Platelet membrane-functionalized nanoparticles with improved targeting ability and lower hemorrhagic risk for thrombolysis therapy

Thrombotic microenvironment responsive crosslinking cyclodextrin metal-organic framework nanocarriers for precise targeting and thrombolysis

Global public health is seriously threatened by thrombotic disorders because of their high rates of mortality and disability. Most thrombolytic agents, especially protein-based pharmaceuticals, have a short half-life in circulation, reducing their effectiveness in thrombolysis. The creation of an intelligent drug delivery system that delivers medication precisely and releases it under regulated conditions at nearby thrombus sites is essential for effective thrombolysis. In this article, we present a unique medication delivery system (MCRUA) that selectively targets platelets and releases drugs by stimulation from the thrombus' microenvironment. The thrombolytic enzyme urokinase-type plasminogen-activator (uPA) and the anti-inflammatory medication Aspirin (acetylsalicylic acid, ASA) are both loaded onto pH-sensitive CaCO3/cyclodextrin crosslinking metal-organic frameworks (MC) that make up the MCRUA system. c(RGD) is functionalized on the surface of MC, which is functionalized by RGD to an esterification reaction. Additionally, the thrombus site's acidic microenvironment causes MCRUA to disintegrate to release uPA for thrombolysis and aiding in vessel recanalization. Moreover, cyclodextrin-encapsulated ASA enables the treatment of the inflammatory environment within the thrombus, enhancing the antiplatelet aggregation effects and promoting cooperative thrombolysis therapy. When used for thrombotic disorders, our drug delivery system (MCRUA) promotes thrombolysis, suppresses rethrombosis, and enhances biosafety with fewer hemorrhagic side effects.

All-stage targeted red blood cell membrane-coated docetaxel nanocrystals for glioma treatment

Challenges for glioma treatment with nanomedicines include physio-anatomical barriers (the blood-brain barrier and blood-brain tumor barrier), low drug loading capacity, and limited circulation time. Here, a red blood cell membrane-coated docetaxel drug nanocrystal (pV-RBCm-NC(DTX)), modified with pHA-VAP (pV) for all-stage targeting of glioma, was designed. The NC(DTX) core exhibited a high drug loading capacity but low in vivo stability, and the RBCm coating significantly enhanced the stability and prolonged in vivo circulation. Moreover, the Y-shaped targeting ligand pV was modified by a mild avidin-biotin interaction, which endowed RBCm-NC(DTX) with superior barrier-crossing ability and therapeutic efficacy. The integration of nanocrystal technology, cell membrane coating, and the avidin-biotin insertion method into this active targeting biomimetic formulation represents a promising drug delivery strategy for glioma.

Advanced Nano-Drug Delivery Systems in the Treatment of Ischemic Stroke

In recent years, the frequency of strokes has been on the rise year by year and has become the second leading cause of death around the world, which is characterized by a high mortality rate, high recurrence rate, and high disability rate. Ischemic strokes account for a large percentage of strokes. A reperfusion injury in ischemic strokes is a complex cascade of oxidative stress, neuroinflammation, immune infiltration, and mitochondrial damage. Conventional treatments are ineffective, and the presence of the blood-brain barrier (BBB) leads to inefficient drug delivery utilization, so researchers are turning their attention to nano-drug delivery systems. Functionalized nano-drug delivery systems have been widely studied and applied to the study of cerebral ischemic diseases due to their favorable biocompatibility, high efficiency, strong specificity, and specific targeting ability. In this paper, we briefly describe the pathological process of reperfusion injuries in strokes and focus on the therapeutic research progress of nano-drug delivery systems in ischemic strokes, aiming to provide certain references to understand the progress of research on nano-drug delivery systems (NDDSs).

An Ultrasmall Cu/Cu2O Nanoparticle-Based Diselenide-Bridged Nanoplatform Mediating Reactive Oxygen Species Scavenging and Neuronal Membrane Enhancement for Targeted Therapy of Ischemic Stroke

Ischemic stroke is one of the major causes of death and disability worldwide, and an effective and timely treatment of ischemic stroke has been a challenge because of the narrow therapeutic window and the poor affinity with thrombus of the thrombolytic agent. In this study, rPZDCu, a multifunctional nanoparticle (NP) with the effects of thrombolysis, reactive oxygen species (ROS) scavenging, and neuroprotection, was synthesized based on an ultrasmall Cu4.6O NP, the thrombolytic agent rt-PA, and docosahexaenoic acid (DHA), which is a major component of the neuronal membrane. rPZDCu showed strong thrombus-targeting ability, which was achieved by the platelet cell membrane coating on the NP surface, and a good thrombolytic effect in both the common carotid artery clot model and embolic middle cerebral artery occlusion (MCAO) model of rats. Furthermore, rPZDCu exhibited a good escape from the phagocytosis of macrophages, effective promotion of the polarization of microglia, and efficient recovery of neurobiological and behavioral functions in the embolic MCAO model of rats. This is a heuristic report of (1) the Cu0/Cu+ NP for the treatments of brain diseases, (2) the integration of DHA and ROS scavengers for central nervous system therapies, and (3) diselenide-based ROS-responsive NPs for ischemic stroke treatments. This study also offers an example of cell membrane-camouflaged stimuli-responsive nanomedicine for brain-targeting drug delivery.

Engineering Platelet Membrane Imitating Nanoparticles for Targeted Therapeutic Delivery

Platelet Membrane Imitating Nanoparticles (PMINs) is a novel drug delivery system that imitates the structure and functionality of platelet membranes. PMINs imitate surface markers of platelets to target specific cells and transport therapeutic cargo. PMINs are engineered by incorporating the drug into the platelet membrane and encapsulating it in a nanoparticle scaffold. This allows PMINs to circulate in the bloodstream and bind to target cells with high specificity, reducing off-target effects and improving therapeutic efficacy. The engineering of PMINs entails several stages, including the separation and purification of platelet membranes, the integration of therapeutic cargo into the membrane, and the encapsulation of the membrane in a nanoparticle scaffold. In addition to being involved in a few pathological conditions including cancer, atherosclerosis, and rheumatoid arthritis, platelets are crucial to the body's physiological processes. This study includes the preparation and characterization of platelet membrane-like nanoparticles and focuses on their most recent advancements in targeted therapy for conditions, including cancer, immunological disorders, atherosclerosis, phototherapy, etc. PMINs are a potential drug delivery system that combines the advantages of platelet membranes with nanoparticles. The capacity to create PMMNs with particular therapeutic cargo and surface markers provides new possibilities for targeted medication administration and might completely change the way that medicine is practiced. Despite the need for more studies to optimize the engineering process and evaluate the effectiveness and safety of PMINs in clinical trials, this technology has a lot of potential.

Cell Membrane-Camouflaged Nanoparticles Mediated Nucleic Acids Delivery

Nucleic acids have emerged as promising therapeutic agents for many diseases because of their potential in modulating gene expression. However, the delivery of nucleic acids remains a significant challenge in gene therapy. Although viral vectors have shown high transfection efficiency, concerns regarding teratogenicity or carcinogenicity have been raised. Non-viral vehicles, including cationic polymers, liposomes, and inorganic materials possess advantages in terms of safety, ease of preparation, and low cost. Nevertheless, they also face limitations related to immunogenicity, quick clearance in vivo, and lack of targeting specificity. On the other hand, bioinspired strategies have shown increasing potential in the field of drug delivery, yet there is a lack of comprehensive reviews summarizing the rapid development of bioinspired nanoparticles based on the cell membrane camouflage to construct the nucleic acids vehicles. Herein, we enumerated the current difficulties in nucleic acid delivery with various non-viral vehicles and provided an overview of bioinspired strategies for nucleic acid delivery.

Multifunctional cell membranes-based nano-carriers for targeted therapies: a review of recent trends and future perspective

Nanotechnology has ignited a transformative revolution in disease detection, prevention, management, and treatment. Central to this paradigm shift is the innovative realm of cell membrane-based nanocarriers, a burgeoning class of biomimetic nanoparticles (NPs) that redefine the boundaries of biomedical applications. These remarkable nanocarriers, designed through a top-down approach, harness the intrinsic properties of cell-derived materials as their fundamental building blocks. Through shrouding themselves in natural cell membranes, these nanocarriers extend their circulation longevity and empower themselves to intricately navigate and modulate the multifaceted microenvironments associated with various diseases. This comprehensive review provides a panoramic view of recent breakthroughs in biomimetic nanomaterials, emphasizing their diverse applications in cancer treatment, cardiovascular therapy, viral infections, COVID-19 management, and autoimmune diseases. In this exposition, we deliver a concise yet illuminating overview of the distinctive properties underpinning biomimetic nanomaterials, elucidating their pivotal role in biomedical innovation. We subsequently delve into the exceptional advantages these nanomaterials offer, shedding light on the unique attributes that position them at the forefront of cutting-edge research. Moreover, we briefly explore the intricate synthesis processes employed in creating these biomimetic nanocarriers, shedding light on the methodologies that drive their development.

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.

Biomimetic platelet-camouflaged drug-loaded polypyrrole for the precise targeted antithrombotic therapy

Lower extremity deep venous thrombosis (LEDVT) affects patient's quality of life for a long time, and even causes pulmonary embolism, which threatens human health. Current anticoagulant drugs in clinical treatment are hampered by the risk of bleeding due to poor targeting and low drug penetration. Here, we used platelet (PLT)-like biological targeting to enhance the delivery and accumulation of nanomedicines in thrombus and reduce the risk of bleeding. Meanwhile, the parallel strategy of "thrombus thermal ablation and anticoagulation" was applied to increase the permeability of drugs in thrombus and achieve the optimal antithrombotic effect. Polypyrrole (PPy) and rivaroxban (Riv, an anticoagulant drug) were co-assembled into platelet membrane-coated nanoparticles (NPs), PLT-PPy/Riv NPs, which actively targeted the thrombotic lesion at multiple targets in the platelet membrane and were thermally and drug-specific thrombolysed by 808 nm laser irradiation. The combination therapy resulted in up to 90% thrombolysis in a femoral vein thrombosis model compared to single phototherapy or drug therapy. The results showed that the nanoformulation provided a new direction for remote precise and controlled sustained thrombolysis, which was in line with the trend of nanomedicine towards clinical translation.

Biomimetic Platelet Nanomotors for Site-Specific Thrombolysis and Ischemic Injury Alleviation

Due to the mortality associated with thrombosis and its high recurrence rate, there is a need to investigate antithrombotic approaches. Noninvasive site-specific thrombolysis is a current approach being used; however, its usage is characterized by the following limitations: low targeting efficiency, poor ability to penetrate clots, rapid half-life, lack of vascular restoration mechanisms, and risk of thrombus recurrence that is comparable to that of traditional pharmacological thrombolysis agents. Therefore, it is vital to develop an alternative technique that can overcome the aforementioned limitations. To this end, a cotton-ball-shaped platelet (PLT)-mimetic self-assembly framework engineered with a phototherapeutic poly(3,4-ethylenedioxythiophene) (PEDOT) platform has been developed. This platform is capable of delivering a synthetic peptide derived from hirudin P6 (P6) to thrombus lesions, forming P6@PEDOT@PLT nanomotors for noninvasive site-specific thrombolysis, effective anticoagulation, and vascular restoration. Regulated by P-selectin mediation, the P6@PEDOT@PLT nanomotors target the thrombus site and subsequently rupture under near-infrared (NIR) irradiation, achieving desirable sequential drug delivery. Furthermore, the movement ability of the P6@PEDOT@PLT nanomotors under NIR irradiation enables effective penetration deep into thrombus lesions, enhancing bioavailability. Biodistribution analyses have shown that the administered P6@PEDOT@PLT nanomotors exhibit extended circulation time and metabolic capabilities. In addition, the photothermal therapy/photoelectric therapy combination can significantly augment the effectiveness (ca. 72%) of thrombolysis. Consequently, the precisely delivered drug and the resultant phototherapeutic-driven heat-shock protein, immunomodulatory, anti-inflammatory, and inhibitory plasminogen activator inhibitor-1 (PAI-1) activities can restore vessels and effectively prevent rethrombosis. The described biomimetic P6@PEDOT@PLT nanomotors represent a promising option for improving the efficacy of antithrombotic therapy in thrombus-related illnesses.

Enhanced Proliferation of Visualizable Mesenchymal Stem Cell-Platelet Hybrid Cell for Versatile Intracerebral Hemorrhage Treatment

The intrinsic features and functions of platelets and mesenchymal stem cells (MSCs) indicate their great potential in the treatment of intracerebral hemorrhage (ICH). However, neither of them can completely overcome ICH because of the stealth process and the complex pathology of ICH. Here, we fabricate hybrid cells for versatile and highly efficient ICH therapy by fusing MSCs with platelets and loading with lysophosphatidic acid-modified PbS quantum dots (LPA-QDs). The obtained LPA-QDs@FCs (FCs = fusion cells) not only inherit the capabilities of both platelets and MSCs but also exhibit clearly enhanced proliferation activated by LPA. After systemic administration, many proliferating LPA-QDs@FCs rapidly accumulate in ICH areas for responding to the vascular damage and inflammation and then efficiently prevent both the primary and secondary injuries of ICH but with no obvious side effects. Moreover, the treatment process can be tracked by near-infrared II fluorescence imaging with highly spatiotemporal resolution, providing a promising solution for ICH therapy.

Self-actuated biomimetic nanocomposites for photothermal therapy and PD-L1 immunosuppression

Biomimetic nanocomposites are widely used in the biomedical field because they can effectively solve the problems existing in the current cancer treatment by realizing multi-mode collaborative treatment. In this study, we designed and synthesized a multifunctional therapeutic platform (PB/PM/HRP/Apt) with unique working mechanism and good tumor treatment effect. Prussian blue nanoparticles (PBs) with good photothermal conversion efficiency were used as nuclei and coated with platelet membrane (PM). The ability of platelets (PLTs) to specifically target cancer cells and inflammatory sites can effectively enhance PB accumulation at tumor sites. The surface of the synthesized nanocomposites was modified with horseradish peroxidase (HRP) to enhance the deep penetration of the nanocomposites in cancer cells. In addition, PD-L1 aptamer and 4T1 cell aptamer AS1411 were modified on the nanocomposite to achieve immunotherapy and enhance targeting. The particle size, UV absorption spectrum and Zeta potential of the biomimetic nanocomposite were determined by transmission electron microscope (TEM), Ultraviolet-visible (UV-Vis) spectrophotometer and nano-particle size meter, and the successful preparation was proved. In addition, the biomimetic nanocomposites were proved to have good photothermal properties by infrared thermography. The cytotoxicity test showed that it had a good killing ability of cancer cells. Finally, thermal imaging, tumor volume detection, immune factor detection and Haematoxilin-Eosin (HE) staining of mice showed that the biomimetic nanocomposites had good anti-tumor effect and could trigger immune response in vivo. Therefore, this biomimetic nanoplatform as a promising therapeutic strategy provides new inspiration for the current diagnosis and treatment of cancer.

Pollen-Inspired Shell-Core Aerosol Particles Capable of Brownian Motion for Pulmonary Vascularization

Nebulization is the most widely used respiratory delivery technique with non-invasive properties. However, nebulized drugs often fail to function due to the excretion and immune clearance of the respiratory system. In this work, inspired by pollen in nature, novel shell-core aerosol particles (APs) capable of Brownian motion are constructed for respiratory delivery. Drugs-loaded poly(lactic-co-glycolic acid) nanoparticles are prepared by emulsification to form the inner core, and the membranes of macrophages are extracted to form the outer shell. The optimized size and the shell-core structure endow APs with Brownian motion and atomization stability, thus enabling the APs to reach the bronchi and alveoli deeply for effective deposition. Camouflaging the macrophage membranes equips the APs with immune evasion. In vitro experiments prove that deferoxamine (DFO)-loaded APs (DFO@APs) can promote the angiogenesis of human umbilical vein endothelial cells. A hyperoxia-induced bronchopulmonary dysplasia (BPD) model is constructed to validate the efficiency of DFO@APs. In BPD mice, DFO@APs can release DFO in the alveolar interstitium, thus promoting the reconstruction of microvasculature, ultimately inducing lung development for treating BPD. In conclusion, this study develops "pollen"-inspired shell-core aerosol particles capable of Brownian motion, which provides a novel idea and theoretical basis for respiratory administration.

Biomimetic cell membrane-coated poly(lactic-co-glycolic acid) nanoparticles for biomedical applications

Poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) are commonly used for drug delivery because of their favored biocompatibility and suitability for sustained and controlled drug release. To prolong NP circulation time, enable target-specific drug delivery and overcome physiological barriers, NPs camouflaged in cell membranes have been developed and evaluated to improve drug delivery. Here, we discuss recent advances in cell membrane-coated PLGA NPs, their preparation methods, and their application to cancer therapy, management of inflammation, treatment of cardiovascular disease and control of infection. We address the current challenges and highlight future research directions needed for effective use of cell membrane-camouflaged NPs.

Sequential targeting biomimetic nano platform for enhanced mild photothermal therapy and chemotherapy of tumor

Tumor targeting drug delivery is of significant importance for the treatment of triple negative breast cancer (TNBC) considering the presence of appreciable amount of tumor matrix and the absence of effective targets on the tumor cells. Hence in this study, a new therapeutic multifunctional nanoplatform with improved TNBC targeting ability and efficacy was constructed and used for therapy of TNBC. Specifically, curcumin loaded mesoporous polydopamine (mPDA/Cur) nanoparticles were synthesized. Thereafter, manganese dioxide (MnO₂) and a hybrid of cancer-associated fibroblasts (CAFs) membranes as well as cancer cell membranes were sequentially coated on the surface of mPDA/Cur to obtain mPDA/Cur@M/CM. It was found that two distinct kinds of cell membranes were able to endow the nano platform with homologous targeting ability, thereby achieving accurate delivery of drugs. Nanoparticles gathered in the tumor matrix can loosen the tumor matrix via the photothermal effect mediated by mPDA to rupture the physical barrier of tumor, which is conducive to the penetration and targeting of drugs to tumor cells in the deep tissues. Moreover, the existence of curcumin, MnO₂ and mPDA was able to promote the apoptosis of cancer cells by promoting increased cytotoxicity, enhanced Fenton-like reaction, and thermal damage, respectively. Overall, both in vitro and in vivo results showed that the designed biomimetic nanoplatform could significantly inhibit the tumor growth and thus provide an efficient novel therapeutic strategy for TNBC.

Glycoprotein Ib-regulated micro platelet ghost for biosafe distribution and photothermal oncotherapy

Despite the tremendous theranostics potential of nano-scale drug delivery system (NDDS) in oncology field, their tumor-targeting efficiency and safety remain major challenges due to their proneness of off-target accumulation through widespread vascular endothelial gaps (up to 1 μm). To address this problem, in this research, micro-sized cellular platelet "ghosts" (PGs, 1.32 μm, platelet without inner granules and coagulation) were employed as carriers to ship hollow gold nanoparticles (HGNs, 58.7 nm), forming a hierarchical biosafe system (PG@HGNs) to reduce normal tissue interception and enhance tumor targeting delivery of HGNs for improved photothermal therapy. PGs were prepared by an optimized "swelling-extrusion-elution" method, HGNs were loaded in PGs (PG@HGNs) through a "hypotonic dialysis" method and the safety and biodistribution of the system was evaluated in vitro and in vivo. In in vitro condition that stimulated the tumoral vessel acidic microenvironment (pH = 6.5), PG@HGNs were demonstrated with enhanced membrane fluidity through down-regulation of the glycoprotein Ib expressed on the PGs. This change induced a burst release of nano-sized HGNs which were capable to traverse vascular endothelium layer on a tumor-endothelial cell transwell model, whilst the micro-sized PG carriers were intercepted. In comparison to nano-sized platelet membrane-coated carriers (PM@HGNs), PG@HGNs showed enhanced internalization and cytotoxicity to 4T1 cells. In animal models, PG@HGNs remarkably prolonged circulation most likely due to the presence of "self-recognition" receptor-CD47 of PGs, and effectively reduced normal tissue interception via the micro-scale size effect. These both contributed to the significantly improved tumor targeting efficiency of HGNs. PG@HGNs generated the greater antitumor photothermal efficacy alongside safety in the animals compared to PM@HGNs. Collectively, this study demonstrated the potential of the micro-scale PGs equipped with adjusted membrane GP Ib as biosafe vehicles for HGNs or possibly other nanodrugs. THE STATEMENT OF SIGNIFICANCE: Despite the tremendous theranostics potentials, the safety and tumor-targeting efficiency of nano-scale drug delivery systems (NDDS) are compromised by their undesirable accumulation in normal tissues with widespread vascular endothelial gaps, such as many tumor-targeted NDDSs still accumulated much in liver and/or spleen. Herein, we explored a micro-nano biomimetic cascade delivery system to address the above drawbacks. By forming a hierarchical biosafe system, micro-sized platelet "ghost" (PGs, 1.32 μm) was employed as tumor-targeted delivery carrier to transport hollow gold nanoparticles (HGNs, 58.7 nm). It was demonstrated that this micro-size system could maintain platelet membrane structure thus prolong in vivo circulation, while avoiding extravasation into normal tissues. PG@HGNs could sensitively respond to the acidic microenvironment near tumor vessel via down-regulation of glycoprotein Ib and rapidly release "nano-bullets"-HGNs to further penetrate into the tumor tissues through EPR effect, thus enhancing photothermal efficacy generated by HGNs under NIR irradiation. Collectively, the micro-scaled PGs could be biosafe vehicles for improved tumor-targeted delivery of HGNs or possibly other nanodrugs.

Cyclo(RGD) peptide-decorated silver nanoparticles with anti-platelet potential for active platelet-rich thrombus targeting

The development of integrated nanomedicine for prevention and early diagnosis of thrombosis is highly significant. Platelet plays a vital role in thrombotic disorders, offering an ideal target for thromboprophylaxis and imaging of thrombi. We herein fabricated cyclo(RGD) peptide-decorated AgNPs (designated cRGD-AgNPs) for active targeting platelet-rich thrombi. In vitro cytotoxicity and hemolysis assays demonstrated that cRGD-AgNPs have acceptable biocompatibility pattern. Both PEG-AgNPs (non-targeted version) and cRGD-AgNPs can inhibit agonist-mediated platelet aggregation, whereas the latter exhibited significant attenuation on platelet activation and adhesion onto collagen and fibrinogen matrix. Furthermore, the superior binding ability of cRGD-AgNPs with platelet-rich thrombus was demonstrated in static/dynamic condition in vitro. In vivo studies revealed that cRGD-AgNPs could actively target thrombi in a mouse model of carotid artery thrombi with favorable safety. Our results here suggest that cRGD-AgNPs with intrinsic anti-platelet potential might be promising nano theranostics for thromboprophylaxis and active thrombus targeting.

Nanomaterials: A Promising Therapeutic Approach for Cardiovascular Diseases

Cardiovascular diseases (CVDs) are a primary cause of death globally. A few classic and hybrid treatments exist to treat CVDs. However, they lack in both safety and effectiveness. Thus, innovative nanomaterials for disease diagnosis and treatment are urgently required. The tiny size of nanomaterials allows them to reach more areas of the heart and arteries, making them ideal for CVDs. Atherosclerosis causes arterial stenosis and reduced blood flow. The most common treatment is medication and surgery to stabilize the disease. Nanotechnologies are crucial in treating vascular disease. Nanomaterials may be able to deliver medications to lesion sites after being infused into the circulation. Newer point-of-care devices have also been considered together with nanomaterials. For example, this study will look at the use of nanomaterials in imaging, diagnosing, and treating CVDs.

Nanobiotechnology approaches for cardiovascular diseases: site-specific targeting of drugs and nanoparticles for atherothrombosis

Atherosclerosis and atherothrombosis, the major contributors to cardiovascular diseases (CVDs), represent the leading cause of death worldwide. Current pharmacological therapies have been associated with side effects or are insufficient at halting atherosclerotic progression effectively. Pioneering work harnessing the passive diffusion or endocytosis properties of nanoparticles and advanced biotechnologies in creating recombinant proteins for site-specific delivery have been utilized to overcome these limitations. Since CVDs are complex diseases, the most challenging aspect of developing site-specific therapies is the identification of an individual and unique antigenic epitope that is only expressed in lesions or diseased areas. This review focuses on the pathological mechanism of atherothrombosis and discusses the unique targets that are important during disease progression. We review recent advances in site-specific therapy using novel targeted drug-delivery and nanoparticle-carrier systems. Furthermore, we explore the limitations and future perspectives of site-specific therapy for CVDs.

Engineered platelets-based drug delivery platform for targeted thrombolysis

Thrombolytic agents have thus far yielded limited therapeutic benefits in the treatment of thrombotic disease due to their short half-life, low targeting ability, and association with serious adverse reactions, such as bleeding complications. Inspired by the natural roles of platelets during thrombus formation, we fabricated a platelet-based delivery system (NO@uPA/PLTs) comprising urokinase (uPA) and arginine (Arg) for targeted thrombolysis and inhibition of re-embolism. The anchoring of uPA to the platelet surface by lipid insertion increased the thrombotic targeting and in vivo circulation duration of uPA without disturbing platelet functions. Nitric oxide (NO) generated by the loaded Arg inhibited platelet aggregation and activation at the damaged blood vessel, thereby inhibiting re-embolism. NO@uPA/PLTs effectively accumulated at the thrombi in pulmonary embolism and carotid artery thrombosis model mice and exerted superior thrombolytic efficacy. In addition, the platelet delivery system showed excellent thrombus recurrence prevention ability in a mouse model of secondary carotid artery injury. The coagulation indicators in vivo showed that the platelet-based uPA and NO co-delivery system possessed a low hemorrhagic risk, providing a promising tool for rapid thrombolysis and efficient inhibition of posttreatment re-embolism.

Thrombus-Targeting Polymeric Nanocarriers and Their Biomedical Applications in Thrombolytic Therapy

Due to the high morbidity and mortality of cardiovascular diseases, there is an urgent need for research on antithrombotic strategies. In view of the short half-life, insufficient drug penetration, poor targeting capabilities, and hemorrhagic side-effects of traditional thrombus treatment methods, the combination of thrombolytic therapy and nanocarriers brought by the development of nanotechnology in recent years may provide effective solutions for these undesirable side-effects caused by insufficient targeting. Polymeric nanocarriers, based on macromolecules and various functional groups, can connect specific targeting molecules together through chemical modification to achieve the protection and targeted delivery of thrombolytic drugs. However, simple chemical molecular modifications may be easily affected by the physiological environment encountered in the circulatory system. Therefore, the modification of nanocarriers with cell membranes can provide camouflage to these platforms and help to extend their circulation time while also imparting them with the biological functions of cell membranes, thus providing them with precise targeting capabilities, among which the most important is the biological modification of platelet membranes. In addition, some nanoparticles with their own therapeutic functions have also been developed, such as polypyrrole, which can exhibit a photothermal effect to induce thrombolysis. Herein, combined with the mechanism of thrombosis and thrombolysis, we outline the recent advances achieved with thrombus-targeting nanocarriers with regard to thrombosis treatment. On this basis, the design considerations, advantages, and challenges of these thrombolytic therapies in clinical transformation are discussed.

Cell-derived extracellular vesicles and membranes for tissue repair

Humans have a limited postinjury regenerative ability. Therefore, cell-derived biomaterials have long been utilized for tissue repair. Cells with multipotent differentiation potential, such as stem cells, have been administered to patients for the treatment of various diseases. Researchers expected that these cells would mediate tissue repair and regeneration through their multipotency. However, increasing evidence has suggested that in most stem cell therapies, the paracrine effect but not cell differentiation or regeneration is the major driving force of tissue repair. Additionally, ethical and safety problems have limited the application of stem cell therapies. Therefore, nonliving cell-derived techniques such as extracellular vesicle (EV) therapy and cell membrane-based therapy to fulfil the unmet demand for tissue repair are important. Nonliving cell-derived biomaterials are safer and more controllable, and their efficacy is easier to enhance through bioengineering approaches. Here, we described the development and evolution from cell therapy to EV therapy and cell membrane-based therapy for tissue repair. Furthermore, the latest advances in nonliving cell-derived therapies empowered by advanced engineering techniques are emphatically reviewed, and their potential and challenges in the future are discussed.

Thrombolytic Agents: Nanocarriers in Targeted Release

A thrombus, known as a blood clot, may form within the vascular system of the body and impede blood flow. Thrombosis is the most common underlying pathology of cardiovascular diseases, contributing to high morbidity and mortality. However, the main thrombolytic drugs (urokinase, streptokinase, etc.) have shortcomings, including a short half-life, serious side effects and a lack of targeting, that limit their clinical application. The use of nano-drug delivery systems is expected to address these problems and a variety of approaches, including biological and physical responsive systems, have been explored. In this report, recent advances in the development of targeted nano-drug delivery systems are thoroughly reviewed.

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

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

Hybrid Membrane-Coated Biomimetic Nanoparticles (HM@BNPs): A Multifunctional Nanomaterial for Biomedical Applications

The application of nanoparticles in the diagnosis and treatment of diseases has undergone different developmental stages, but phagocytosis and nonspecific distribution have been the main factors restricting the transformation of nanobased drugs into clinical practice. In the past decade, the design of membrane-coated nanoparticles has gained increasing attention. It is hoped that the combination of the cell membrane's natural biological properties and the functional integration of synthetic nanoparticle systems can compensate for the shortage of traditional nanoparticles. The membrane coating gives the nanoparticles unique biological functions such as immune evasion and targeting capability. However, when the encapsulation of monotypic membranes does not meet the diverse demands of biomedicine, the combination of different cell membranes may offer more possibilities. In this review, the composition, preparation, and advantages of biomimetic nanoparticles coated with hybrid cell membranes are summarized, and the applications of hybrid membrane-coated biomimetic nanoparticles (HM@BNPs) in drug delivery, phototherapy, liquid biopsy, tumor vaccines, immune therapy, and detoxification are reviewed. Finally, the current challenges and opportunities with regard to HM@BNPs are discussed.

Recent Advances of Cell Membrane Coated Nanoparticles in Treating Cardiovascular Disorders

Cardiovascular diseases (CVDs) are the leading cause of death worldwide, causing approximately 17.9 million deaths annually, an estimated 31% of all deaths, according to the WHO. CVDs are essentially rooted in atherosclerosis and are clinically classified into coronary heart disease, stroke and peripheral vascular disorders. Current clinical interventions include early diagnosis, the insertion of stents, and long-term preventive therapy. However, clinical diagnostic and therapeutic tools are subject to a number of limitations including, but not limited to, potential toxicity induced by contrast agents and unexpected bleeding caused by anti-platelet drugs. Nanomedicine has achieved great advancements in biomedical area. Among them, cell membrane coated nanoparticles, denoted as CMCNPs, have acquired enormous expectations due to their biomimetic properties. Such membrane coating technology not only helps avoid immune clearance, but also endows nanoparticles with diverse cellular and functional mimicry. In this review, we will describe the superiorities of CMCNPs in treating cardiovascular diseases and their potentials in optimizing current clinical managements.

Erythrocyte membrane bioengineered nanoprobes via indocyanine green-directed assembly for single NIR laser-induced efficient photodynamic/photothermal theranostics

Traditional combinational photodynamic therapy (PDT) and photothermal therapy (PTT) were limited in clinical therapy of cancer due to exceptionally low drug payload and activation by light with separate wavelengths. We have accidentally discovered that zinc phthalocyanine (ZNPC, a typical hydrophobic photosensitizer) and indocyanine green (ICG, a clinically approved fluorescence probe) could be co-assembled into carrier-free nanodrugs (almost 100 wt%) for single NIR laser-induced efficient PDT/PTT. Interestingly, ICG could act as "transformers" for modulating the geometric shape of ZNPC/ICG co-assembling structures from needle-like/spindle-like structure via cubic structure finally to spherical structure. Unfortunately, the nanodrugs suffered from rapid immune clearance. The ZNPC-ICG nanoprobes were further embedded into the erythrocyte membrane (RBC)-camouflaged framework. The designed ZNPC-ICG@RBC could be efficiently accumulated within the tumor sites (continue for ~60 h) and rapidly internalized into cancer cells upon laser irradiation rather than macrophage RAW264.7 cells. Compared with the free ZnPC or ICG, the biomimetic ZNPC-ICG@RBC nanoprobes exhibited amplified therapeutic effects by simultaneously producing ROS and hyperthermia, thereby synergistically improving antitumor efficiency and eliminating the tumors without any regrowth under the guidance of fluorescence imaging. The co-delivery of ZnPC and ICG via a biomimetic carrier-free system might be a promising strategy for bimodal phototherapy of cancer.