Cell-mediated delivery of nanoparticles: taking advantage of circulatory cells to target nanoparticles

Bioengineered Abiotic Nanomaterials Through Cell Membrane-Camouflaging: Advancements and Challenges in Lung Cancer

Lung cancer remains a major global health concern with high mortality rates and poor prognosis. Bridging the gap between the chemical and cellular understanding of cell-decorated biomimetic nanocomposites and their clinical translation is crucial for developing effective therapies. Nanocomposites show promise in targeted drug delivery and diagnostics, but their clinical application is hindered by biocompatibility and clearance issues. To overcome these challenges, biomimetic approaches utilizing cell membrane-coated nanomaterials emerge. By camouflaging nanomaterials with cell membranes, the biointerfaces are enhanced, and the inherent properties of the donor cell membranes are acquired. This review provides an overview of recent advancements on cell membrane-coated nanocomposites for lung cancer diagnosis and treatment. It discusses fabrication techniques, biomedical applications, challenges, and future prospects. The incorporation of cell membranes into nanocomposites holds potential for improved lung cancer therapy, but further development and refinement are needed for precise tumor targeting. Addressing the identified challenges will pave the way for clinical translation of these biomimetic nanoplatforms and advance lung cancer diagnosis and treatment.

New avenues for cancer immunotherapy: Cell-mediated drug delivery systems

Cancer research has become increasingly complex over the past few decades as knowledge of the heterogeneity of cancer cells, their proliferative ability, and their tumor microenvironments has become available. Although conventional therapies remain the most compelling option for cancer treatment to date, immunotherapy is a promising way to harness natural immune defenses to target and kill cancer cells. Cell-mediated drug delivery systems (CDDSs) have been an active line of research for enhancing the therapeutic efficacy and specificity of cancer immunotherapy. These systems can be tailored to different types of immune cells, allowing immune evasion and accumulation in the tumor microenvironment. By enabling the targeted delivery of therapeutic agents such as immune stimulants, cytokines, antibodies, and antigens, CDDSs have improved the survival of some patients with cancer. This review summarizes the research status of CDDSs, with a focus on their underlying mechanisms of action, biology, and clinical applications. We also discuss opportunities and challenges for implementation of CDDSs into mainstream cancer immunotherapy.

Harnessing cells to improve transport of nanomedicines

Efficient tumour treatment is hampered by the poor selectivity of anticancer drugs, resulting in scarce tumour accumulation and undesired off-target effects. Nano-sized drug-delivery systems in the form of nanoparticles (NPs) have been proposed to improve drug distribution to solid tumours, by virtue of their ability of passive and active tumour targeting. Despite these advantages, literature studies indicated that less than 1% of the administered NPs can successfully reach the tumour mass, highlighting the necessity for more efficient drug transporters in cancer treatment. Living cells, such as blood cells, circulating immune cells, platelets, and stem cells, are often found as an infiltrating component in most solid tumours, because of their ability to naturally circumvent immune recognition, bypass biological barriers, and reach inaccessible tissues through innate tropism and active motility. Therefore, the tumour-homing ability of these cells can be harnessed to design living cell carriers able to improve the transport of drugs and NPs to tumours. Albeit promising, this approach is still in its beginnings and suffers from difficult scalability, high cost, and poor reproducibility. In this review, we present an overview of the most common cell transporters of drugs and NPs, and we discuss how different cell types interact with biological barriers to deliver cargoes of various natures to tumours. Finally, we analyse the different techniques used to load drugs or NPs in living cells and discuss their advantages and disadvantages.

Rapamycin and Hyperoside-Co-loaded Macrophage Delivery System Enhanced Pulmonary Fibrosis Therapy by Autophagy Upregulation and Epithelial-to-Mesenchymal Transition Inhibition

Pulmonary fibrosis is a lethal interstitial lung disease, for which current treatments are inadequate in halting its progression. A significant factor contributing to the development of fibrosis is insufficient autophagy, which leads to increased fibroblast proliferation and collagen deposition. However, treatments aimed at upregulating autophagy often cause further lung pathology due to the disruption of epithelial cell balance. In response, we have developed a novel macrophage delivery system loaded with an epithelial-to-mesenchymal transition inhibitor, hyperoside (HYP), and an autophagy inducer, rapamycin (RAP). This system targets the fibrotic areas of the lung through chemotaxis, releases liposomes via macrophage extracellular traps, and effectively inhibits fibroblast proliferation while restoring the alveolar structure through the combined effects of RAP and HYP, ultimately reducing lung pathology without causing systemic toxicity. Our findings not only highlight a promising method to enhance autophagy-based treatments for pulmonary fibrosis but also demonstrate the potential of macrophages as effective nanocarriers for drug delivery.

Transvascular transport of nanocarriers for tumor delivery

Nanocarriers (NCs) play a crucial role in delivering theranostic agents to tumors, making them a pivotal focus of research. However, the persistently low delivery efficiency of engineered NCs has been a significant challenge in the advancement of nanomedicine, stirring considerable debate. Transvascular transport is a critical pathway for NC delivery from vessels to tumors, yet a comprehensive understanding of the interactions between NCs and vascular systems remains elusive. In recent years, considerable efforts have been invested in elucidating the transvascular transport mechanisms of NCs, leading to promising advancements in tumor delivery and theranostics. In this context, we highlight various delivery mechanisms, including the enhanced permeability and retention effect, cooperative immune-driven effect, active transcytosis, and cell/bacteria-mediated delivery. Furthermore, we explore corresponding strategies aimed at enhancing transvascular transport of NCs for efficient tumor delivery. These approaches offer intriguing solutions spanning physicochemical, biological, and pharmacological domains to improve delivery and therapeutic outcomes. Additionally, we propose a forward-looking delivery framework that relies on advanced tumor/vessel models, high-throughput NC libraries, nano-bio interaction datasets, and artificial intelligence, which aims to guide the design of next-generation carriers and implementation strategies for optimized delivery.

Potential applications of macrophages in cancer immunotherapy

Immunotherapy has improved cancer treatment based on investigations of tumor immune escape. Manipulation of the immune system stimulates antitumor immune responses and blocks tumor immune escape routes. Genetically adoptive cell therapy, such as T cells, has yielded promising results for hematologic malignancies, but their application to solid tumors has been challenging. Macrophages have a wide broad of capabilities in regulating immune responses, homeostasis, and tissue development, as well as the ability to phagocyte, present antigens, and infiltrate the tumor microenvironment (TME). Given the importance of macrophages in cancer development, they could serve as novel tool for tumor treatment. Therefore, macrophages are used in different formats for direct and indirect targeting of tumor cells. This review summarized the available data on the various applications of macrophages in cancer immunotherapy.

Systemically targeting monocytic myloid-derrived suppressor cells using dendrimers and their cell-level biodistribution kinetics

The focus of nanoparticles in vivo trafficking has been mostly on their tissue-level biodistribution and clearance. Recent progress in the nanomedicine field suggests that the targeting of nanoparticles to immune cells can be used to modulate the immune response and enhance therapeutic delivery to the diseased tissue. In the presence of tumor lesions, monocytic-myeloid-derived suppressor cells (M-MDSCs) expand significantly in the bone marrow, egress into peripheral blood, and traffic to the solid tumor, where they help maintain an immuno-suppressive tumor microenvironment. In this study, we investigated the interaction between PAMAM dendrimers and M-MDSCs in two murine models of glioblastoma, by examining the cell-level biodistribution kinetics of the systemically injected dendrimers. We found that M-MDSCs in the tumor and lymphoid organs can efficiently endocytose hydroxyl dendrimers. Interestingly, the trafficking of M-MDSCs from the bone marrow to the tumor contributed to the deposition of hydroxyl dendrimers in the tumor. M-MDSCs showed different capacities of endocytosing dendrimers of different functionalities in vivo. This differential uptake was mediated by the unique serum proteins associated with each dendrimer surface functionality. The results of this study set up the framework for developing dendrimer-based immunotherapy to target M-MDSCs for cancer treatment.

Engineering macrophages and their derivatives: A new hope for antitumor therapy

Macrophages are central to the immune system and are found in nearly all tissues. Recently, the development of therapies based on macrophages has attracted significant interest. These therapies utilize macrophages' key roles in immunity, their ability to navigate biological barriers, and their tendency to accumulate in tumors. This review explores the advancement of macrophage-based treatments. We discuss the bioengineering of macrophages for improved anti-tumor effects, the use of CAR macrophage therapy for targeting cancer cells, and macrophages as vehicles for therapeutic delivery. Additionally, we examine engineered macrophage products, like extracellular vesicles and membrane-coated nanoparticles, for their potential in precise and less toxic tumor therapy. Challenges in moving these therapies from research to clinical practice are also highlighted. The aim is to succinctly summarize the current status, challenges, and future directions of engineered macrophages in cancer therapy.

Macrophage based drug delivery: Key challenges and strategies

As a natural immune cell and antigen presenting cell, macrophages have been studied and engineered to treat human diseases. Macrophages are well-suited for use as drug carriers because of their biological characteristics, such as excellent biocompatibility, long circulation, intrinsic inflammatory homing and phagocytosis. Meanwhile, macrophages' uniquely high plasticity and easy re-education polarization facilitates their use as part of efficacious therapeutics for the treatment of inflammatory diseases or tumors. Although recent studies have demonstrated promising advances in macrophage-based drug delivery, several challenges currently hinder further improvement of therapeutic effect and clinical application. This article focuses on the main challenges of utilizing macrophage-based drug delivery, from the selection of macrophage sources, drug loading, and maintenance of macrophage phenotypes, to drug migration and release at target sites. In addition, corresponding strategies and insights related to these challenges are described. Finally, we also provide perspective on shortcomings on the road to clinical translation and production.

Bio-inspired drug delivery systems: A new attempt from bioinspiration to biomedical applications

Natural organisms have evolved sophisticated and multiscale hierarchical structures over time to enable survival. Currently, bionic design is revolutionizing drug delivery systems (DDS), drawing inspiration from the structure and properties of natural organisms that offer new possibilities to overcome the challenges of traditional drug delivery systems. Bionic drug delivery has contributed to a significant improvement in therapeutic outcomes, providing personalized regimens for patients with various diseases and enhancing both their quality of life and drug efficacy. Therefore, it is important to summarize the progress made so far and to discuss the challenges and opportunities for future development. Herein, we review the recent advances in bio-inspired materials, bio-inspired drug vehicles, and drug-loading platforms of biomimetic structures and properties, emphasizing the importance of adapting the structure and function of organisms to meet the needs of drug delivery systems. Finally, we highlight the delivery strategies of bionics in DDS to provide new perspectives and insights into the research and exploration of bionics in DDS. Hopefully, this review will provide future insights into utilizing biologically active vehicles, bio-structures, and bio-functions, leading to better clinical outcomes.

Dendritic Cell Immune Modulation via Polyphenol Membrane Coatings

Cellular hitchhiking is an emerging strategy for the in vivo control of adoptively transferred immune cells. Hitchhiking approaches are primarily mediated by adhesion of nano and microparticles to the cell membrane, which conveys an ability to modulate transferred cells via local drug delivery. Although T cell therapies employing this strategy have progressed into the clinic, phagocytic cells including dendritic cells (DCs) are much more challenging to engineer. DC vaccines hold great potential for a spectrum of diseases, and the combination drug delivery is an attractive strategy to manipulate their function and overcome in vivo plasticity. However, DCs are not compatible with current hitchhiking approaches due to their broad phagocytic capacity. In this work, we developed and validated META (membrane engineering using tannic acid) to enable DC cellular hitchhiking for the first time. META employs the polyphenol tannic acid (TA) to facilitate supramolecular assembly of protein drug cargoes on the cell membrane, enabling the creation of cell surface-bound formulations for local drug delivery to carrier DCs. We optimized META formulations to incorporate and release protein cargoes with varying physical properties alone and in combination and to preserve DC viability and critical functions such as migration. We further show that META loaded with either a pro- or anti-inflammatory cargo can influence the carrier cell phenotype, thus demonstrating the flexibility of the approach for applications from cancer to autoimmune disease. Overall, this approach illustrates a new platform for the local control of phagocytic immune cells as a next step to advance DC therapies in the clinic.

Engineering unactivated platelets for targeted drug delivery

As a vital component of blood, platelets play crucial roles in hemostasis and maintaining vascular integrity, and actively participate in inflammation and immune regulation. The unique biological properties of natural platelets have enabled their utilization as drug delivery vehicles. The advancement and integration of various techniques, including biological, chemical, and physicochemical methods, have enabled the preparation of engineered platelets. Platelets can serve as drug delivery platforms combined with immunotherapy and chemokine therapy to enhance their therapeutic impact. This review focuses on the recent advancements in the application of unactivated platelets for drug delivery. The construction strategies of engineered platelets are comprehensively summarized, encompassing internal loading, surface modification, and genetic engineering techniques. Engineered platelets hold vast potential for treating cardiovascular diseases, cancers, and infectious diseases. Furthermore, the challenges and potential considerations in creating engineered platelets with natural activity are discussed.

Macrophages as carriers of boron carbide nanoparticles dedicated to boron neutron capture therapy

BACKGROUND

The use of cells as carriers for the delivery of nanoparticles is a promising approach in anticancer therapy, mainly due to their natural properties, such as biocompatibility and non-immunogenicity. Cellular carriers prevent the rapid degradation of nanoparticles, improve their distribution, reduce cytotoxicity and ensure selective delivery to the tumor microenvironment. Therefore, we propose the use of phagocytic cells as boron carbide nanoparticle carriers for boron delivery to the tumor microenvironment in boron neutron capture therapy.

RESULTS

Macrophages originating from cell lines and bone marrow showed a greater ability to interact with boron carbide (B4C) than dendritic cells, especially the preparation containing larger nanoparticles (B4C 2). Consequently, B4C 2 caused greater toxicity and induced the secretion of pro-inflammatory cytokines by these cells. However, migration assays demonstrated that macrophages loaded with B4C 1 migrated more efficiently than with B4C 2. Therefore, smaller nanoparticles (B4C 1) with lower toxicity but similar ability to activate macrophages proved to be more attractive.

CONCLUSIONS

Macrophages could be promising cellular carriers for boron carbide nanoparticle delivery, especially B4C 1 to the tumor microenvironment and thus prospective use in boron neutron capture therapy.

Neutrophil hitchhiking: Riding the drug delivery wave to treat diseases

Neutrophils are a crucial component of the innate immune system and play a pivotal role in various physiological processes. From a physical perspective, hitchhiking is considered a phenomenon of efficient transportation. The combination of neutrophils and hitchhikers has given rise to effective delivery systems both in vivo and in vitro, thus neutrophils hitchhiking become a novel approach to disease treatment. This article provides an overview of the innovative and feasible application of neutrophils as drug carriers. It explores the mechanisms underlying neutrophil function, elucidates the mechanism of drug delivery mediated by neutrophil-hitchhiking, and discusses the potential applications of this strategy in the treatment of cancer, immune diseases, inflammatory diseases, and other medical conditions.

Functionalization and magnetonavigation of T-lymphocytes functionalized via nanocomposite capsules targeting with electromagnetic tweezers

Modification of T-lymphocytes, which are capable of paracellular transmigration is a promising trend in modern personalized medicine. However, the delivery of required concentrations of functionalized T-cells to the target tissues remains a problem. We describe a novel method to functionalize T-cells with magnetic nanocapsules and target them with electromagnetic tweezers. T-cells were modified with the following magnetic capsules: Parg/DEX (150 nm), BSA/TA (300 nm), and BSA/TA (500 nm). T-cells were magnetonavigated in a phantom blood vessel capillary in cultural medium and in whole blood. The permeability of tumor tissues to captured T-cells was analyzed by magnetic delivery of modified T-cells to spheroids formed from 4T1 breast cancer cells. The dynamics of T-cell motion under a magnetic field gradient in model environments were analyzed by particle image velocimetry. The magnetic properties of the nanocomposite capsules and magnetic T-cells were measured. The obtained results are promising for biomedical applications in cancer immunotherapy.

Immune cells: potential carriers or agents for drug delivery to the central nervous system

Drug delivery systems (DDS) have recently emerged as a promising approach for the unique advantages of drug protection and targeted delivery. However, the access of nanoparticles/drugs to the central nervous system (CNS) remains a challenge mainly due to the obstruction from brain barriers. Immune cells infiltrating the CNS in the pathological state have inspired the development of strategies for CNS foundation drug delivery. Herein, we outline the three major brain barriers in the CNS and the mechanisms by which immune cells migrate across the blood-brain barrier. We subsequently review biomimetic strategies utilizing immune cell-based nanoparticles for the delivery of nanoparticles/drugs to the CNS, as well as recent progress in rationally engineering immune cell-based DDS for CNS diseases. Finally, we discuss the challenges and opportunities of immune cell-based DDS in CNS diseases to promote their clinical development.

In situ cellular hitchhiking of nanoparticles for drug delivery

Since the inception of the concept of "magic bullet", nanoparticles have evolved to be one of the most effective carriers in drug delivery. Nanoparticles improve the therapeutic efficacy of drugs offering benefits to treating various diseases. Unlike free drugs which freely diffuse and distribute through the body, nanoparticles protect the body from the drug by reducing non-specific interactions while also improving the drug's pharmacokinetics. Despite acquiring some FDA approvals, further clinical application of nanoparticles is majorly hindered by its limited ability to overcome biological barriers resulting in uncontrolled biodistribution and high clearance. The use of cell-inspired systems has emerged as a promising approach to overcome this challenge as cells are biocompatible and have improved access to tissues and organs. One of such is the hitchhiking of nanoparticles to circulating cells such that they are recognized as 'self' components evading clearance and resulting in site-specific drug delivery. In this review, we discuss the concept of nanoparticle cellular hitchhiking, highlighting its advantages, the principles governing the process and the challenges currently limiting its clinical translation. We also discuss in situ hitchhiking as a tool for overcoming these challenges and the considerations to be taken to guide research efforts in advancing this promising technology.

Tumor-tropic Trojan horses: Using mesenchymal stem cells as cellular nanotheranostics

Various classes of nanotheranostics have been developed for enhanced tumor imaging and therapy. However, key limitations for a successful use of nanotheranostics include their targeting specificity with limited off-site tissue accumulation as well as their distribution and prolonged retention throughout the entire tumor. Due to their inherent tumor-tropic properties, the use of mesenchymal stem cells (MSCs) as a "Trojan horse" has recently been proposed to deliver nanotheranostics more effectively. This review discusses the current status of "cellular nanotheranostics" for combined (multimodal) imaging and therapy in preclinical cancer models. Emphasis is placed on the limited knowledge of the signaling pathways and molecular mechanisms of MSC tumor-tropism, and how such information may be exploited to engineer MSCs in order to further improve tumor homing and nanotheranostic delivery using image-guided procedures.

Yeast glucan particles: An express train for oral targeted drug delivery systems

As an emerging drug delivery vehicle, yeast glucan particles (YGPs) derived from yeast cells could be specifically taken up by macrophages. Therefore, these vehicles could rely on the recruitment of macrophages at the site of inflammation and tumors to enable targeted imaging and drug delivery. This review summarizes recent advances in the application of YGPs in oral targeted delivery systems, covering the basic structure of yeast cells, methods for pre-preparation, drug encapsulation and characterization. The mechanism and validation of the target recognition interaction of YGPs with macrophages are highlighted, and some inspiring cases are presented to show that yeast cells have promising applications. The future chances and difficulties that YGPs will confront are also emphasized throughout this essay. YGPs are not only the "armor" but also the "compass" of drugs in the process of targeted drug transport. This system is expected to provide a new idea about the oral targeted delivery of anti-inflammatory and anti-tumor drugs, and furthermore offer an effective delivery strategy for targeted therapy of other macrophage-related diseases.

Evasion of opsonization of macromolecules using novel surface-modification and biological-camouflage-mediated techniques for next-generation drug delivery

Opsonization plays a pivotal role in hindering controlled drug release from nanoformulations due to macrophage-mediated nanoparticle destruction. While first and second-generation delivery systems, such as lipoplexes (50-150 nm) and quantum dots, hold immense potential in revolutionizing disease treatment through spatiotemporal controlled drug delivery, their therapeutic efficacy is restricted by the selective labeling of nanoparticles for uptake by reticuloendothelial system and mononuclear phagocyte system via various molecular forces, such as electrostatic, hydrophobic, and van der Waals bonds. This review article presents novel insights into surface-modification techniques utilizing macromolecule-mediated approaches, including PEGylation, di-block copolymerization, and multi-block polymerization. These techniques induce stealth properties by generating steric forces to repel micromolecular-opsonins, such as fibrinogen, thereby mitigating opsonization effects. Moreover, advanced biological methods, like cellular hitchhiking and dysopsonic protein adsorption, are highlighted for their potential to induce biological camouflage by adsorbing onto the nanoparticulate surface, leading to immune escape. These significant findings pave the way for the development of long-circulating next-generation nanoplatforms capable of delivering superior therapy to patients. Future integration of artificial intelligence-based algorithms, integrated with nanoparticle properties such as shape, size, and surface chemistry, can aid in elucidating nanoparticulate-surface morphology and predicting interactions with the immune system, providing valuable insights into the probable path of opsonization.

Biomimetic nanomedicines for precise atherosclerosis theranostics

Atherosclerosis (AS) is a leading cause of the life-threatening cardiovascular disease (CVD), creating an urgent need for efficient, biocompatible therapeutics for diagnosis and treatment. Biomimetic nanomedicines (bNMs) are moving closer to fulfilling this need, pushing back the frontier of nano-based drug delivery systems design. This review seeks to outline how these nanomedicines (NMs) might work to diagnose and treat atherosclerosis, to trace the trajectory of their development to date and in the coming years, and to provide a foundation for further discussion about atherosclerotic theranostics.

DNase based therapeutic approaches for the treatment of NETosis related inflammatory diseases

Neutrophils are the primary host innate immune cells defending against pathogens. One proposed mechanism by which neutrophils limit pathogen transmission is NETosis, which includes releasing the nuclear content into the cytosol by forming pores in the plasma membrane. The extrusion of cellular deoxyribonucleic acid (DNA) results in neutrophil extracellular traps (NETs) composed of nuclear DNA associated with histones and granule proteins. NETosis is driven by the enzyme PAD-4 (Peptidylarginine deiminase-4), which converts arginine into citrulline, leading to decondensation of chromatin, separation of DNA, and eventual extrusion. DNase is responsible for the breakdown of NETs. On the one hand, the release of DNase may interfere with the antibacterial effects of NETs; further, DNase may protect tissues from self-destruction caused by the increased release of NET under septic conditions. NETs in physiological quantities are expected to have a role in anti-infectious innate immune responses. In contrast, abnormally high concentrations of NETs in the body that are not adequately cleared by DNases can damage tissues and cause inflammation. Through several novel approaches, it is now possible to avoid the adverse effects caused by the continued release of NETs into the extracellular environment. In this review we have highlighted the basic mechanisms of NETosis, its significance in the pathogenesis of various inflammatory disorders, and the role of DNase enzyme with a focus on the possible function of nanotechnology in its management.

Advancement in nanotechnology for treatment of rheumatoid arthritis: scope and potential applications

Rheumatoid arthritis is a hyperactive immune disorder that results in severe inflammation in synovial joints, cartilage, and bone deterioration, resulting in immobilization of joints. Traditional approaches for the treatment of rheumatoid arthritis are associated with some limiting factors such as suboptimal patient compliance, inability to control the progression of disorder, and safety concerns. Therefore, innovative drug delivery carriers for efficient therapeutic delivery at inflamed synovial sites with better safety assessment are urgently needed to address these issues. From this perspective, nanotechnology is an outstanding alternative to traditional drug delivery approaches, and it has shown great promise in developing novel carriers to treat rheumatoid arthritis. Considering the current research and future application of nanocarriers, it is believed that nanocarriers can be a crucial element in rheumatoid arthritis treatment. This paper covers all currently available pathophysiological aspects of rheumatoid arthritis and treatment options. Future research for the reduction of synovial inflammation should focus on developing multifunction nanoparticles capable of delivering therapeutic agents with improved safety, efficacy, and cost-effectiveness to be commercialized.

The interplay between PEGylated nanoparticles and blood immune system

During the last two decades, an increasing number of reports have pointed out that the immunogenicity of polyethylene glycol (PEG) may trigger accelerated blood clearance (ABC) and hypersensitivity reaction (HSR) to PEGylated nanoparticles, which could make PEG modification counterproductive. These phenomena would be detrimental to the efficacy of the load and even life-threatening to patients. Consequently, further elucidation of the interplay between PEGylated nanoparticles and the blood immune system will be beneficial to developing and applying related formulations. Many groups have worked to unveil the relevance of structural factors, dosing schedule, and other factors to the ABC phenomenon and hypersensitivity reaction. Interestingly, the results of some reports seem to be difficult to interpret or contradict with other reports. In this review, we summarize the physiological mechanisms of PEG-specific immune response. Moreover, we speculate on the potential relationship between the induction phase and the effectuation phase to explain the divergent results in published reports. In addition, the role of nanoparticle-associated factors is discussed based on the classification of the action phase. This review may help researchers to develop PEGylated nanoparticles to avoid unfavorable immune responses based on the underlying mechanism.

Revolutionizing cancer treatment: The power of cell-based drug delivery systems

Intravenous administration of drugs is a widely used cancer therapy approach. However, the efficacy of these drugs is often hindered by various biological barriers, including circulation, accumulation, and penetration, resulting in poor delivery to solid tumors. Recently, cell-based drug delivery platforms have emerged as promising solutions to overcome these limitations. These platforms offer several advantages, including prolonged circulation time, active targeting, controlled release, and excellent biocompatibility. Cell-based delivery systems encompass cell membrane coating, intracellular loading, and extracellular backpacking. These innovative platforms hold the potential to revolutionize cancer diagnosis, monitoring, and treatment, presenting a plethora of opportunities for the advancement and integration of pharmaceuticals, medicine, and materials science. Nevertheless, several technological, ethical, and financial barriers must be addressed to facilitate the translation of these platforms into clinical practice. In this review, we explore the emerging strategies to overcome these challenges, focusing specifically on the functions and advantages of cell-mediated drug delivery in cancer treatment.

Advanced hitchhiking nanomaterials for biomedical applications

Hitchhiking, a recently developed bio-inspired cargo delivery system, has been harnessed for diverse applications. By leveraging the interactions between nanoparticles and circulatory cells or proteins, hitchhiking enables efficient navigation through the vasculature while evading immune system clearance. Moreover, it allows for targeted delivery of nutrients to tissues, surveillance of the immune system, and pathogen elimination. Various synthetic nanomaterials have been developed to facilitate hitchhiking with circulatory cells or proteins. By combining the advantages of synthetic nanomaterials and circulatory cells or proteins, hitchhiking nanomaterials demonstrate several advantages over conventional vectors, including enhanced circulatory stability and optimized therapeutic efficacy. This review provides an overview of general strategies for hitchhiking, choices of cells and proteins, and recent advances of hitchhiking nanomaterials for biomedical applications.

Nature-inspired nanocarriers for improving drug therapy of atherosclerosis

Atherosclerosis (AS) has emerged as one of the prevalent arterial vascular diseases characterized by plaque and inflammation, primarily causing disability and mortality globally. Drug therapy remains the main treatment for AS. However, a series of obstacles hinder effective drug delivery. Nature, from natural micro-/nano-structural biological particles like natural cells and extracellular vesicles to the distinctions between the normal and pathological microenvironment, offers compelling solutions for efficient drug delivery. Nature-inspired nanocarriers of synthetic stimulus-responsive materials and natural components, such as lipids, proteins and membrane structures, have emerged as promising candidates for fulfilling drug delivery needs. These nanocarriers offer several advantages, including prolonged blood circulation, targeted plaque delivery, targeted specific cells delivery and controlled drug release at the action site. In this review, we discuss the nature-inspired nanocarriers which leverage the natural properties of cells or the microenvironment to improve atherosclerotic drug therapy. Finally, we provide an overview of the challenges and opportunities of applying these innovative nature-inspired nanocarriers.

Macrophages as Promising Carriers for Nanoparticle Delivery in Anticancer Therapy

Macrophages play a critical role in the immune response due to their ability to recognize and remove pathogens, as well as present antigens, which are involved in inflammation, but they are also one of the most abundant immune cell populations present in the tumor microenvironment. In recent years, macrophages have become promising cellular carriers for drug and nanoparticle delivery to the tumor microenvironment, mainly due to their natural properties such as biocompatibility, degradability, lack of immunogenicity, long half-life in circulation, crossing biological barriers, and the possibility of migration and accumulation at a site of inflammation such as a tumor. For the effectiveness of this therapeutic strategy, known as "Trojan horse", it is important that the nanoparticles engulfed by macrophages do not affect their proper functioning. In our review, we discussed how the size, shape, chemical and mechanical properties of nanoparticles influence their internalization by macrophages. In addition, we described the promising research utilizing macrophages, their cell membranes and macrophage-derived exosomes as drug carriers in anticancer therapy. As a prospect of the wider use of this therapeutic strategy, we postulate its future application in boron delivery to the tumor environment in boron neutron capture therapy.

Knowledge Gaps in Generating Cell-Based Drug Delivery Systems and a Possible Meeting with Artificial Intelligence

Cell-based drug delivery systems are new strategies in targeted delivery in which cells or cell-membrane-derived systems are used as carriers and release their cargo in a controlled manner. Recently, great attention has been directed to cells as carrier systems for treating several diseases. There are various challenges in the development of cell-based drug delivery systems. The prediction of the properties of these platforms is a prerequisite step in their development to reduce undesirable effects. Integrating nanotechnology and artificial intelligence leads to more innovative technologies. Artificial intelligence quickly mines data and makes decisions more quickly and accurately. Machine learning as a subset of the broader artificial intelligence has been used in nanomedicine to design safer nanomaterials. Here, how challenges of developing cell-based drug delivery systems can be solved with potential predictive models of artificial intelligence and machine learning is portrayed. The most famous cell-based drug delivery systems and their challenges are described. Last but not least, artificial intelligence and most of its types used in nanomedicine are highlighted. The present Review has shown the challenges of developing cells or their derivatives as carriers and how they can be used with potential predictive models of artificial intelligence and machine learning.

Modulation of engineered nanomaterial interactions with organ barriers for enhanced drug transport

The biomedical use of nanoparticles (NPs) has been the focus of intense research for over a decade. As most NPs are explored as carriers to alter the biodistribution, pharmacokinetics and bioavailability of associated drugs, the delivery of these NPs to the tissues of interest remains an important topic. To date, the majority of NP delivery studies have used tumor models as their tool of interest, and the limitations concerning tumor targeting of systemically administered NPs have been well studied. In recent years, the focus has also shifted to other organs, each presenting their own unique delivery challenges to overcome. In this review, we discuss the recent advances in leveraging NPs to overcome four major biological barriers including the lung mucus, the gastrointestinal mucus, the placental barrier, and the blood-brain barrier. We define the specific properties of these biological barriers, discuss the challenges related to NP transport across them, and provide an overview of recent advances in the field. We discuss the strengths and shortcomings of different strategies to facilitate NP transport across the barriers and highlight some key findings that can stimulate further advances in this field.

Deoxyribonucleic Acid-Based Polyvalent Ligand-Receptor Binding for Engineering the Cell Surface with Nanoparticles

Tethering nanoparticles (NPs) onto the cell surface is critical to cellular hitchhiking applications, such as targeted NP delivery and enhanced cell therapy. While numerous methods have been developed to achieve NP attachment onto the cell membrane, they often face limitations such as the use of complicated cell surface modifications or low-efficiency NP attachment. The purpose of this work was to explore a DNA-based synthetic ligand-receptor pair for NP attachment to the surface of live cells. Polyvalent ligand mimics were used to functionalize NPs, while the cell membrane was functionalized with DNA-based cell receptor mimics. Base pair-directed polyvalent hybridization allowed the NPs to bind to the cells quickly and efficiently. Notably, the process of attaching NPs to cells did not require sophisticated chemical conjugation on the cell membrane or involve any cytotoxic cationic polymers. Therefore, DNA-based polyvalent ligand-receptor binding is promising to various applications ranging from cell surface engineering to NP delivery.

Myeloid cell-mediated drug delivery: from nanomedicine to cell therapy

In the presence of tissue inflammation, injury, or cancer, myeloid cells are recruited to disease regions through a multi-step process involving myelopoiesis, chemotaxis, cell migration, and diapedesis. As an emerging drug delivery approach, cell-mediated drug delivery takes advantage of the cell recruitment process to enhance the active transport of therapeutic cargo to disease regions. In the past few decades, a variety of nano-engineering methods have emerged to enhance interactions of nanoparticles with cells of interest, which can be adapted for cell-mediated drug delivery. Moreover, the drug delivery field can benefit from the recent clinical success of cell-based therapies, which created cell-engineering methods to engineer circulating leukocytes as 'living drug delivery vehicles' to target diseased tissues. In this review, we first provide an overview of myeloid cell recruitment and discuss how various factors within this process may affect cell-mediated delivery. In the second part of this review article, we summarize the status quo of nano-engineering and cell-engineering approaches and discuss how these engineering approaches can be adapted for cell-mediated delivery. Finally, we discuss future directions of this field, pointing out key challenges in the clinical translation of cell-mediated drug delivery.

Versatile biomimetic nanomedicine for treating cancer and inflammation disease

Nanosized drug delivery systems (NDDSs) have emerged as a powerful tool to optimize drug delivery in complex diseases, including cancer and inflammation. However, the therapeutic effect of NDDSs is still far from satisfactory due to their poor circulation time, low delivery efficiency, and innate toxicity. Fortunately, biomimetic approaches offer new opportunities to develop nanomedicine, which is derived from a variety of native biomolecules including cells, exosomes, bacteria, and so on. Since inheriting the superior biocompatibility and versatile functions of natural materials, biomimetic nanomedicine can mimic biological processes, prolong blood circulation, and lower immunogenicity, serving as a desired platform for precise drug delivery for treating cancer and inflammatory disease. In this review, we outline recent advances in biomimetic NDDSs, which consist of two concepts: biomimetic exterior camouflage and bioidentical molecule construction. We summarize engineering strategies that further functionalized current biomimetic NDDSs. A series of functional biomimetic NDDSs created by our group are introduced. We conclude with an outlook on remaining challenges and possible directions for biomimetic NDDSs. We hope that better technologies can be inspired and invented to advance drug delivery systems for cancer and inflammation therapy.

Cannabidiol-loaded biomimetic macrophage membrane vesicles against post-traumatic stress disorder assisted by ultrasound

Post-traumatic stress disorder (PTSD), which normally follows psychological trauma, has been increasingly studied as a brain disease. However, the blood-brain barrier (BBB) prevents conventional drugs for PTSD from entering the brain. Our previous studies proved the effectiveness of cannabidiol (CBD) against PTSD, but low water solubility, low brain targeting efficiency and poor bioavailability restricted its applications. Here, a bionic delivery system, camouflage CBD-loaded macrophage-membrane nanovesicles (CMNVs), was constructed via co-extrusion of CBD with macrophage membranes, which had inflammatory and immune escape properties. In vitro anti-inflammatory, cellular uptake and pharmacokinetic experiments respectively verified the anti-inflammatory, inflammatory targeting and immune escape properties of CMNVs. Brain targeting and excellent anti-PTSD effects of CMNVs had been validated in vivo by imaging and pharmacodynamics studies. In our study, the potential of ultrasound to open BBBs and improve the brain-targeted delivery of CBD was evaluated. In conclusion, this cell membrane bionic delivery system assisted with ultrasound had good therapeutic effect against PTSD mice, which is expected to help convey CBD to inflammatory areas within the brain and alleviate the symptoms of PTSD.

Highly specific neutrophil-mediated delivery of albumin nanoparticles to ectopic lesion for endometriosis therapy

Endometriosis is an estrogen-dependent chronic inflammatory disease. Hormonal and surgical treatments are the most commonly used clinical therapies, but they have many sides effects or are traumatic to the body. Therefore, specific drugs for endometriosis treatment are urgently needed to develop. In this study, we identified two features of endometriosis, namely the continuous recruitment of neutrophils into the ectopic lesions and the higher uptake of glucose by ectopic cells. For the above features, we designed a glucose oxidase-loaded bovine serum albumin nanoparticle (BSA-GOx-NPs) that is inexpensive and facilitates large-scale production. After injection, BSA-GOx-NPs were high specifically delivered to ectopic lesions in a neutrophil-dependent manner. Furthermore, BSA-GOx-NPs deplete glucose and induce apoptosis in the ectopic lesions. Whereupon BSA-GOx-NPs produced excellent anti-endometriosis effects when administrated in both acute and chronic inflammatory phases. These results reveal for the first time that the neutrophil hitchhiking strategy is effective in chronic inflammatory disease and provide a non-hormonal and easy-to-achieve approach for endometriosis treatment.

Nanoparticle Based Cardiac Specific Drug Delivery

Heart failure secondary to myocardial injuries is a leading cause of death worldwide. Recently, a growing number of novel therapies have emerged for injured myocardium repairment. However, delivering therapeutic agents specifically to the injured heart remains a significant challenge. Nanoparticles are the most commonly used vehicles for targeted drug delivery. Various nanoparticles have been synthesized to deliver drugs and other therapeutic molecules to the injured heart via passive or active targeting approaches, and their targeting specificity and therapeutic efficacies have been investigated. Here, we summarized nanoparticle-based, cardiac-specific drug delivery systems, their potency for treating heart diseases, and the mechanisms underlying these cardiac-targeting strategies. We also discussed the clinical studies that have employed nanoparticle-based cardiac-specific drug delivery.

Engineered Macrophages: A Safe-by-Design Approach for the Tumor Targeting Delivery of Sub-5 nm Gold Nanoparticles

Ultrasmall nanoparticles (NPs) are a promising platform for the diagnosis and therapy of cancer, but the particles in sizes as small as several nanometers have an ability to translocate across biological barriers, which may bring unpredictable health risks. Therefore, it is essential to develop workable cell-based tools that can deliver ultrasmall NPs to the tumor in a safer manner. Here, this work uses macrophages as a shuttle to deliver sub-5 nm PEGylated gold (Au) NPs to tumors actively or passively, while reducing the accumulation of Au NPs in the brain. This work demonstrates that sub-5 nm Au NPs can be rapidly exocytosed from live macrophages, reaching 45.6% within 24 h, resulting in a labile Au NP-macrophage system that may release free Au NPs into the blood circulation in vivo. To overcome this shortcoming, two straightforward methods are used to engineer macrophages to obtain "half-dead" and "dead" macrophages. Although the efficiency of engineered macrophages for delivering sub-5 nm Au NPs to tumors is 2.2-3.8% lower than that of free Au NPs via the passive enhanced permeability and retention effect, this safe-by-design approach can dramatically reduce the accumulation of Au NPs in the brain by more than one order of magnitude. These promising approaches offer an opportunity to expand the immune cell- or stem cell-mediated delivery of ultrasmall NPs for the diagnosis and therapy of diseases in a safer way in the future.

Characterization of the interaction of nanobubble ultrasound contrast agents with human blood components

Nanoscale ultrasound contrast agents, or nanobubbles, are being explored in preclinical applications ranging from vascular and cardiac imaging to targeted drug delivery in cancer. These sub-micron particles are approximately 10x smaller than clinically available microbubbles. This allows them to effectively traverse compromised physiological barriers and circulate for extended periods of time. While various aspects of nanobubble behavior have been previously examined, their behavior in human whole blood has not yet been explored. Accordingly, herein we examined, for the first time, the short and long-term effects of blood components on nanobubble acoustic response. We observed differences in the kinetics of backscatter from nanobubble suspensions in whole blood compared to bubbles in phosphate buffered saline (PBS), plasma, or red blood cell solutions (RBCs). Specifically, after introducing nanobubbles to fresh human whole blood, signal enhancement, or the magnitude of nonlinear ultrasound signal, gradually increased by 22.8 ± 13.1% throughout our experiment, with peak intensity reached within 145 s. In contrast, nanobubbles in PBS had a stable signal with negligible change in intensity (−1.7 ± 3.2%) over 8 min. Under the same conditions, microbubbles made with the same lipid formulation showed a −56.8 ± 6.1% decrease in enhancement in whole blood. Subsequent confocal, fluorescent, and scanning electron microscopy analysis revealed attachment of the nanobubbles to the surface of RBCs, suggesting that direct interactions, or hitchhiking, of nanobubbles on RBCs in the presence of plasma may be a possible mechanism for the observed effects. This phenomenon could be key to extending nanobubble circulation time and has broad implications in drug delivery, where RBC interaction with nanoparticles could be exploited to improve delivery efficiency.

•

Show distinct signal enhancement curve of nanobubbles (NB) in human whole blood

•

Compare signal enhancement over time in blood with NBs and microbubbles (MBs)

•

Examine the effect of blood components on NB and MB movement over time

•

Demonstrate, with microscopy, that NBs localize to the RBC surface in whole blood

Cell surface-nanoengineering for cancer targeting immunoregulation and precise immunotherapy

Living cells have become ideal therapeutic agents for cancer treatment owing to their innate activities, such as efficient tumor targeting and delivery, easy engineering, immunomodulatory properties, and fewer adverse effects. However, cell agents are often fragile to rigorous tumor microenvironment (TME) and limited by inadequate therapeutic responses, leading to unwanted treatment efficacy. Cell nanomodification, particularly the cell surface-nanoengineering has emerged as reliable and efficient strategy that not only combines cell activity properties with nanomaterials but also endows them with extra novel functions, enabling to achieve remarkable treatment results. In this review, we systematically introduce two major strategies have been adopted to develop cell surface engineering with nanomaterials, mainly including living cell nano-backpacks and cell membrane-mimicking nanoparticles (NPs). Based on various functional NPs and cell types, we focus on reviewing the cell-surface nanoengineering for targeted drug delivery, immune microenvironment regulation, and precisely antitumor therapy. The advances and challenges of cell surface-nanoengineered antitumor agents for cancer therapy applications are further discussed in future clinical practice. This review provides an overview of the advances in cell surface-engineering for targeting immunoregulation and treatment and could contribute to the future of advanced cell-based antitumor therapeutic applications. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies Nanotechnology Approaches to Biology > Cells at the Nanoscale.

Synergistic chemotherapy and phototherapy based on red blood cell biomimetic nanomaterials

Novel drug delivery systems (DDSs) have become the mainstay of research in targeted cancer therapy. By combining different therapeutic strategies, potential DDSs and synergistic treatment approaches are needed to effectively deal with evolving drug resistance and the adverse effects of cancer. Nowadays, developing and optimizing human cell-based DDSs has become a new research strategy. Among them, red blood cells can be used as DDSs as they significantly enhance the pharmacokinetics of the transported drug cargo. Phototherapy, as a novel adjuvant in cancer treatment, can be divided into photodynamic therapy and photothermal therapy. Phototherapy using erythropoietic nanocarriers to mimic the unique properties of erythrocytes and overcome the limitations of existing DDSs shows excellent prospects in clinical settings. This review provides an overview of the development of photosensitizers and research on bio-nano-delivery systems based on erythrocytes and erythrocyte membranes that are used in achieving synergistic outcomes during phototherapy/chemotherapy.

TRAIL in the Treatment of Cancer: From Soluble Cytokine to Nanosystems

The death ligand tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), a member of the TNF cytokine superfamily, has long been recognized for its potential as a cancer therapeutic due to its low toxicity against normal cells. However, its translation into a therapeutic molecule has not been successful to date, due to its short in vivo half-life associated with insufficient tumor accumulation and resistance of tumor cells to TRAIL-induced killing. Nanotechnology has the capacity to offer solutions to these limitations. This review provides a perspective and a critical assessment of the most promising approaches to realize TRAIL's potential as an anticancer therapeutic, including the development of fusion constructs, encapsulation, nanoparticle functionalization and tumor-targeting, and discusses the current challenges and future perspectives.

Cancer Stem Cells and the Tumor Microenvironment: Targeting the Critical Crosstalk through Nanocarrier Systems

The physiological state of the tumor microenvironment (TME) plays a central role in cancer development due to multiple universal features that transcend heterogeneity and niche specifications, like promoting cancer progression and metastasis. As a result of their preponderant involvement in tumor growth and maintenance through several microsystemic alterations, including hypoxia, oxidative stress, and acidosis, TMEs make for ideal targets in both diagnostic and therapeutic ventures. Correspondingly, methodologies to target TMEs have been investigated this past decade as stratagems of significant potential in the genre of focused cancer treatment. Within targeted oncotherapy, nanomedical derivates-nanocarriers (NCs) especially-have emerged to present notable prospects in enhancing targeting specificity. Yet, one major issue in the application of NCs in microenvironmental directed therapy is that TMEs are too broad a spectrum of targeting possibilities for these carriers to be effectively employed. However, cancer stem cells (CSCs) might portend a solution to the above conundrum: aside from being quite heavily invested in tumorigenesis and therapeutic resistance, CSCs also show self-renewal and fluid clonogenic properties that often define specific TME niches. Further scrutiny of the relationship between CSCs and TMEs also points towards mechanisms that underly tumoral characteristics of metastasis, malignancy, and even resistance. This review summarizes recent advances in NC-enabled targeting of CSCs for more holistic strikes against TMEs and discusses both the current challenges that hinder the clinical application of these strategies as well as the avenues that can further CSC-targeting initiatives. Central role of CSCs in regulation of cellular components within the TME.

Reactive Oxygen Species Scavenging Nanomedicine for the Treatment of Ischemic Heart Disease

Ischemic heart disease (IHD) is the leading cause of disability and mortality worldwide. Reactive oxygen species (ROS) have been shown to play key roles in the progression of diabetes, hypertension, and hypercholesterolemia, which are independent risk factors that lead to atherosclerosis and the development of IHD. Engineered biomaterial-based nanomedicines are under extensive investigation and exploration, serving as smart and multifunctional nanocarriers for synergistic therapeutic effect. Capitalizing on cell/molecule-targeting drug delivery, nanomedicines present enhanced specificity and safety with favorable pharmacokinetics and pharmacodynamics. Herein, the roles of ROS in both IHD and its risk factors are discussed, highlighting cardiovascular medications that have antioxidant properties, and summarizing the advantages, properties, and recent achievements of nanomedicines that have ROS scavenging capacity for the treatment of diabetes, hypertension, hypercholesterolemia, atherosclerosis, ischemia/reperfusion, and myocardial infarction. Finally, the current challenges of nanomedicines for ROS-scavenging treatment of IHD and possible future directions are discussed from a clinical perspective.

Hybrid Membrane-Derived Nanoparticles for Isoliquiritin Enhanced Glioma Therapy

Due to the obstruction and heterogeneity of the blood-brain barrier, the clinical treatment of glioma has been extremely difficult. Isoliquiritigenin (ISL) exhibits antitumor effects, but its low solubility and bioavailability limit its application potential. Herein, we established a nanoscale hybrid membrane-derived system composed of erythrocytes and tumor cells. By encapsulating ISL in hybrid membrane nanoparticles, ISL is expected to be enhanced for the targeting and long-circulation in gliomas therapy. We fused erythrocytes with human glioma cells U251 and extracted the fusion membrane via hypotension, termed as hybrid membrane (HM). HM-camouflaged ISL nanoparticles (ISL@HM NPs) were prepared and featured with FT-IR, SEM, TEM, and DLS particle analysis. As the results concluded, the ISL active pharmaceutical ingredients (APIs) were successfully encapsulated with HM membranes, and the NPs loading efficiency was 38.9 ± 2.99% under maximum entrapment efficiency. By comparing the IC50 of free ISL and NPs, we verified that the solubility and antitumor effect of NPs was markedly enhanced. We also investigated the mechanism of the antitumor effect of ISL@HM NPs, which revealed a marked inhibition of tumor cell proliferation and promotion of senescence and apoptosis of tumor cells of the formulation. In addition, the FSC and WB results examined the effects of different concentrations of ISL@HM NPs on tumor cell disruption and apoptotic protein expression. Finally, it can be concluded that hybridized membrane-derived nanoparticles could prominently increase the solubility of insoluble materials (as ISL), and also enhance its targeting and antitumor effect.

Navigations of the targeting pathway of nanomedicines towards tumor

INTRODUCTION

Nanomedicines (NMs) have emerged as a promising approach for revolutionizing cancer treatment outcomes, mainly due to their benefits in the tumor targeted delivery of therapeutics. The preferential accumulation of NMs in tumor has been widely verified by macroscopical technologies. Accordingly, several classic and emerging targeting mechanisms have been proposed to support the tumor-specific delivery of NMs. The targeting mechanism has been a topic of intensive interest and controversy in the field of NMs development. Especially, the mechanisms by which NMs target tumor remain elusive.

AREA COVERED

This topical review mainly discussed the evolution of the targeting mechanisms, crucial issues associated with each mechanism, and confused debates among the mechanisms. The targeting mechanisms of tumor-specific NMs discussed here include the enhanced permeability and retention (EPR) effect, protein corona-mediated targeting delivery, circulating cell mediated transportation, and transcytosis.

EXPERT OPINION

It is of great significance for ultimate clinical translation to have more comprehensive considerations on the mechanism driving the pathway of NMs toward tumors. Our thoughts in this review are expected to provide comprehensive understanding on the mechanisms and elicit thorough explorations on new mechanism to renovate the knowledge framework of NMs delivery.

Macrophage-Encapsulated Bioorthogonal Nanozymes for Targeting Cancer Cells

Macrophages migrate to tumor sites by following chemoattractant gradients secreted by tumor cells, providing a truly active targeting strategy for cancer therapy. However, macrophage-based delivery faces challenges of cargo loading, control of release, and effects of the payload on the macrophage vehicle. We present a strategy that employs bioorthogonal "nanozymes" featuring transition metal catalysts (TMCs) to provide intracellular "factories" for the conversion of prodyes and prodrugs into imaging agents and chemotherapeutics. These nanozymes solubilize and stabilize the TMCs by embedding them into self-assembled monolayer coating gold nanoparticles. Nanozymes delivered into macrophages were intracellularly localized and retained activity even after prolonged (72 h) incubation. Significantly, nanozyme-loaded macrophages maintained their inherent migratory ability toward tumor cell chemoattractants, efficiently killing cancer cells in cocultures. This work establishes the potential of nanozyme-loaded macrophages for tumor site activation of prodrugs, providing readily tunable dosages and delivery rates while minimizing off-target toxicity of chemotherapeutics.

Antibiotic-Loaded Smart Platelet: A Highly Effective Invisible Mode of Killing Both Antibiotic-Sensitive and -Resistant Bacteria

Microbial pathogenesis is considered one of the most critical health challenges worldwide. Although several antibiotics have been procured and used, the microbes often manage to escape and become resistant to antibiotics. Thus, the discovery of new antibiotics and designing smart approaches toward their delivery are of great importance. In many cases, the delivery agents using foreign chemicals like lipids or polymers induce immunogenic responses of varying degrees and are limited to a shorter circulatory time and burst release. In the current work, we have designed a novel antibiotic delivery system where the antibiotic is encapsulated into a blood component-platelet. Platelets have been previously reported as efficient drug delivery vehicles for targeting cancer cells. On the other hand, during platelet-bacterial interaction, platelets can act as covercytes. Keeping this in mind, smart antibiotic-loaded platelets have been used for killing bacterial cells. The loading of the antibiotic was done using its typical nature of engulfing surrounding small molecules. The water-soluble antibiotics were loaded directly into the platelet, whereas the hydrophobic antibiotics were preloaded in polycaprolactone (FDA-approved polymer)-based nanovesicles to make them solubilized prior to loading inside the platelets. The antibiotic-loaded platelets (containing hydrophilic antibiotics or hydrophobic antibiotic -encapsulated polymer nanoparticles) were found to be stable when studied through platelet aggregometry. The carrier showed bactericidal effects at a significantly lower concentration at which the free antibiotic has negligible efficacy. This could be attributed to the molecular confinement of the antibiotics inside the platelets, therefore causing localization of the drug and leading to efficient activity against bacteria. Interestingly, the smart antibiotic-loaded platelets were capable of killing the resistant strains too at the same lower concentration regime. Therefore, the antibiotic-loaded platelet could emerge as a potential strategy for efficient delivery of antibiotics with a significant reduction of the dose required to achieve the intended antibacterial efficacy. Moreover, this antibiotic delivery method can be very useful to minimize immunogenic responses due to antibiotic administration and to avoid the development of drug resistance due to the invisible mode of delivery.