Biological Mediator-Propelled Nanosweeper for Nonpharmaceutical Thrombus Therapy

Retracted article: The role of second generation sequencing technology and nanomedicine in the monitoring and treatment of lower extremity deep vein thrombosis susceptibility genes

Rong Chang, Chunsheng Wang, Xiangqi Kong, Wenhui Li and Jinchun Wu. The role of second generation sequencing technology and nanomedicine in the monitoring and treatment of lower extremity deep vein thrombosis susceptibility genes. Bioengineered. 2021 Nov. doi: 10.1080/21655979.2021.2003926.Since publication, significant concerns have been raised about the compliance with ethical policies for human research and the integrity of the data reported in the article.When approached for an explanation, the authors provided some original data but were not able to provide all the necessary supporting information. As verifying the validity of published work is core to the scholarly record's integrity, we are retracting the article. All authors listed in this publication have been informed.We have been informed in our decision-making by our editorial policies and the COPE guidelines.The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as 'Retracted.'

Tumor-Specific Nano-Herb Delivery System with High L-Arginine Loading for Synergistic Chemo and Gas Therapy against Cervical Cancer

Cancer metastasis poses significant challenges in current clinical therapy. Osthole (OST) has demonstrated efficacy in treating cervical cancer and inhibiting metastasis. Despite these positive results, its limited solubility, poor oral absorption, low bioavailability, and photosensitivity hinder its clinical application. To address this limitation, a glutathione (GSH)-responded nano-herb delivery system (HA/MOS@OST&L-Arg nanoparticles, HMOA NPs) is devised for the targeted delivery of OST with cascade-activatable nitric oxide (NO) release. The HMOA NPs system is engineered utilizing enhanced permeability and retention (EPR) effects and active targeting mediated by hyaluronic acid (HA) binding to glycoprotein CD44. The cargoes, including OST and L-Arginine (L-Arg), are released rapidly due to the degradation of GSH-responsive mesoporous organic silica (MOS). Then abundant reactive oxygen species (ROS) are produced from OST in the presence of high concentrations of NAD(P)H quinone oxidoreductase 1 (NQO1), resulting in the generation of NO and subsequently highly toxic peroxynitrite (ONOO-) by catalyzing guanidine groups of L-Arg. These ROS, NO, and ONOO- molecules have a direct impact on mitochondrial function by reducing mitochondrial membrane potential and inhibiting adenosine triphosphate (ATP) production, thereby promoting increased apoptosis and inhibiting metastasis. Overall, the results indicated that HMOA NPs has great potential as a promising alternative for the clinical treatment of cervical cancer.

NIR Light-Fuse Drug-Free Photothermal Armor-Piercing Microcapsule for Femoral Vein Thrombosis Therapy

Acute thrombosis and its complications are leading global causes of disability and death. Existing thrombolytic drugs, such as alteplase and urokinase (UK), carry a significant bleeding risk during clinical treatments. Thus, the development of a novel thrombolysis strategy is of utmost urgency. Based on the previous work, the hollow structure of microcapsules (MC) is fabricated. Subsequently, armor-piercing MC, known as Fucoidan/S-Nitrosoglutathione/Melanin@MC (FGM@MC) is obtained, using a layer-by-layer (LBL) self-assembly method. Utilizing near-infrared (NIR) light as a trigger, the FGM@MC demonstrated photothermal thrombolysis at the site of thrombus due to its stable and outstanding photothermal properties. Simultaneously, photothermal stimulation leads to the release of a significant amount of nitric oxide from the FGM@MC, resulting in cavitation effects for mechanical thrombolysis. In vivo experiments confirmed the stable release of nitric oxide under NIR light irradiation. Treatment of femoral vein thrombosis in rats revealed that the thrombolytic effectiveness of FGM@MC+NIR (53.71%) is comparable to that of UK (59.70%). Notably, FGM@MC does not interfere with the coagulation function of rats and exhibits a favorable safety profile. In conclusion, this study demonstrates that the drug-free armor-piercing microcapsule has significant potential in the treatment of thrombosis, offering a safe and effective alternative to traditional thrombolytic therapies.

Fibrinogen binding to activated platelets and its biomimetic thrombus-targeted thrombolytic strategies

Thrombosis is associated with various fatal arteriovenous syndromes including ischemic stroke, myocardial infarction, and pulmonary embolism. However, current clinical thrombolytic treatment strategies still have many problems in targeting and safety to meet the thrombolytic therapy needs. Understanding the molecular mechanism that underlies thrombosis is critical in developing effective thrombolytic strategies. It is well known that platelets play a central role in thrombosis and the binding of fibrinogen to activated platelets is a common pathway in the process of clot formation. Based on this, a concept of biomimetic thrombus-targeted thrombolytic strategy inspired from fibrinogen binding to activated platelets in thrombosis was proposed, which could selectively bind to activated platelets at a thrombus site, thus enabling targeted delivery and local release of thrombolytic agents for effective thrombolysis. In this review, we first summarized the main characteristics of platelets and fibrinogen, and then introduced the classical molecular mechanisms of thrombosis, including platelet adhesion, platelet activation and platelet aggregation through the interactions of activated platelets with fibrinogen. In addition, we highlighted the recent advances in biomimetic thrombus-targeted thrombolytic strategies which inspired from fibrinogen binding to activated platelets in thrombosis. The possible future directions and perspectives in this emerging area are briefly discussed.

Erythrocyte-Membrane-Camouflaged Magnetic Nanocapsules With Photothermal/Magnetothermal Effects for Thrombolysis

Venous/arterial thrombosis poses significant threats to human health. However, drug-enabled thrombolysis treatment often encounters challenges such as short half-life and low bioavailability. To address these issues, the design of erythrocyte-membrane (EM) camouflaged nanocapsules (USIO/UK@EM) incorporating ultra-small iron oxide (USIO) and urokinase (UK) drug, which exhibits remarkable photothermal/magnetothermal effects and drug delivery ability for venous/arterial thrombolysis, is reported. USIO, UK, and EM are coextruded to fabricate USIO/UK@EM with average sizes of 103.7 nm. As USIO/UK@EM possesses wide photoabsorption and good magnetic properties, its solution demonstrates a temperature increase to 41.8-42.9 °C within 5 min when exposed to an 808 nm laser (0.33 mW cm-2) or alternating magnetic field (AMF). Such photothermal/magnetothermal effect along with UK confers impressive thrombolytic rates of 82.4% and 74.2%, higher than that (≈15%) achieved by UK alone. Further, the EM coating extends the circulating half-life (t1/2 = 3.28 h). When USIO/UK@EM is administered to mice and rabbits, tail vein thrombus in mice and femoral artery thrombus in rabbits can be dissolved by the synergetic effect of thermothrombolysis and UK. Therefore, this study not only offers insights into the rational design of multifunctional biomimetic nanocapsules but also showcases a promising thrombolysis strategy utilizing nanomedicine.

Progress of nanomaterials in the treatment of thrombus

Thrombus has long been the major contributor of death and disability because it can cause adverse effects to varying degrees on the body, resulting in vascular blockage, embolism, heart valve deformation, widespread bleeding, etc. However, clinically, conventional thrombolytic drug treatments have hemorrhagic complication risks and easy to miss the best time of treatment window. Thus, it is an urgent need to investigate newly alternative treatment strategies that can reduce adverse effects and improve treatment effectiveness. Drugs based on nanomaterials act as a new biomedical strategy and promising tools, and have already been investigated for both diagnostic and therapeutic purposes in thrombus therapy. Recent studies have some encouraging progress. In the present review, we primarily concern with the latest developments in the areas of nanomedicines targeting thrombosis therapy. We present the thrombus' formation, characteristics, and biomarkers for diagnosis, overview recent emerging nanomedicine strategies for thrombus therapy, and focus on the future design directions, challenges, and prospects in the nanomedicine application in thrombus therapy.

Selective binding of cationic fibrinogen-mimicking chitosan nanoparticles to activated platelets and efficient drug release for antithrombotic therapy

Thrombosis is the main cause of catastrophic events including ischemic stroke, myocardial infarction and pulmonary embolism. Acetylsalicylic acid (ASA) therapy offers a desirable approach to antithrombosis through a reduction of platelet reactivity. However, major bleeding complications, severe off-target side effects, and resistance or nonresponse to ASA greatly attenuate its clinical outcomes. Herein, we report a cationic fibrinogen-mimicking nanoparticle, denoted as ASA-RGD-CS@TPP, to achieve activated-platelet-targeted delivery and efficient release of ASA for safer and more effective antithrombotic therapy. This biomimetic antithrombotic system was prepared by one-pot ionic gelation between cationic arginine-glycine-aspartic acid (RGD)-grafted chitosan (RGD-CS) and anionic tripolyphosphate (TPP). The platform exhibited selective binding to activated platelets, leading to efficient release of ASA and subsequent attenuation of platelet functions, including the remarkable inhibition of platelet aggregation through a potent blockage of cyclooxygenase-1 (COX-1). After intravenous administration, ASA-RGD-CS@TPP displayed significantly prolonged circulation time and successful prevention of thrombosis in a mouse model. ASA-RGD-CS@TPP was demonstrated to significantly enhance antithrombotic therapy while showing minimal coagulation and hemorrhagic risks and excellent biocompatibility in vivo as compared to free ASA. This platform provides a simple, safe, effective and targeted strategy for the development of antithrombotic nanomedicines.

Mitochondrial Targeted Thermosensitive Nanocarrier for Near-Infrared-Triggered Precise Synergetic Photothermal Nitric Oxide Chemotherapy

Nitric oxide (NO) intervenes, that is, a potential treatment strategy, and has attracted wide attention in the field of tumor therapy. However, the therapeutic effect of NO is still poor, due to its short half-life and instability. Therapeutic concentration ranges of NO should be delivered to the target tissue sites, cell, and even subcellular organelles and to control NO generation. Mitochondria have been considered a major target in cancer therapy for their essential roles in cancer cell metabolism and apoptosis. In this study, mesoporous silicon-coated gold nanorods encapsulated with a mitochondria targeted and the thermosensitive lipid layer (AuNR@MSN-lipid-DOX) served as the carrier to load NO prodrug (BNN6) to build the near-infrared-triggered synergetic photothermal NO-chemotherapy platform (AuNR@MSN(BNN6)-lipid-DOX). The core of AuNR@MSN exhibited excellent photothermal conversion capability and high loading efficiency in terms of BNN6, reaching a high value of 220 mg/g (w/w), which achieved near-infrared-triggered precise release of NO. The outer biocompatible lipid layer, comprising thermosensitive phospholipid DPPC and mitochondrial-targeted DSPE-PEG2000-DOX, guided the whole nanoparticle to the mitochondria of 4T1 cells observed through confocal microscopy. In the mitochondria, the nanoparticles increased the local temperature over 42 °C under NIR irradiation, and a high NO concentration from BNN6 detected by the NO probe and DSPE-PEG2000-DOX significantly inhibited 4T1 cancer cells in vitro and in vivo under the synergetic photothermal therapy (PTT)-NO therapy-chemotherapy modes. The built NIR-triggered combination therapy nanoplatform can serve as a strategy for multimodal collaboration.

Remote Manipulation of TRPV1 Signaling by Near-Infrared Light-Triggered Nitric Oxide Nanogenerators for Specific Cancer Therapy

Specific activation of transient receptor potential vanilloid member 1 (TRPV1) channels provides a new avenue for cancer treatment by inducing excessive Ca2+ influx. However, controllable manipulation of TRPV1 signaling for clinical application has remained elusive due to the challenge in finding a mild and effective method of exerting external stimulus without adverse side effects in living systems. Herein, a TRPV1-targeting near-infrared (NIR) triggered nitric oxide (NO)-releasing nanoplatform (HCuS@PDA-TRPV1/BNN6) based on polydopamine (PDA) coated hollow copper sulfide nanoparticles (HCuS NPs) is developed for specific cancer therapy. Upon NIR irradiation, the NO donor BNN6 encapsulated in NIR-responsive nanovehicles can locally generate NO to activate TRPV1 channels and induce Ca2+ influx. This NIR controlled mode enables the nanoplatform to exert its therapeutic effects below the apoptotic threshold temperature (43°C), minimizing the photothermal damage to normal tissue. Integrating this special NO-mediated therapy with HCuS NPs mediated chemodynamic therapy, the designed nanoplatform exhibits a boosted anticancer activity with negligible systematic toxicity. Together, this study provides a promising strategy for site-specific cancer therapy by spatiotemporally controlled activation of surface ion channels, thus offering a solution to an unmet clinical need in cancer treatment.

Nitric oxide-releasing multifunctional catechol-modified chitosan/oxidized dextran hydrogel with antibacterial, antioxidant, and pro-angiogenic properties for MRSA-infected diabetic wound healing

The study presents a multifunctional catechol-modified chitosan (Chi-Ca)/oxidized dextran (Dex-CHO) hydrogel (CDP-PB) that possesses antibacterial, antioxidant, and pro-angiogenic properties, aimed at improving the healing of diabetic wounds. The achievement of the as-prepared CDP-PB hydrogel with superb antibacterial property (99.9 %) can be realized through the synergistic effect of phenylboronic acid-modified polyethyleneimine (PEI-PBA) and photothermal therapy (PTT) of polydopamine nanoparticles loaded with the nitric oxide (NO) donor BNN6 (PDA@BNN6). Notably, CDP-PB hydrogel achieves ∼3.6 log10 CFU/mL MRSA of inactivation efficiency under 808 nm NIR laser irradiation. In order to mitigate oxidative stress, the Chi-Ca was synthesized and afterward subjected to a reaction with Dex-CHO via a Schiff-base reaction. The catechol-containing hydrogel demonstrated its effectiveness in scavenging DPPH, •OH, and ABTS radicals (> 85 %). In addition, the cellular experiment illustrates the increased migration and proliferation of cells by the treatment of CDP-PB hydrogel in the presence of oxidative stress conditions. Moreover, the findings from the animal model experiments provide evidence that the CDP-PB hydrogel exhibited efficacy in the eradication of wound infection, facilitation of angiogenesis, stimulation of granulation, and augmentation of collagen deposition. These results indicate the potential of the CDP-PB hydrogel for use in clinical applications.

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 of nanomedicine in treatment of atherosclerosis and thrombosis

Atherosclerosis (AS) is a chronic inflammatory vascular disease. Myocardial ischemia originated from AS is the main cause of cardiovascular diseases, one of the major factors contributing to the global disease burden. AS is typically quiescent until occurrence of plaque rupture and thrombosis, leading to acute coronary syndrome and sudden death. Currently, clinical diagnostic techniques suffer from major pitfalls including lack of accuracy and specificity, which makes it rather difficult for drugs to directly target plaques to achieve therapeutic effect. Therefore, how to accurately diagnose and effectively intervene vulnerable AS plaques to achieve accurate delivery of drugs has become an urgent and evolving clinical problem. With the rapid development of nanomedicine and nanomaterials, nanotechnology has shown unique advantages in monitoring vulnerable plaques and thrombus and improving drug efficacy. Recent studies have shown that application of nanoparticle drug delivery system can booster the safety and effectiveness of drug therapy, and molecular imaging technology and nanomedicine also exhibit high clinical application potentials in disease diagnosis. Therefore, nanotechnology provides another promising avenue for diagnosis and treatment of AS and thrombosis, and has shown excellent performance in the development of targeted drug therapy and biomaterials. In this review, the research progress, challenges and prospects of nanotechnology in AS and thrombosis are discussed, expecting to provide new ideas for the prevention, diagnosis and treatment of AS and thrombosis.

Collective Behaviors of Isotropic Micromotors: From Assembly to Reconstruction and Motion Control under External Fields

Swarms of self-propelled micromotors can mimic the processes of natural systems and construct artificial intelligent materials to perform complex collective behaviors. Compared to self-propelled Janus micromotors, the isotropic colloid motors, also called micromotors or microswimmers, have advantages in self-assembly to form micromotor swarms, which are efficient in resistance to external disturbance and the delivery of large quantity of cargos. In this minireview, we summarize the fundamental principles and interactions for the assembly of isotropic active particles to generate micromotor swarms. Recent discoveries based on either catalytic or external physical field-stimulated micromotor swarms are also presented. Then, the strategy for the reconstruction and motion control of micromotor swarms in complex environments, including narrow channels, maze, raised obstacles, and high steps/low gaps, is summarized. Finally, we outline the future directions of micromotor swarms and the remaining challenges and opportunities.

Plasma-Derived Nanoclusters for Site-Specific Multimodality Photo/Magnetic Thrombus Theranostics

Traditional thrombolytic therapeutics for vascular blockage are affected by their limited penetration into thrombi, associated off-target side effects, and low bioavailability, leading to insufficient thrombolytic efficacy. It is hypothesized that these limitations can be overcome by the precisely controlled and targeted delivery of thrombolytic therapeutics. A theranostic platform is developed that is biocompatible, fluorescent, magnetic, and well-characterized, with multiple targeting modes. This multimodal theranostic system can be remotely visualized and magnetically guided toward thrombi, noninvasively irradiated by near-infrared (NIR) phototherapies, and remotely activated by actuated magnets for additional mechanical therapy. Magnetic guidance can also improve the penetration of nanomedicines into thrombi. In a mouse model of thrombosis, the thrombosis residues are reduced by ≈80% and with no risk of side effects or of secondary embolization. This strategy not only enables the progression of thrombolysis but also accelerates the lysis rate, thereby facilitating its prospective use in time-critical thrombolytic treatment.

Near-infrared-II photoacoustic imaging and photo-triggered synergistic treatment of thrombosis via fibrin-specific homopolymer nanoparticles

The formation of an occlusive thrombus in the blood vessel is the main culprit for numerous life-threatening cardiovascular diseases that represent the leading cause of morbidity and mortality worldwide. Herein, we develop a polymer nanoplatform that integrates long-wavelength second near-infrared (NIR-II) photoacoustic imaging-based thrombosis detection and antithrombotic activity. We design and synthesize a semiconducting homopolymer with strong absorption in the NIR-II region and molecular motion that boosts photothermal conversion and photoacoustic signal. We dope the homopolymer with a thermosensitive nitric oxide donor to formulate a nanoplatform, on which a fibrin-specific ligand is functionalized to ensure selective thrombus targeting. We show that with strong NIR-II light harvesting capability, bright photoacoustic signal and active thrombus accumulation ability, the NIR-II photoacoustic nanoprobes are able to sensitively and selectively delineate thrombi. We find that the nanoplatform also displays rapid and efficient blood clot removal activity with nearly complete blood flow restoration in both carotid thrombosis models and low extremity arterial thrombosis models under NIR-II light trigger by integrating a thrombus-localized photothermal effect and on-demand nitric oxide release. This nanoplatform offers a versatile approach for the diagnosis and treatment of life-threatening diseases caused by various thrombotic disorders.

Porous Molybdenum Nitride Nanosphere as Carrier-Free and Efficient Nitric Oxide Donor for Synergistic Nitric Oxide and Chemo/Sonodynamic Therapy

Given its abundant physiological functions, nitric oxide (NO) has attracted much attention as a cancer therapy. The sensitive release and great supply capacity are significant indicators of NO donors and their performance. Here, a transition metal nitride (TMN) MoN@PEG is adopted as an efficient NO donor. The release process starts with H+-triggered denitrogen owing to the high electronegativity of the N atom and weak Mo-N bond. Then, these active NHx are oxidized by O2 and other reactive oxygen species (ROS) to form NO, endowing specific release to the tumor microenvironment (TME). With a porous nanosphere structure (80 nm), MoN@PEG does not require an extra carrier for NO delivery, contributing to ultrahigh atomic utilization for outstanding release ability (94.1 ± 5.6 μM). In addition, it can also serve as a peroxidase and sonosensitizer for anticancer treatment. To further improve the charge separation, MoN-Pt@PEG was prepared to enhance the sonodynamic therapy (SDT) effect. Accordingly, ultrasound (US) further promotes NO generation due to more ROS generation, facilitating in situ peroxynitrite (·ONOO-) generation with great cytotoxicity. At the same time, the nanostructure also degrades gradually, leading to high elimination (94.6%) via feces and urine within 14-day. The synergistic NO and chemo-/sono-dynamic therapy brings prominent antitumor efficiency and further activates the immune response to inhibit metastasis and recurrence. This work develops a family of NO donors that would further widen the application of NO therapy in other fields.

NIR-II Absorbing Conjugated Polymer Nanotheranostics for Thermal Initiated NO Enhanced Photothermal Therapy

Photothermal therapy (PTT) has received constant attention as a promising cancer treatment. However, PTT-induced inflammation can limit its effectiveness. To address this shortcoming, we developed second near-infrared (NIR-II) light-activated nanotheranostics (CPNPBs), which include a thermosensitive nitric oxide (NO) donor (BNN6) to enhance PTT. Under a 1064 nm laser irradiation, the conjugated polymer in CPNPBs serves as a photothermal agent for photothermal conversion, and the generated heat triggers the decomposition of BNN6 to release NO. The combination of hyperthermia and NO generation under single NIR-II laser irradiation allows enhanced thermal ablation of tumors. Consequently, CPNPBs can be exploited as potential candidates for NO-enhanced PTT, holding great promise for their clinical translational development.

Hyperthermia-triggered NO release based on Cu-doped polypyrrole for synergistic catalytic/gas cancer therapy

Nitric oxide (NO) is a crucial gaseous medium for tumor growth and progression, but it may also cause mitochondrial disorder and DNA damage by drastically increasing its concentration in tumor. Due to its challenging administration and unpredictable release, NO based gas therapy is difficult to eliminate malignant tumor at low safe doses. To address these issues, herein, we develop a multifunctional nanocatalyst called Cu-doped polypyrrole (CuP) as an intelligent nanoplatform (CuP-B@P) to deliver the NO precursor BNN6 and specifically release NO in tumors. Under the aberrant metabolic environment of tumors, CuP-B@P catalyzes the conversion of antioxidant GSH into GSSG and excess H₂O₂ into ·OH through Cu⁺/Cu²⁺ cycle, which results in oxidative damage to tumor cells and the concomitant release of cargo BNN6. More importantly, after laser exposure, nanocatalyst CuP can absorb and convert photons into hyperthermia, which in turn, accelerates the aforesaid catalytic efficiency and pyrolyzes BNN6 into NO. Under the synergistic effect of hyperthermia, oxidative damage, and NO burst, almost complete tumor elimination is achieved in vivo with negligible toxicity to body. Such an ingenious combination of NO prodrug and nanocatalytic medicine provides a new insight into the development of NO based therapeutic strategies. STATEMENT OF SIGNIFICANCE: A hyperthermia-responsive NO delivery nanoplatform (CuP-B@P) based on Cu-doped polypyrrole was designed and fabricated, in which CuP catalyzed the conversion of H₂O₂ and GSH into ·OH and GSSG to induce intratumoral oxidative damage. After laser irradiation, hyperthermia ablation and responsive release of NO further coupled with oxidative damage to eliminate malignant tumors. This versatile nanoplatform provides new insights into the combined application of catalytic medicine and gas therapy.

In vivo applications of micro/nanorobots

Untethered robots in the size range of micro/nano-scale offer unprecedented access to hard-to-reach areas of the body. In these challenging environments, autonomous task completion capabilities of micro/nanorobots have been the subject of research in recent years. However, most of the studies have presented preliminary in vitro results that can significantly differ under in vivo settings. Here, we focus on the studies conducted with animal models to reveal the current status of micro/nanorobotic applications in real-world conditions. By a categorization based on target locations, we highlight the main strategies employed in organs and other body parts. We also discuss key challenges that require interest before the successful translation of micro/nanorobots to the clinic.

Chiral Ruthenium Nanozymes with Self-Cascade Reaction Driven the NO Generation Induced Macrophage M1 Polarization Realizing the Lung Cancer "Cocktail Therapy"

Macrophages as the main cause of cancer immunosuppression, how to effectively induce macrophage M1 polarization remain the major challenge in lung cancer therapy. Herein, inspired by endogenous reactions, a strategy is proposed to coactivate macrophage M1 polarization by reactive oxygen species (ROS) and nitric oxide (NO) with self-autocatalytic cascade reaction. To enhance the generation of NO and ROS, NO Precursor-Arginine as capping agents for inducing synthesis two kinds of chiral ruthenium nanozyme (D/L-Arginine@Ru). Under the properties of Ru nanozymes through synchronously mimicking the activity of oxidase and nitric oxide synthase (NOS), chiral Ru nanozyme can rapidly generate ¹ O₂ and O₂ at first stage, and then catalyze Arginine to produce sufficient NO, thus enhance macrophage M1 polarization to reverse tumor immunosuppression. Moreover, combination the antitumor activity of ¹ O₂ , NO, the chiral Ru nanozymes realize the "cocktail therapy" by inducing tumor cell apoptosis as well as ferroptosis. In addition, the chirality influences the bioactivity of Ru nanozymes that L-Arginine@Ru shows the better therapeutic effect with stronger catalytic activity and natural homology. It is hoped the high performance of chiral Ru nanozyme with "cocktail therapy" is an effective therapeutic reagent and can provide a feasible treatment strategy for tumor catalytic therapy.

Highly Penetrable Drug-Loaded Nanomotors for Photothermal-Enhanced Ferroptosis Treatment of Tumor

A kind of drug-loaded nanomotors with deep penetration was developed to improve the therapeutic effect of ferroptosis on tumor. The nanomotors were constructed by co-loading hemin and ferrocene (Fc) on the surface of bowl-shaped polydopamine (PDA) nanoparticles. The near-infrared response of PDA makes the nanomotor have high tumor penetration capability. In vitro experiments show that the nanomotors can exhibit good biocompatibility, high light to heat conversion efficiency, and deep tumor permeability. It is worth noting that under the catalysis of H2O2 overexpressed in the tumor microenvironment, the Fenton-like reagents hemin and Fc loaded on the nanomotors can increase the concentration of toxic •OH. Furthermore, hemin can consume glutathione in tumor cells and trigger the up-regulation of heme oxygenase-1, which can efficiently decompose hemin to Fe2+, thus producing the Fenton reaction and causing a ferroptosis effect. Notably, thanks to the photothermal effect of PDA, it can enhance the generation of reactive oxygen species and thus intervene in the Fenton reaction process, thereby enhancing the ferroptosis effect photothermally. In vivo antitumor results show that the drug-loaded nanomotors with high penetrability showed an effective antitumor therapeutic effect.

Radiopaque Nanorobots as Magnetically Navigable Contrast Agents for Localized In Vivo Imaging of the Gastrointestinal Tract

Magnetic nanorobots offer wireless navigation capability in hard-to-reach areas of the human body for targeted therapy and diagnosis. Though in vivo imaging is required for guidance of the magnetic nanorobots toward the target areas, most of the imaging techniques are inadequate to reveal the potential locomotion routes. This work proposes the use of radiopaque magnetic nanorobots along with microcomputed tomography (microCT) for localized in vivo imaging applications. The nanorobots consist of a contrast agent, barium sulfate (BaSO₄ ), magnetized by the decoration of magnetite (Fe₃ O₄ ) particles. The magnetic features lead to actuation under rotating magnetic fields and enable precise navigation in a microfluidic channel used to simulate confined spaces of the body. In this channel, the intrinsic radiopacity of the nanorobots also provides the possibility to reveal the internal structures by X-ray contrast. Furthermore, in vitro analysis indicates nontoxicity of the nanorobots. In vivo experiments demonstrate localization of the nanorobots in a specific part of the gastrointestinal (GI) tract upon the influence of the magnetic field, indicating the efficient control even in the presence of natural peristaltic movements. The nanorobots reported here highlight that smart nanorobotic contrast agents can improve the current imaging-based diagnosis techniques by providing untethered controllability in vivo.

Application of Nanotechnology in Thrombus Therapy

A thrombus is a blood clot that forms in the lumen of an artery or vein, restricting blood flow and causing clinical symptoms. Thrombosis is associated with many life-threatening cardiovascular diseases. However, current clinical therapeutic technologies still have many problems in targeting, enrichment, penetration, and safety to meet the thrombosis treatment needs. Therefore, researchers devote themselves to developing nanosystems loaded with antithrombotic drugs to address this paradox in recent years. Herein, the existing thrombosis treatment technologies are first reviewed; and then, their advantages and disadvantages are outlined based on a brief discussion of thrombosis's definition and formation mechanism. Furthermore, the need and application cases for introducing nanotechnology are discussed, focusing on thrombus-specific targeted ligand modification technology and microenvironment-triggered responsive drug release technology. Then, nanomaterials that can be used to design antithrombotic nanotherapeutic systems are summarized. Moreover, a variety of drug delivery technologies driven by nanomotors in thrombosis therapy is also introduced. Last of all, a prospective discussion on the future development of nanotechnology for thrombosis therapy is highlighted.

Molecularly self-fueled nano-penetrator for nonpharmaceutical treatment of thrombosis and ischemic stroke

Thrombotic cerebro-cardiovascular diseases are the leading causes of disability and death worldwide. However, current drug therapeutics are compromised by narrow therapeutic windows, unsatisfactory thrombolysis effects, severe bleeding events, and high recurrence rates. In this study, we exploit a self-propelling nano-penetrator with high fuel loading and controllable motion features, which is molecularly co-assembled using a photothermal photosensitizer (DiR) and a photothermal-activable NO donor (BNN6). The precisely engineered nano-penetrator of the BNN6-DiR fuel pair shows distinct advantages in terms of NO productivity and autonomous motion under laser irradiation. In animal models of artery/vein thrombosis and acute ischemic stroke, the self-fueled nano-penetrator enables self-navigated thrombus-homing accumulation, self-propelled clot deep penetration, fluorescence image-guided photothermal/mechanical thrombolysis, and NO-mediated prevention of thrombosis recurrence and acute ischemic stroke salvage. As expected, the molecularly self-fueled nano-penetrator displayed favorable therapeutic outcomes without bleeding risk compared to the clinically available thrombolytic drug. This study offers a facile, safe, and effective nonpharmaceutical modality towards the clinical treatment of thrombosis and ischemic stroke.

Hydrogen Bonding Nanoarchitectonics of Organic Pigment-Based Janus Microrobots with Entering Capability into Cancer Cells

Autonomous microrobots are at the forefront of biomedical research as they are expected to be applied for specific tasks at the intracellular level such as cargo delivery, sensing, molecular manipulation, among others. Here, we report on a preparation of microrobots based on quinacridone and indigo, which are members of the organic hydrogen-bonded pigment family. The microrobots were fabricated by asymmetric platinum deposition on corresponding quinacridone and indigo microparticles that possessed a homogeneous size and shape distribution. The microrobots exhibited autonomous locomotion in the presence of hydrogen peroxide, which was further supported by UV irradiation. The organic pigment-based microrobots were studied in the presence of mouse colorectal carcinoma cells, and it was observed that they were internalized into the cells. Internalization was visualized using confocal laser scanning microscopy. This study reveals the possibility of fabricating hydrogen-bonded organic pigment-based microrobots for biomedical applications by employing the principles of nanoarchitectonics.

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.

Self-Propelled Nanomotors with an Alloyed Engine for Emergency Rescue of Traumatic Brain Injury

In severe traumatic brain injury (sTBI), acute oxidative stress and inflammatory cascades rapidly spread to cause irreversible brain damage and low survival rate within minutes. Therefore, developing a feasible solution for the quick-treatment of life-threatening emergency is urgently demanded to earn time for hospital treatment. Herein, Janus catalysis-driven nanomotors (JCNs) are carefully constructed via plasma-induced alloying technology and sputtering-caused half-coating strategy. The theoretical calculation and experiment results indicate that the heteroatom-doping alloyed engine endows JCNs with much higher catalytic activity for removing reactive oxygen species and reactive nitrogen species than common Pt-based engines. When JCNs are dropped to the surface of the ruptured skull, they can effectively catalyze endogenous hydrogen peroxide, which induces movement as fuels to promote JCNs to deep brain lesions for further nanocatalyst-mediated cascade-blocking therapy. The results demonstrate that the JCNs successfully block the inflammatory cascades, thereby reversing multiple behavioral defects and dramatically declining the mortality of sTBI mice. This work provides a revolutionary nanomotor-based strategy to sense brain injury and scavenge oxidative stress. Meanwhile, the JCNs provide a feasible strategy to adapt various first-aid scenarios due to their self-propelled movement combined with highly multienzyme-like catalytic activity, exhibiting tremendous therapeutic potential to help people for emergency pretreatment.

Biomimetic Bacteriophage-Like Particles Formed from Probiotic Extracts and NO Donors for Eradicating Multidrug-Resistant Staphylococcus aureus

Effectively clearing multidrug-resistant bacteria through nonantibiotic treatments is crucial for the recovery of infected tissues in favorable biological environments. Herein, a thermally responsive donor of cell-messenger nitric oxide (NO) is combined with extracts of food-grade Lactobacillus casei to form biomimetic phage-like microparticles with a tailspike structure. These particles can invade bacterial membranes and release NO to disrupt nitrogen and respiratory metabolisms, which initiates the programmed death of multidrug-resistant Staphylococcus aureus (MRSA) for inducing lysis, like the bacterial virus. Experiments suggest that these microparticles can also weaken bacterial toxicity and provide favorable conditions for cell proliferation because of the continuously released NO. By encapsulating these microparticles into graphene-oxide-doped polymers, a dual-mode antibacterial hydrogel (DMAH) can be constructed. In vivo results reveal that the DMAH achieves a long-time sterilization of MRSA with 99.84 ± 0.13% antibacterial rate in the dark because of the phage-like performance of the biomimetic microparticles. In its other antibacterial mode, DMAH subjected to 20 min of near-infrared irradiation release NO, which, together with the photothermal effect, synergistically damages bacterial cell membranes to achieve very fast disinfection (97.13 ± 0.41% bactericidal rate). This multifunctional hydrogel can also significantly accelerate wound healing due to the phage-like particles.

Bacteria-Templated and Dual Enzyme-Powered Microcapsule Motors To Promote Thrombus Penetration and Thrombolytic Efficacy

Antithrombotic therapy is confronted with short half-lives of thrombolytic agents and high bleeding risks. Challenges remain in the development of drug delivery systems for thorough destruction of thrombi and timely restoration of blood flow while minimizing side effects. Herein, polydopamine capsule-like micromotors with urokinase (uPA) loadings and Arg-Gly-Asp (RGD) grafts (r-u@PCM) were constructed using rod-shaped bacteria as the template, and one single opening was created on each capsule through bacterial ghost (BG) formation. Glucose oxidase and catalase were encapsulated in the large cavity of microcapsules, and their successive oxidation of glucose produced O₂ bubbles, which ejected out through the single opening to propel the motion of r-u@PCM. In vitro targeting testing of r-u@PCM shows significant higher accumulations on the activated platelets than those without RGD grafts (u@PCM, 7 folds) or without enzyme loadings (r-u@PC, 11 folds). Compared with the major distribution of r-u@PC on the clot surface, r-u@PCM efficiently penetrates into clots with dense fibrin networks, and near-infrared (NIR) irradiation (r-u@PCM/NIR) promotes thrombus infiltration through increasing uPA release and thermolysis of the networks. Pharmacokinetic study shows that the loading of uPA in r-u@PCM extends the terminal half-life from 24 min to 5.5 h and the bioavailability increased 13 times. In a hindlimb venous thrombosis model, r-u@PCM/NIR treatment promotes uPA accumulations in thrombi and disrupts all the thrombi after 8 h with a full recovery of blood flows. Effective thrombolysis is also achieved even after reducing the uPA dose 5 times. Thus, this is the first attempt to fabricate rod-shaped microcapsule motors through a biologically derived method, including bacterial templating and BG formation-induced opening generation. r-u@PCM/NIR treatment promotes thrombolysis through the photothermal effect, self-propelled infiltration into thrombi, and accelerated local release of uPA, providing a prerequisite for reducing uPA dose and bleeding side effects.

Synergistic Integration and Pharmacomechanical Function of Enzyme-Magnetite Nanoparticle Swarms for Low-Dose Fast Thrombolysis

Magnetic micro-/nanoparticles are extensively explored over the past decade as active diagnostic/therapeutic agents for minimally invasive medicine. However, sufficient function integration on these miniaturized bodies toward practical applications remains challenging. This work proposes a synergistic strategy via integrating particle functionalization and bioinspired swarming, demonstrated by recombinant tissue plasminogen activator modified magnetite nanoparticles (rtPA-Fe₃ O₄ NPs) for fast thrombolysis in vivo with low drug dosage. The synthesized rtPA-Fe₃ O₄ NPs exhibit superior magnetic performance, high biocompatibility, and thrombolytic enzyme activity. Benefiting from a customized magnetic operation system designed for animal experiments and preclinical development, these agglomeration-free NPs can assemble into micro-/milli-scale swarms capable of robust maneuver and reconfigurable transformation for on-demand tasks in complex biofluids. Specifically, the spinning mode of the swarm exerts focused fluid shear stresses while rubbing on the thrombus surface, constituting a mechanical force for clot breakdown. The synergy of the NPs' inherent enzymatic effect and swarming-triggered fluid forces enables amplified efficacy of thrombolysis in an in vivo occlusion model of rabbit carotid artery, using lower drug concentration than clinical dosage. Furthermore, swarming-enhanced ultrasound signals aid in imaging-guided treatment. Therefore, the pharmacomechanical NP swarms herein represent an injectable thrombolytic tool joining advantages of intravenous drug therapy and robotic intervention.

Near-infrared laser-controlled nitric oxide-releasing gold nanostar/hollow polydopamine Janus nanoparticles for synergistic elimination of methicillin-resistant Staphylococcus aureus and wound healing

Recently, nitric oxide (NO) has received increasing interest in combat against bacteria-induced infections because of its ability to sensitize and enhance the antibacterial effectiveness of many therapeutic approaches such as antibiotics. However, high-efficient loading and controlled release of NO remain a big challenge. In the present work, a type of gold nanostar/hollow polydopamine Janus nanostructure (GNS/HPDA JNPs) with precise near infrared (NIR)-controlled NO release property was fabricated using a facile seed-mediated method. Upon NIR laser irradiation, the NO-releasing GNS/HPDA JNPs (GNS/HPDA-BNN6) exhibited a synergistic photothermal and NO antibacterial effect by significantly inhibiting the growth and biofilm formation of both Gram-negative and Gram-positive bacterial strains, including methicillin-resistant Staphylococcus aureus (MRSA). An in-depth mechanism study revealed that two pathways were mainly involved in the synergistic photothermal and NO antibacterial effect. In one pathway, the synergistic effect severely destroyed the bacterial membrane by causing leakage of intracellular components such as DNA. In another pathway, the synergistic effect largely disturbed bacterial metabolism by regulating relative metabolic genes, followed by enhancing ROS generation to cause intracellular GSH depletion and DNA damage. More importantly, the synergistic effect significantly diminished the drug resistance of MRSA by downregulating the expression of the drug-resistant gene mecA and some relative multidrug efflux pumps (e.g., SepA and Tet38). An in vivo evaluation using a rat model with MRSA-infected wounds indicated that the synergistic photothermal and NO effect of GNS/HPDA-BNN6 can effectively eliminate MRSA from wounds, thereby alleviating inflammation and promoting wound healing. STATEMENT OF SIGNIFICANCE: Multidrug-resistant (MDR) bacteria have become a big threat to mankind, and therefore, the development of innovative antibacterial agents with high antibacterial efficiency is urgently required. Nanomaterial-mediated nitric oxide (NO) therapy is a promising strategy to effectively combat MDR bacteria through a synergistic antibacterial effect. Here, a gold nanostar/hollow polydopamine Janus nanostructure with precise near infrared (NIR) light-controlled NO release property (GNS/HPDA-BNN6) was developed. Both in vitro and in vivo evaluations demonstrated that GNS/HPDA-BNN6 could effectively eliminate methicillin-resistant Staphylococcus aureus (MRSA) from infected wounds and promote wound healing through a synergistic photothermal and NO therapeutic effect. Remarkably, the synergistic effect significantly diminished the drug resistance of MRSA by downregulating the expression of some drug-resistant genes and multidrug efflux pumps.

Bacteria-propelled microtubular motors for efficient penetration and targeting delivery of thrombolytic agents

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

Carrier-Free Trehalose-Based Nanomotors Targeting Macrophages in Inflammatory Plaque for Treatment of Atherosclerosis

Inducing autophagy of macrophages to improve abnormal lipid metabolism is an important way to treat atherosclerosis (AS). Yet, the current application of the mammalian target of rapamycin (mTOR)-dependent autophagy inducers is limited by the side effects and lack of targeting and low biological availability. Herein, a kind of nitric oxide (NO)-driven carrier-free nanomotor based on the reaction between trehalose (Tr, one of the mTOR-independent autophagy inducers), L-arginine (Arg), and phosphatidylserine (PS) is reported. The developed nanomotors use NO as the driving force, which is generated from the reaction between Arg and excessive reactive oxygen species (ROS) and inducible nitric oxide synthase (iNOS) specifically presenting in the AS microenvironment. The high expression of ROS and iNOS in the AS site can be used as chemoattractants to induce chemotaxis behavior of the nanomotors to achieve the first-step targeting an AS plaque. Subsequently, the "eat me" signal sent by PS is exploited to precisely target to the macrophages in the AS plaque, realizing the plaque-macrophage-targeted effect by this step-by-step strategy. In vitro and in vivo results confirm that the introduction of the concept of carrier-free nanomotors has greatly improved the biological availability of trehalose (the dose can be reduced from 2.5 g kg^-1 in previous reports to 0.01 g kg^-1 in this work). Particularly, consumed ROS and the production of NO during the targeting process also play positive roles, in which the former regulates the M2 polarization of macrophages and the latter promotes the reconstruction of an endothelial barrier, which contributes to the multilink treatment of AS.

Tumor-specific nitric oxide generator to amplify peroxynitrite based on highly penetrable nanoparticles for metastasis inhibition and enhanced cancer therapy

Multiple biological barriers and tumor metastasis severely impede the tumor therapy. To address these adversities, an acid-activated poly (ethylene glycol)-poly-l-lysine-2,3-dimethylmaleic anhydride/poly (ε-caprolactone)-poly(l-arginine)/β-lapachone nanoparticles (mPEG-PLL-DMA/PCL-P(L-arg)/β-Lap, PLM/PPA/β-Lap NPs) were constructed with charge-reversal and size-reduction for β-Lap delivery with a cascade reaction of reactive oxygen species (ROS) and nitric oxide (NO) production. The nanosystem exhibited highly penetrable, superior cellular uptake and desirable endo-lysosomal escape thanks to size-reduction, charge-reversal and proton sponge, respectively. The vast bulk of ROS, which rapidly generated from β-Lap under high concentration quinone oxidoreductase 1 (NQO1), catalyzed guanidine groups to produce NO and generated highly toxic peroxynitrite (ONOO^-). ONOO^- would activate pro-matrix metalloproteinases (pro-MMPs) to generate MMPs, degrade the dense extracellular matrix (ECM) to augment the penetration capability, and aggravate DNA damage. NO and ONOO^- influenced mitochondrial function by decreasing mitochondrial membrane potential and prevented the production of adenosine triphosphate (ATP), which inhibited the ATP-dependent tumor-derived microvesicles (TMVs) and restrained tumor metastasis. NO was defined as an epithelial mesenchymal transition (EMT) inhibitor to restrain tumor metastasis. All consequences demonstrated that PLM/PPA/β-lap NPs exhibited efficient penetration capability, outstanding anti-metastasis activity and favorable antitumor efficacy. Those novel acid-activated NPs are intended to provide further inspiration for multifunctional NO gas therapy.

Upconversion nanoparticles regulated drug & gas dual-effective nanoplatform for the targeting cooperated therapy of thrombus and anticoagulation

Thromboembolism is the leading cause of cardiovascular mortality. Currently, for the lack of targeting, short half-life, low bioavailability and high bleeding risk of the classical thrombolytic drugs, pharmacological thrombolysis is usually a slow process based on micro-pumping. In addition, frequently monitoring and regulating coagulation functions are also required during (and after) the process of thrombolysis. To address these issues, a targeted thrombolytic and anticoagulation nanoplatform (UCATS-UK) is developed based on upconversion nanoparticles (UCNPs) that can convert 808 or 980 nm near-infrared (NIR) light into UV/blue light. This nanoplatform can target and enrich in the thrombus site. Synergistic thrombolysis and anticoagulation therapy thus could be realized through the controlled release of urokinase (UK) and nitric oxide (NO). Both in vitro and in vivo experiments have confirmed the excellent thrombolytic and anticoagulative capabilities of this multifunctional nanoplatform. Combined with the unique fluorescent imaging capability of UCNPs, this work is expected to contribute to the development of clinical thrombolysis therapy towards an integrated system of imaging, diagnosis and treatment.

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This work is not only the first application of UCNPs in the thrombolysis therapy, but also the first attempt to develop a dual effective drug & gas nanoplatform for thrombolytic & anticoagulation therapy.

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Besides conventional in vitro and animal experiments, a 3D printed vascular model is also constructed to further verify the feasibility of UCATS-UK.

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Through surface chemical modification, the nanoplatform possesses the capabilities of targeting thrombus, as well as light-controlled NO release for drug-free anticoagulation therapy.

Enzyme Catalysis Biomotor Engineering of Neutrophils for Nanodrug Delivery and Cell-Based Thrombolytic Therapy

Utilizing neutrophils (NEs) to target and deliver nanodrugs to inflammation sites has received considerable attention. NEs are involved in the formation and development of thrombosis by transforming into neutrophil extracellular traps (NETs); this indicates that NEs may be a natural thrombolytic drug delivery carrier. However, NEs lack an effective power system to overcome blood flow resistance and enhance targeting efficiency. Herein, we report the application of a urease catalysis micromotor powered NEs nanodrug delivery system to promote thrombolysis and suppress rethrombosis. The urease micromotor powered Janus NEs (UM-NEs) were prepared by immobilizing the enzyme asymmetrically onto the surface of natural NEs and then loading urokinase (UK) coupled silver (Ag) nanoparticles (Ag-UK) to obtain the UM-NEs (Ag-UK) system. Urease catalytic endogenous urea is used to generate thrust by producing ammonia and carbon dioxide, which propels NEs actively targeting the thrombus. The UM-NEs (Ag-UK) can be activated by enriched inflammatory cytokines to release NETs at the thrombosis site, resulting in a concomitant release of Ag-UK. Ag-UK induces thrombolysis to restore vascular recanalization. This urease micromotor-driven NEs drug delivery system can significantly reduce the hemorrhagic side effects, promote thrombolysis, and inhibit rethrombosis with high bioavailability and biosafety, which can be used for the treatment of thrombotic diseases.

Elaborately Engineering a Self-Indicating Dual-Drug Nanoassembly for Site-Specific Photothermal-Potentiated Thrombus Penetration and Thrombolysis

Thrombotic cardio-cerebrovascular diseases seriously threaten human health. Currently, conventional thrombolytic treatments are challenged by the low utilization, inferior thrombus penetration, and high off-target bleeding risks of most thrombolytic drugs, resulting in unsatisfactory treatment outcomes. Herein, it is proposed that these challenges can be overcome by precisely integrating the conventional thrombolytic strategy with photothermal therapy. After co-assembly engineering optimization, a fibrin-targeting peptide-decorated nanoassembly of DiR (a photothermal probe) and ticagrelor (TGL, an antiplatelet drug) is prepared for thrombus-homing delivery, abbreviated as FT-DT NPs. The elaborately engineered nanoassembly shows multiple advantages, including simple preparation with high drug co-loading capacity, synchronous delivery of two drugs with long systemic circulation, thrombus-targeted accumulation with self-indicating function, as well as photothermal-potentiated thrombus penetration and thrombolysis with high therapeutic efficacy. As expected, FT-DT NPs not only show bright fluorescence signals in the embolized vessels, but also perform photothermal/antiplatelet synergistic thrombolysis in vivo. This study offers a simple and versatile co-delivery nanoplatform for imaging-guided photothermal/antiplatelet dual-modality thrombolysis.

Towards micromachine intelligence: potential of polymers

Inspired by the increasing desire to mimic the perfection of nature, micro- and nanorobots are triggering increasing interest among the scientific community. The development of such tiny machines that can autonomously perform specific and various tasks at a small scale has reached a high-level of complexity over the last 15 years although the transition from hard to soft self-propelled architectures has had the most profound impact. The use of organic components, such as polymers, is of particular interest to fulfill the lack of biocompatibility and biodegradability of inorganic-based microrobots. Additionally, the combination of self-powered micro- and nanorobots with some macromolecules' ability to be deformed and respond to external stimuli is an important topic. This review aims to critically assess the fundamental aspects of smart machines composed of polymers, examine recent advances in the combined systems at the micro- and nanoscale, and discuss the specific contribution of several polymer families. This review elucidates the role of smart polymers in the expanding field of intelligent micromachines.

Stimulus-responsive nanomaterials under physical regulation for biomedical applications

Cancer is a growing threat to human beings. Traditional treatments for malignant tumors usually involve invasive means to healthy human tissues, such as surgical treatment and chemotherapy. In recent years the use of specific stimulus-responsive materials in combination with some non-contact, non-invasive stimuli can lead to better efficacy and has become an important area of research. It promises to develop personalized treatment systems for four types of physical stimuli: light, ultrasound, magnetic field, and temperature. Nanomaterials that are responsive to these stimuli can be used to enhance drug delivery, cancer treatment, and tissue engineering. This paper reviews the principles of the stimuli mentioned above, their effects on materials, and how they work with nanomaterials. For this aim, we focus on specific applications in controlled drug release, cancer therapy, tissue engineering, and virus detection, with particular reference to recent photothermal, photodynamic, sonodynamic, magnetothermal, radiation, and other types of therapies. It is instructive for the future development of stimulus-responsive nanomaterials for these aspects.

Guiding Drug Through Interrupted Bloodstream for Potentiated Thrombolysis by C-Shaped Magnetic Actuation System In Vivo

Fast and effective thrombolysis using tissue plasminogen activator (tPA) is limited by the poor delivery efficiency of thrombolytic drugs, which is induced by an interrupted bloodstream and delayed recanalization. Existing magnetic micro/nanodrug-loaded robots used for targeted thrombotic therapy are limited by the complexity of the clinical verification of nanodrugs and the limited space of magnetic actuation systems. Herein, a general drug delivery strategy based on mass transportation theory for thrombolysis is presented, and an open space C-shaped magnetic actuation system with laser location and ultrasound imaging navigation for in vivo evaluation is developed. tPA can be guided through an interrupted bloodstream to the thrombi by the locomotion of magnetic nanoparticle swarms (MNSs), thereby improving the thrombolysis efficacy. Notably, this strategy is able to quickly establish a life channel to achieve time-critical recanalization, which is typically inaccessible using native tPA. Both in vitro and in vivo thrombolysis experiments demonstrate that the thrombus lysis efficacy significantly increases after the application of the MNS under a rotating magnetic field. This study provides an anticipated C-shaped magnetic actuation system for in vivo validation and also presents a clinically feasible drug delivery strategy for targeted thrombolytic therapy with minimal systemic tPA exposure.

Multifunctional micro/nanomotors as an emerging platform for smart healthcare applications

Self-propelling micro- and nano-motors (MNMs) are emerging as a multifunctional platform for smart healthcare applications such as biosensing, bioimaging, and targeted drug delivery with high tissue penetration, stirring effect, and rapid drug transport. MNMs can be propelled and/or guided by chemical substances or external stimuli including ultrasound, magnetic field, and light. In addition, enzymatically powered MNMs and biohybrid micromotors have been developed using the biological components in the body. In this review, we describe emerging MNMs focusing on their smart propulsion systems, and diagnostic and therapeutic applications. Finally, we highlight several MNMs for in vivo applications and discuss the future perspectives of MNMs on their current limitations and possibilities toward further clinical applications.

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.

Light-Activated Biodegradable Covalent Organic Framework-Integrated Heterojunction for Photodynamic, Photothermal, and Gaseous Therapy of Chronic Wound Infection

Chronic wound healing, impeded by bacterial infections and drug resistance, poses a threat to global human health. Antibacterial phototherapy is an effective way to fight microbial infection without causing drug resistance. Covalent organic frameworks (COFs) are a class of highly crystalline functional porous carbon-based materials composed of light atoms (e.g., carbon, nitrogen, oxygen, and borane), showing potential applications in the biomedical field. Herein, we constructed porphyrin-based COF nanosheets (TP-Por CON) for synergizing photodynamic and photothermal therapy under red light irradiation (e.g., 635 nm). Moreover, a nitric oxide (NO) donor molecule, BNN6, was encapsulated into the pore volume of the crystalline porous framework structure to moderately release NO triggered by red light irradiation for realizing gaseous therapy. Therefore, we successfully synthesized a novel TP-Por CON@BNN6-integrated heterojunction for thoroughly killing Gram-negative bacteria Escherichia coli and Gram-positive bacteria Staphylococcus aureus in vitro. Our research identified that TP-Por CON@BNN6 has favorable biocompatibility and biodegradability, low phototoxicity, anti-inflammatory properties, and excellent mice wound healing ability in vivo. This study indicates that the TP-Por CON@BNN6-integrated heterojunction with multifunctional properties provides a potential strategy for COF-based gaseous therapy and microorganism-infected chronic wound healing.

Near-Infrared Light and Upconversion Nanoparticle Defined Nitric Oxide-Based Osteoporosis Targeting Therapy

Osteoporosis is one of the most common diseases affecting bone metabolism. Nitric oxide (NO), an endogenous gas molecule involved in osteogenesis, can effectively promote the proliferation and differentiation of osteoblasts. Although exogenous NO can reverse osteoporosis to a certain extent, the transitory half-life and short diffusion radius of NO severely limit its application. In this work, a gas generation nanoplatform of NO with bone targeting property (UCPA) is developed based on the upconversion nanoparticles (UCNPs) that can convert 808 nm near-infrared (NIR) light into UV/blue light, and further stimulate the NO donor (BNN) to release NO. With an adjustment of the output power of the 808 nm NIR, the amount of released NO can be precisely controlled. Both in vitro and in vivo experiments demonstrate the favorable affinity of UCPA to bone due to the modification of alendronate; thus, it can directly release NO in bone and reverse osteoporosis. In addition, the cellular uptake of nanocomposites and intracellular NO release can be observed in preosteoblasts, thereby promoting their differentiation efficiently.