SDT) utilizes ultrasonic excitation of a sensitizer to generate reactive oxygen species (ROS) to destroy tumor. Two dimensional (2D) black phosphorus (BP) is an emerging sonosensitizer that can promote ROS production to be used in SDT but it alone lacks active targeting effect and showed low therapy efficiency. In this study, a stable dispersion of integrated micro-nanoplatform consisting of BP nanosheets loaded and Fe3O4 nanoparticles (NPs) connected microbubbles was introduced for ultrasound imaging guided and magnetic field directed precision SDT of breast cancer. The targeted ultrasound imaging at 18 MHz and efficient SDT effects at 1 MHz were demonstrated both in-vitro and in-vivo on the breast cancer. The magnetic microbubbles targeted deliver BP nanosheets to the tumor site under magnetic navigation and increased the uptake of BP nanosheets by inducing cavitation effect for increased cell membrane permeability via ultrasound targeted microbubble destruction (UTMD). The mechanism of SDT by magnetic black phosphorus microbubbles was proposed to be originated from the ROS triggered mitochondria mediated apoptosis by up-regulating the pro-apoptotic proteins while down-regulating the anti-apoptotic proteins. In conclusion, the ultrasound theranostic was realized via the magnetic black phosphorus microbubbles, which could realize targeting and catalytic sonodynamic therapy.

Tea polyphenol-derived nanomedicine for targeted photothermal thrombolysis and inflammation suppression

Thrombotic diseases impose a significant global health burden, and conventional drug-based thrombolytic therapies are encumbered by the risk of bleeding complications. In this study, we introduce a novel drug-free nanomedicine founded on tea polyphenols nanoparticles (TPNs), which exhibits multifaceted capabilities for localized photothermal thrombolysis. TPNs were synthesized through a one-pot process under mild conditions, deriving from the monomeric epigallocatechin-3-gallate (EGCG). Within this process, indocyanine green (ICG) was effectively encapsulated, exploiting multiple intermolecular interactions between EGCG and ICG. While both TPNs and ICG inherently possessed photothermal potential, their synergy significantly enhanced photothermal conversion and stability. Furthermore, the nanomedicine was functionalized with cRGD for targeted delivery to activated platelets within thrombus sites, eliciting robust thrombolysis upon laser irradiation across diverse thrombus types. Importantly, the nanomedicine's potent free radical scavenging abilities concurrently mitigated vascular inflammation, thus diminishing the risk of disease recurrence. In summary, this highly biocompatible multifunctional nanomaterial holds promise as a comprehensive approach that combines thrombolysis with anti-inflammatory actions, offering precision in thrombosis treatment.

Dual-Functional Laser-Guided Magnetic Nanorobot Collectives against Gravity for On-Demand Thermo-Chemotherapy of Peritoneal Metastasis

Combining hyperthermic intraperitoneal chemotherapy with cytoreductive surgery is the main treatment modality for peritoneal metastatic (PM) carcinoma despite the off-target effects of chemotherapy drugs and the ineluctable side effects of total abdominal heating. Herein, a laser-integrated magnetic actuation system that actively delivers doxorubicin (DOX)-grafted magnetic nanorobot collectives to the tumor site in model mice for local hyperthermia and chemotherapy is reported. With intraluminal movements controlled by a torque-force hybrid magnetic field, these magnetic nanorobots gather at a fixed point coinciding with the position of the localization laser, moving upward against gravity over a long distance and targeting tumor sites under ultrasound imaging guidance. Because aggregation enhances the photothermal effect, controlled local DOX release is achieved under near-infrared laser irradiation. The targeted on-demand photothermal therapy of multiple PM carcinomas while minimizing off-target tissue damage is demonstrated. Additionally, a localization/treatment dual-functional laser-integrated magnetic actuation system is developed and validated in vivo, offering a potentially clinically feasible drug delivery strategy for targeting PM and other intraluminal tumors.

Dual-Frequency Ultrasound Assisted Thrombolysis in Interventional Therapy of Deep Vein Thrombosis

Deep vein thrombosis (DVT) is one of the main causes of disability and death worldwide. Currently, the treatment of DVT still needs a long time and faces a high risk of major bleeding. It is necessary to find a rapid and safe method for the therapy of DVT. Here, a dual-frequency ultrasound assisted thrombolysis (DF-UAT) is reported for the interventional treatment of DVT. A series of piezoelectric elements are placed in an interventional catheter to emit ultrasound waves with two independent frequencies in turn. The low-frequency ultrasound drives the drug-loaded droplets into the thrombus, while the high-frequency ultrasound causes the cavitation of the droplets in the thrombus. With the joint effect of the enhanced drug diffusion and the cavitation under the dual-frequency ultrasound, the thrombolytic efficacy can be improved. In a proof-of-concept experiment performed with living sheep, the recanalization of the iliac vein is realized in 15 min using the DF-UAT technology. Therefore, the DF-UAT can be one of the most promising methods in the interventional treatment of DVT.

Ultrasound-Stimulated "Exocytosis" by Cell-Like Microbubbles Enhances Antibacterial Species Penetration and Immune Activation Against Implant Infection

Host immune systems serving as crucial defense lines are vital resisting mechanisms against biofilm-associated implant infections. Nevertheless, biofilms hinder the penetration of anti-bacterial species, inhibit phagocytosis of immune cells, and frustrate host inflammatory responses, ultimately resulting in the weakness of the host immune system for biofilm elimination. Herein, a cell-like construct is developed through encapsulation of erythrocyte membrane fragments on the surface of Fe3 O4 nanoparticle-fabricated microbubbles and then loaded with hydroxyurea (EMB-Hu). Under ultrasound (US) stimulation, EMB-Hu undergoes a stable oscillation manner to act in an "exocytosis" mechanism for disrupting biofilm, releasing agents, and enhancing penetration of catalytically generated anti-bacterial species within biofilms. Additionally, the US-stimulated "exocytosis" by EMB-Hu can activate pro-inflammatory macrophage polarization and enhance macrophage phagocytosis for clearance of disrupted biofilms. Collectively, this work has exhibited cell-like microbubbles with US-stimulated "exocytosis" mechanisms to overcome the biofilm barrier and signal macrophages for inflammatory activation, finally achieving favorable therapeutic effects against implant infections caused by methicillin-resistant Staphylococcus aureus (MRSA) biofilms.

Microbubble Biointerfacing by Regulation of the Platelet Membrane Surfactant Activity at the Gas-Liquid Interface for Acute Thrombosis Targeting

Biointerfacing nanomaterials with cell membranes has been successful in the functionalization of nanoparticles or nanovesicles, but microbubble functionalization remains challenging due to the unique conformation of the lipid monolayer structure at the gas-liquid interface that provides insufficient surfactant activity. Here, we describe a strategy to rationally regulate the surfactant activity of platelet membrane vesicles by adjusting the ratio of proteins to lipids through fusion with synthetic phospholipids (i.e., liposomes). A "platesome" with the optimized protein-to-lipid ratio can be assembled at the gas-liquid interface in the same manner as pulmonary surfactants to stabilize a microsized gas bubble. Platesome microbubbles (PMBs) inherited 61.4 % of the platelet membrane vesicle proteins and maintained the active conformation of integrin αIIbβ3 without the talin 1 for fibrin binding. We demonstrated that the PMBs had good stability, long circulation, and superior functionality both in vitro and in vivo. Moreover, by molecular ultrasound imaging, the PMBs provide up to 11.8 dB of ultrasound signal-to-noise ratio enhancement for discriminating between acute and chronic thrombi. This surface tension regulating strategy may provide a paradigm for biointerfacing microbubbles with cell membranes, offering a potential new approach for the construction of molecular ultrasound contrast agents for the diagnosis of different diseases.

Light-controlled soft bio-microrobot

Micro/nanorobots hold exciting prospects for biomedical and even clinical applications due to their small size and high controllability. However, it is still a big challenge to maneuver micro/nanorobots into narrow spaces with high deformability and adaptability to perform complicated biomedical tasks. Here, we report a light-controlled soft bio-microrobots (called "Ebot") based on Euglena gracilis that are capable of performing multiple tasks in narrow microenvironments including intestinal mucosa with high controllability, deformability and adaptability. The motion of the Ebot can be precisely navigated via light-controlled polygonal flagellum beating. Moreover, the Ebot shows highly controlled deformability with different light illumination duration, which allows it to pass through narrow and curved microchannels with high adaptability. With these features, Ebots are able to execute multiple tasks, such as targeted drug delivery, selective removal of diseased cells in intestinal mucosa, as well as photodynamic therapy. This light-controlled Ebot provides a new bio-microrobotic tool, with many new possibilities for biomedical task execution in narrow and complicated spaces where conventional tools are difficult to access due to the lack of deformability and bio-adaptability.

tPA-anchored nanorobots for in vivo arterial recanalization at submillimeter-scale segments

Micro/nanorobots provide a promising approach for intravascular therapy with high precision. However, blood vessel is a highly complex system, and performing interventional therapy in those submillimeter segments remains challenging. While micro/nanorobots can enter submillimeter segments, they may still comprise nonbiodegradable parts, posing a considerable challenge for post-use removal. Here, we developed a retrievable magnetic colloidal microswarm, composed of tPA-anchored Fe3O4@mSiO2 nanorobots (tPA-nbots), to archive tPA-mediated thrombolysis under balloon catheter-assisted magnetic actuation with x-ray fluoroscopy imaging system (CMAFIS). By deploying tPA-nbot transcatheter to the vicinity of the thrombus, the tPA-nbot microswarms were magnetically actuated to the blood clot at the submillimeter vessels with high precision. After thrombolysis, the tPA-nbots can be retrieved via the CMAFIS, as demonstrated in ex vivo organ of human placenta and in vivo carotid artery of rabbit. The proposed colloidal microswarm provides a promising robotic tool with high spatial precision for enhanced thrombolysis with low side effects.

Targeting Nanomotor with Near-Infrared/Ultrasound Triggered-Transformation for Polystage-Propelled Cascade Thrombolysis and Multimodal Imaging Diagnosis

Nowadays, cardiovascular and cerebrovascular diseases caused by venous thromboembolism become main causes of mortality around the world. The current thrombolytic strategies in clinics are confined primarily due to poor penetration of nanoplatforms, limited thrombolytic efficiency, and extremely-low imaging accuracy. Herein, a novel nanomotor (NM) is engineered by combining iron oxide/perfluorohexane (PFH)/urokinase (UK) into liposome nanovesicle, which exhibits near-infrared/ultrasound (NIR/US) triggered transformation, achieves non-invasive vein thrombolysis, and realizes multimodal imaging diagnosis altogether. Interestingly, a three-step propelled cascade thrombolytic therapy is revealed from such intelligent NM. First, the NM is effectively herded at the thrombus site under guidance of a magnetic field. Afterwards, stimulations of NIR/US propel phase transition of PFH, which intensifies penetration of the NM toward deep thrombus dependent on cavitation effect. Ultimately, UK is released from the collapsed NM and achieves pharmaceutical thrombolysis in a synergistic way. After an intravenous injection of NM in vivo, the whole thrombolytic process is monitored in real-time through multimodal photoacoustic, ultrasonic, and color Doppler ultrasonic imagings. Overall, such advanced nanoplatform provides a brand-new strategy for time-critical vein thrombolytic therapy through efficient thrombolysis and multimodal imaging diagnosis.

Recent advances and clinical translation of liposomal delivery systems in cancer therapy

The limitations of conventional cancer treatment are driving the emergence and development of nanomedicines. Research in liposomal nanomedicine for cancer therapy is rapidly increasing, opening up new horizons for cancer treatment. Liposomal nanomedicine, which focuses on targeted drug delivery to improve the therapeutic effect of cancer while reducing damage to normal tissues and cells, has great potential in the field of cancer therapy. This review aims to clarify the advantages of liposomal delivery systems in cancer therapy. We describe the recent understanding of spatiotemporal fate of liposomes in the organism after different routes of drug administration. Meanwhile, various types of liposome-based drug delivery systems that exert their respective advantages in cancer therapy while reducing side effects were discussed. Moreover, the combination of liposomal agents with other therapies (such as photodynamic therapy and photothermal therapy) has demonstrated enhanced tumor-targeting efficiency and therapeutic efficacy. Finally, the opportunities and challenges faced by the field of liposome nanoformulations for entering the clinical treatment of cancer are highlighted.

Swarming magnetic nanorobots bio-interfaced by heparinoid-polymer brushes for in vivo safe synergistic thrombolysis

Biocompatible swarming magnetic nanorobots that work in blood vessels for safe and efficient targeted thrombolytic therapy in vivo are demonstrated. This is achieved by using magnetic beads elaborately grafted with heparinoid-polymer brushes (HPBs) upon the application of an alternating magnetic field B(t). Because of the dense surface charges bestowed by HPBs, the swarming nanorobots demonstrate reversible agglomeration-free reconfigurations, low hemolysis, anti-bioadhesion, and self-anticoagulation in high-ionic-strength blood environments. They are confirmed in vitro and in vivo to perform synergistic thrombolysis efficiently by "motile-targeting" drug delivery and mechanical destruction. Moreover, upon the completion of thrombolysis and removal of B(t), the nanorobots disassemble into dispersed particles in blood, allowing them to safely participate in circulation and be phagocytized by immune cells without apparent organ damage or inflammatory lesion. This work provides a rational multifaceted HPB biointerfacing design strategy for biomedical nanorobots and a general motile platform to deliver drugs for targeted therapies.

Advances in smart delivery of magnetic field-targeted drugs in cardiovascular diseases

Magnetic Drug Targeting (MDT) is of particular interest to researchers because of its good loading efficiency, targeting accuracy, and versatile use in vivo. Cardiovascular Disease (CVD) is a global chronic disease with a high mortality rate, and the development of more precise and effective treatments is imminent. A growing number of studies have begun to explore the feasibility of MDT in CVD, but an up-to-date systematic summary is still lacking. This review discusses the current research status of MDT from guiding magnetic fields, magnetic nanocarriers, delivery channels, drug release control, and safety assessment. The current application status of MDT in CVD is also critically introduced. On this basis, new insights into the existing problems and future optimization directions of MDT are further highlighted.

rtPA-loaded fucoidan polymer microbubbles for the targeted treatment of stroke

Systemic injection of thrombolytic drugs is the gold standard treatment for non-invasive blood clot resolution. The most serious risks associated with the intravenous injection of tissue plasminogen activator-like proteins are the bleeding complication and the dose related neurotoxicity. Indeed, the drug has to be injected in high concentrations due to its short half-life, the presence of its natural blood inhibitor (PAI-1) and the fast hepatic clearance (0.9 mg/kg in humans, 10 mg/kg in mouse models). Overall, there is a serious need for a dose-reduced targeted treatment to overcome these issues. We present in this article a new acoustic cavitation-based method for polymer MBs synthesis, three times faster than current hydrodynamic-cavitation method. The generated MBs are ultrasound responsive, stable and biocompatible. Their functionalization enabled the efficient and targeted treatment of stroke, without side effects. The stabilizing shell of the MBs is composed of Poly-Isobutyl Cyanoacrylate (PIBCA), copolymerized with fucoidan. Widely studied for its targeting properties, fucoidan exhibit a nanomolar affinity for activated endothelium and activated platelets (P-selectins). Secondly, the thrombolytic agent (rtPA) was loaded onto microbubbles (MBs) with a simple adsorption protocol. Hence, the present study validated the in vivo efficiency of rtPA-loaded Fuco MBs to be over 50 % more efficient than regular free rtPA injection for stroke resolution. In addition, the relative injected rtPA grafted onto targeting MBs was 1/10th of the standard effective dose (1 mg/kg in mouse). As a result, no hemorrhagic event, BBB leakage nor unexpected tissue distribution were observed.

Reversible Microwheel Translation Induced by Polymer Depletion

For in vivo applications, microbots (μbots) must move, which is a need that has led to designs, such as helical swimmers, that translate through the bulk fluid. We have previously demonstrated that, upon application of a rotating magnetic field, colloidal particles in aqueous systems can be reversibly assembled from superparamagnetic particles into μbots that translate along surfaces using wet friction. Here, we show that high-molecular-weight polymers of a size that approaches the length scale of the gap between the μbot and surface can be excluded, impacting μbot transport. Using xanthan gum as a convenient high-molecular-weight model, we determine that polymer depletion imparts only a weak effect on colloid-surface interactions but has a significant influence on local viscosity, which is an effect great enough to induce a reversal in the μbot translation direction.