Phagocyte-membrane-coated and laser-responsive nanoparticles control primary and metastatic cancer by inducing anti-tumor immunity

Advances in cell membrane-based biomimetic nanodelivery systems for natural products

Active components of natural products, which include paclitaxel, curcumin, gambogic acid, resveratrol, triptolide and celastrol, have promising anti-inflammatory, antitumor, anti-oxidant, and other pharmacological activities. However, their clinical application is limited due to low solubility, instability, low bioavailability, rapid metabolism, short half-life, and strong off-target toxicity. To overcome these drawbacks, cell membrane-based biomimetic nanosystems have emerged that avoid clearance by the immune system, enhance targeting, and prolong drug circulation, while also improving drug solubility and bioavailability, enhancing drug efficacy, and reducing side effects. This review summarizes recent advances in the preparation and coating of cell membrane-coated biomimetic nanosystems and in their applications to disease for targeted natural products delivery. Current challenges, limitations, and prospects in this field are also discussed, providing a research basis for the development of multifunctional biomimetic nanosystems for natural products.

Advances in biomimetic nanomaterial delivery systems: harnessing nature's inspiration for targeted drug delivery

The properties of nanomaterials make them promising and advantageous for use in drug delivery systems, but challenges arise from the immune system's recognition of exogenous nanoparticles, leading to their clearance and reduced targeting efficiency. Drawing inspiration from nature, this paper explores biomimetic strategies to transform recognizable nanomaterials into a "camouflaged state." The focal point of this paper is the exploration of bionic nanoparticles, with a focus on cell membrane-coated nanoparticles. These biomimetic structures, particularly those mimicking red blood cells (RBCs), white blood cells (WBCs), platelets, and cancer cells, demonstrate enhanced drug delivery efficiency and prolonged circulation. This article underscores the versatility of these biomimetic structures across diverse diseases and explores the use of hybrid cell membrane-coated nanoparticles as a contemporary trend. This review also investigated exosomes and protein bionic nanoparticles, emphasizing their potential for specific targeting, immune evasion, and improved therapeutic outcomes. We expect that this continued development based on biomimetic nanomaterials will contribute to the efficiency and safety of disease treatment.

Recent Advances in Nanoimmunotherapy by Modulating Tumor-Associated Macrophages for Cancer Therapy

Cancer immunotherapy has yielded remarkable results across a variety of tumor types. Nevertheless, the complex and immunosuppressive microenvironment within solid tumors poses significant challenges to established therapies such as immune checkpoint blockade (ICB) and chimeric antigen receptor T-cell (CAR-T) therapy. Within the milieu, tumor-associated macrophages (TAMs) play a significant role by directly suppressing T-cell functionality and fostering an immunosuppressive environment. Effective regulation of TAMs is, therefore, crucial to enhancing the efficacy of immunotherapies. Various therapeutic strategies targeting TAM modulation have emerged, including blocking TAM recruitment, direct elimination, promoting repolarization toward the M1 phenotype, and enhancing phagocytic capacity against tumor cells. The recently introduced CAR macrophage (CAR-M) therapy opens new possibilities for macrophage-based immunotherapy. Compared with CAR-T, CAR-M may demonstrate superior targeting and infiltration capabilities toward solid tumors. This review predominantly delves into the origin and development process of TAMs, their role in promoting tumor growth, and provides a comprehensive overview of immunotherapies targeting TAMs. It underscores the significance of regulating TAMs in bolstering antitumor therapies while discussing the potential and challenges of developing TAMs as targets for immunotherapy.

Engineered biological nanoparticles as nanotherapeutics for tumor immunomodulation

Biological nanoparticles, or bionanoparticles, are small molecules manufactured in living systems with complex production and assembly machinery. The products of the assembly systems can be further engineered to generate functionalities for specific purposes. These bionanoparticles have demonstrated advantages such as immune system evasion, minimal toxicity, biocompatibility, and biological clearance. Hence, bionanoparticles are considered the new paradigm in nanoscience research for fabricating safe and effective nanoformulations for therapeutic purposes. Harnessing the power of the immune system to recognize and eradicate malignancies is a viable strategy to achieve better therapeutic outcomes with long-term protection from disease recurrence. However, cancerous tissues have evolved to become invisible to immune recognition and to transform the tumor microenvironment into an immunosuppressive dwelling, thwarting the immune defense systems and creating a hospitable atmosphere for cancer growth and progression. Thus, it is pertinent that efforts in fabricating nanoformulations for immunomodulation are mindful of the tumor-induced immune aberrations that could render cancer nanotherapy inoperable. This review systematically categorizes the immunosuppression mechanisms, the regulatory immunosuppressive cellular players, and critical suppressive molecules currently targeted as breakthrough therapies in the clinic. Finally, this review will summarize the engineering strategies for affording immune moderating functions to bionanoparticles that tip the tumor microenvironment (TME) balance toward cancer elimination, a field still in the nascent stage.

Effective glioblastoma immune sonodynamic treatment mediated by macrophage cell membrane cloaked biomimetic nanomedicines

Glioblastoma (GBM) as one of the most lethal brain tumours, remains poor therapeutic index due to its typical characters including heterogeneous, severe immune suppression as well as the existence of blood brain barrier (BBB). Immune sonodynamic (ISD) therapy combines noninvasive sonodynamic therapy with immunotherapy, which has great prospects for the combinational treatment of GBM. Herein, we develop macrophage cell membrane cloaked reactive oxygen species (ROS) responsive biomimetic nanoparticles, co-delivering of sonosensitizer Ce6 and JQ1 (a bromo-domain protein 4 (BRD4) inhibitor which can down-regulate PD-L1) and realizing potent GBM ISD therapy. The ApoE peptide decorated macrophage membrane coating endows these biomimetic nanoparticles with low immunogenicity, efficient BBB permeability, prolonged blood circulation half-live and good biocompatibility. The ROS responsive polymeric inner core could be readily degraded as triggered by excessive ROS under the ultrasound once they accumulated in tumour cells, fast release encapsulated drugs. The generation of ROS not only killed tumour cells via sonodynamic therapy, but also induced immunogenic cell death (ICD) and further activated the anti-tumour immune response. The released JQ1 inhibited tumour cell proliferation and augmented the immune activities by inhibiting the PD-L1 expression on the surface of tumour cells. The cascade sonodynamic and immune therapy resulted in significantly improved median survival time in both orthotopic GL261 and PTEN deficient immunosuppressive CT2A GBM mice models. Therefore, our developed biomimetic nanoparticle platform provides a promising combinational therapy strategy to treat immune suppressive GBM.

Macrophage membrane-coated nanoparticles for the treatment of infectious diseases

Infectious diseases severely threaten human health, and traditional treatment techniques face multiple limitations. As an important component of immune cells, macrophages display unique biological properties, such as biocompatibility, immunocompatibility, targeting specificity, and immunoregulatory activity, and play a critical role in protecting the body against infections. The macrophage membrane-coated nanoparticles not only maintain the functions of the inner nanoparticles but also inherit the characteristics of macrophages, making them excellent tools for improving drug delivery and therapeutic implications in infectious diseases (IDs). In this review, we describe the characteristics and functions of macrophage membrane-coated nanoparticles and their advantages and challenges in ID therapy. We first summarize the pathological features of IDs, providing insight into how to fight them. Next, we focus on the classification, characteristics, and preparation of macrophage membrane-coated nanoparticles. Finally, we comprehensively describe the progress of macrophage membrane-coated nanoparticles in combating IDs, including drug delivery, inhibition and killing of pathogens, and immune modulation. At the end of this review, a look forward to the challenges of this aspect is presented.

Cell membrane coated nanoparticles as a biomimetic drug delivery platform for enhancing cancer immunotherapy

Cancer immunotherapy, a burgeoning modality for cancer treatment, operates by activating the autoimmune system to impede the growth of malignant cells. Although numerous immunotherapy strategies have been employed in clinical cancer therapy, the resistance of cancer cells to immunotherapeutic medications and other apprehensions impede the attainment of sustained advantages for most patients. Recent advancements in nanotechnology for drug delivery hold promise in augmenting the efficacy of immunotherapy. However, the efficacy is currently constrained by the inadequate specificity of delivery, low rate of response, and the intricate immunosuppressive tumor microenvironment. In this context, the investigation of cell membrane coated nanoparticles (CMNPs) has revealed their ability to perform targeted delivery, immune evasion, controlled release, and immunomodulation. By combining the advantageous features of natural cell membranes and nanoparticles, CMNPs have demonstrated their unique potential in the realm of cancer immunotherapy. This review aims to emphasize recent research progress and elucidate the underlying mechanisms of CMNPs as an innovative drug delivery platform for enhancing cancer immunotherapy. Additionally, it provides a comprehensive overview of the current immunotherapeutic strategies involving different cell membrane types of CMNPs, with the intention of further exploration and optimization.

Cancer Nanovaccines: Nanomaterials and Clinical Perspectives

Cancer nanovaccines represent a promising frontier in cancer immunotherapy, utilizing nanotechnology to augment traditional vaccine efficacy. This review comprehensively examines the current state-of-the-art in cancer nanovaccine development, elucidating innovative strategies and technologies employed in their design. It explores both preclinical and clinical advancements, emphasizing key studies demonstrating their potential to elicit robust anti-tumor immune responses. The study encompasses various facets, including integrating biomaterial-based nanocarriers for antigen delivery, adjuvant selection, and the impact of nanoscale properties on vaccine performance. Detailed insights into the complex interplay between the tumor microenvironment and nanovaccine responses are provided, highlighting challenges and opportunities in optimizing therapeutic outcomes. Additionally, the study presents a thorough analysis of ongoing clinical trials, presenting a snapshot of the current clinical landscape. By curating the latest scientific findings and clinical developments, this study aims to serve as a comprehensive resource for researchers and clinicians engaged in advancing cancer immunotherapy. Integrating nanotechnology into vaccine design holds immense promise for revolutionizing cancer treatment paradigms, and this review provides a timely update on the evolving landscape of cancer nanovaccines.

Recent Progress of Bioinspired Cell Membrane in Cancer Immunotherapy

By modifying immune cells, immunotherapy can activate immune response to establish long-term immune memory and prevent tumor recurrence. However, their effectiveness is largely constricted by the poor immunogenicity, immune escape, and immune tolerance of the tumor. This is related to the characteristics of the tumor itself, such as genome instability and mutation. The combination of various nanocarriers with tumor immunotherapy is beneficial for overcoming the shortcomings of traditional immunotherapy. Nanocarriers coated by cell membranes can extend blood circulation time, improve ability to evade immune clearance, and enhance targeting, thus significantly enhancing the efficacy of immunotherapy and showing great potential in tumor immunotherapy. This article reviews the application research progress of different types of cell membrane-modified nanocarriers in tumor immunotherapy, immunotherapy combination therapy, and tumor vaccines, and provides prospects for future research.

Brain Delivery of Biomimetic Phosphorus Dendrimer/Antibody Nanocomplexes for Enhanced Glioma Immunotherapy via Immune Modulation of T Cells and Natural Killer Cells

Fully mobilizing the activities of multiple immune cells is crucial to achieve the desired tumor immunotherapeutic efficacy yet still remains challenging. Herein, we report a nanomedicine formulation based on phosphorus dendrimer (termed AK128)/programmed cell death protein 1 antibody (aPD1) nanocomplexes (NCs) that are camouflaged with M1-type macrophage cell membranes (M1m) for enhanced immunotherapy of orthotopic glioma. The constructed AK128-aPD1@M1m NCs with a mean particle size of 160.3 nm possess good stability and cytocompatibility. By virtue of the decorated M1m having α4 and β1 integrins, the NCs are able to penetrate the blood-brain barrier to codeliver both AK128 with intrinsic immunomodulatory activity and aPD1 to the orthotopic glioma with prolonged blood circulation time. We show that the phosphorus dendrimer AK128 can boost natural killer (NK) cell proliferation in peripheral blood mononuclear cells, while the delivered aPD1 enables immune checkpoint blockade (ICB) to restore the cytotoxic T cells and NK cells, thus promoting tumor cell apoptosis and simultaneously decreasing the tumor distribution of regulatory T cells vastly for improved glioma immunotherapy. The developed nanomedicine formulation with a simple composition achieves multiple modulations of immune cells by utilizing the immunomodulatory activity of nanocarrier and antibody-mediated ICB therapy, providing an effective strategy for cancer immunotherapy.

Orchestrating Precision within the Tumor Microenvironment by Biomimetic Nanoprodrugs for Effective Tumor Therapy

Malignant tumors are still one of the most deadly diseases that threaten human life and health. However, developing new drugs is challenging due to lengthy trials, funding constraints, and regulatory approval procedures. Consequently, researchers have devoted themselves to transforming some clinically approved old drugs into antitumor drugs with certain active ingredients, which have become an attractive alternative. Disulfiram (DSF), an antialcohol medication, can rapidly metabolize in the physiological environment into diethyldithiocarbamate (DTC) which can readily react with Cu2+ ions in situ to form the highly toxic bis(N,N-diethyldithiocarbamate)-copper(II) (CuET) complex. In this study, DSF is loaded into mesoporous dopamine nanocarriers and surface-chelated with tannin and Cu2+ to construct M-MDTC nanoprodrugs under the camouflage of K7 tumor cell membranes. After intravenous injection, M-MDTC nanoprodrugs successfully reach the tumor sites with the help of mediated cell membranes. Under slightly acidic pH and photothermal stimulation conditions, DSF and Cu2+ are simultaneously released, forming a highly toxic CuET to kill tumor cells in situ. The generated CuET can also induce immunogenic cell death of tumor cells, increase the proportion of CD86+ CD80+ cells, and promote dendritic cell maturation. In vitro and in vivo studies of M-MDTC nanoprodrugs have shown excellent tumor-cell-killing ability and solid tumor suppression. This approach enables in situ amplification of chemotherapy in the tumor microenvironment, achieving an effective antitumor treatment.

Enhanced EPR effects by tumour stromal cell mimicking nanoplatform on invasive pituitary adenoma

Rapid advances in nanomedicine have enabled potential applications in cancer therapy. The enhanced permeability and retention (EPR) effect is the primary rationale for the passive targeting of nanoparticles in oncology. However, growing evidence indicates that the accumulation of nanomaterials via the EPR effect could be more efficient. Inspired by our clinical observation of the Gap Junction connecpion between folliculostellate cells and pituitary adenoma cells, we designed a novel drug delivery system that targets tumours by coating folliculostellate cell (FS) membranes onto PLGA nanoparticles (NPs). The resulting FSNPs, inheriting membrane proteins from the folliculostellate cell membrane, significantly enhanced the EPR effect compared to nanoparticles without cancer cell membranes. We further demonstrated that mitotane encapsulation improved the therapeutic efficacy of mitotane in both heterotopic and orthotopic pituitary adenoma models. Owing to its significant efficacy, our FS cell membrane-coated nanoplatforms has the potential to be translated into clinical applications for the treatment of invasive pituitary adenoma.

Zwitterionic Injectable Hydrogel-Combined Chemo- and Immunotherapy Medicated by Monomolecular Micelles to Effectively Prevent the Recurrence of Tumor Post Operation

Surgical resection remains the most common method of tumor treatment; however, the high recurrence and metastasis after surgery need to be solved urgently. Herein, we report an injectable zwitterionic hydrogel based on "thiol-ene" click chemistry containing doxorubicin (DOX) and a macrophage membrane (MM)-coated 1-methyl-tryptophan (1-MT)-loaded polyamide-amine dendrimer (P-DOX/1MT) for preventing the postoperative recurrence of tumors. The results indicated that P-DOX/1MT@MM exhibited enhanced recognition and uptake of the dendrimer by tumor cells and induced the immunogenic cell death. In the mice tumor model, the P-DOX/1MT@MM-Gel exhibited high therapeutic efficiency, which could significantly reduce the recurrence of the tumor, including suppressing tumor growth, promoting dendritic cell maturation, and increasing tumor-infiltrating cytotoxic T lymphocytes. The mechanism analysis revealed that the hydrogel greatly reduces the side effects to normal tissues and significantly improves its therapeutic effect. 1MT in the hydrogel is released more rapidly, improving the tumor suppressor microenvironment and increasing the tumor cell sensitivity to DOX. Then, the DOX in the P-DOX/1MT@MM effectively eliminatedo the residual tumor cells and exerted enhanced toxicity. In conclusion, this novel injectable hydrogel that combines chemotherapy and immunotherapy has the property of sequential drug release and is a promising strategy for preventing the postoperative recurrence of tumors.

Cell membrane-based biomimetic technology for cancer phototherapy: Mechanisms, recent advances and perspectives

Despite significant advances in medical technology and antitumour treatments, the diagnosis and treatment of tumours have undergone remarkable transformations. Noninvasive phototherapy methods, such as photodynamic therapy (PDT) and photothermal therapy (PTT), have gained significant interest in antitumour medicine. However, traditional photosensitisers or photothermal agents face challenges like immune system recognition, rapid clearance from the bloodstream, limited tumour accumulation, and phototoxicity concerns. Researchers combine photosensitisers or photothermal agents with natural cell membranes to overcome these obstacles to create a nano biomimetic therapeutic platform. When used to coat nanoparticles, red blood cells, platelets, cancer cells, macrophages, lymphocytes, and bacterial outer membranes could provide prolonged circulation, tumour targeting, immune stimulation, or antigenicity. This article covers the principles of cellular membrane biomimetic nanotechnology and phototherapy, along with recent advancements in applying nano biomimetic technology to PDT, PTT, PCT, and combined diagnosis and treatment. Furthermore, the challenges and issues of using nano biomimetic nanoparticles in phototherapy are discussed. STATEMENT OF SIGNIFICANCE: Currently, there has been significant progress in the field of cell membrane biomimetic technology. Researchers are exploring its potential application in tumor diagnosis and treatment through phototherapy. Scholars have conducted extensive research on combining cell membrane technology and phototherapy in anticancer diagnosis and treatment. This review aims to highlight the mechanisms of phototherapy and the latest advancements in single phototherapy (PTT, PDT) and combination phototherapy (PCT, PRT, and PIT), as well as diagnostic approaches. The review provides an overview of various cell membrane technologies, including RBC membranes, platelet membranes, macrophage cell membranes, tumour cell membranes, bacterial membranes, hybrid membranes, and their potential for anticancer applications under phototherapy. Lastly, the review discusses the challenges and future directions in this field.

Synergistic reinforcement of immunogenic cell death and transformation of tumor-associated macrophages via an M1-type macrophage membrane-camouflaged ferrous-supply-regeneration nanoplatform

The immune system's role in tumor growth and spread has led to the importance of activating immune function in tumor therapy. We present a strategy using an M1-type macrophage membrane-camouflaged ferrous-supply-regeneration nanoplatform (M1mDDTF) to synergistically reinforce immunogenic cell death (ICD) and transform tumor-associated macrophages (TAMs) against tumors. The M1mDDTF nanoparticles consist of doxorubicin-loaded dendritic mesoporous silica nanoparticles chelated with FeIII-tannic acid (FeIIITA) and coated with M1-type macrophage membranes. In the acidic tumor microenvironment, FeIIITA releases Fe2+ and generates ·OH, aided by near infrared irradiation for enhanced doxorubicin release. Furthermore, the M1mDDTF nanoplatform not only directly kills tumor cells but stimulates ICD, which can increase the proportion of CD86+ CD80+ cells and promote dendritic cell maturation. Particularly, the M1mDDTF nanoplatform can also promote the gradual polarization of TAMs into the M1-type and promote tumor cell killing. This study demonstrates the safety and multifunctionality of M1mDDTF nanoparticles, highlighting their potential for clinical tumor treatment. STATEMENT OF SIGNIFICANCE: Malignant tumors are a global concern and a major cause of death. Nanoparticles' passive targeting is ineffective and hindered by reticuloendothelial system clearance. Therefore, enhancing nanoparticle accumulation in tumors while minimizing toxicity is a challenge. Coating nanoparticles with cell membranes enhances biocompatibility, immune evasion, and specific targeting. This approach has led to the development of numerous cell membrane-mimicking nanomaterials with remarkable properties and functions. This study developed an M1-type macrophage membrane-camouflaged ferrous-supply-regeneration nanoplatform, boosting immunogenic cell death and transforming tumor-associated macrophages. Tannic acid in the tumor microenvironment reduced Fe3+ to Fe2+, generating ·OH. M1mDDTF nanosystem induced M1-type macrophage polarization, inhibiting tumor growth and triggering immune cell death. Safe and versatile, these M1mDDTF nanoparticles hold promise for clinical tumor treatment.

Advances in Composite Biofilm Biomimetic Nanodrug Delivery Systems for Cancer Treatment

Single biofilm biomimetic nanodrug delivery systems based on single cell membranes, such as erythrocytes and cancer cells, have immune evasion ability, good biocompatibility, prolonged blood circulation, and high tumor targeting. Because of the different characteristics and functions of each single cell membrane, more researchers are using various hybrid cell membranes according to their specific needs. This review focuses on several different types of biomimetic nanodrug-delivery systems based on composite biofilms and looks forward to the challenges and possible development directions of biomimetic nanodrug-delivery systems based on composite biofilms to provide reference and ideas for future research.

Recent Advances in Biomedical Nanotechnology Related to Natural Products

Natural product processing via nanotechnology has opened the door to innovative and significant applications in medical fields. On one hand, plants-derived bioactive ingredients such as phenols, pentacyclic triterpenes and flavonoids exhibit significant pharmacological activities, on another hand, most of them are hydrophobic in nature, posing challenges to their use. To overcome this issue, nanoencapsulation technology is employed to encapsulate these lipophilic compounds and enhance their bioavailability. In this regard, various nano-sized vehicles, including degradable functional polymer organic compounds, mesoporous silicon or carbon materials, offer superior stability and retention for bioactive ingredients against decomposition and loss during delivery as well as sustained release. On the other hand, some naturally occurring polymers, lipids and even microorganisms, which constitute a significant portion of Earth's biomass, show promising potential for biomedical applications as well. Through nano-processing, these natural products can be developed into nano-delivery systems with desirable characteristics for encapsulation a wide range of bioactive components and therapeutic agents, facilitating in vivo drug transport. Beyond the presentation of the most recent nanoencapsulation and nano-processing advancements with formulations mainly based on natural products, this review emphasizes the importance of their physicochemical properties at the nanoscale and their potential in disease therapy.

Cellular-Membrane-Derived Vesicles for Cancer Immunotherapy

The medical community is constantly searching for new and innovative ways to treat cancer, and cellular-membrane-derived artificial vesicles are emerging as a promising avenue for cancer immunotherapy. These vesicles, which are derived from mammal and bacteria cell membranes, offer a range of benefits, including compatibility with living organisms, minimal immune response, and prolonged circulation. By modifying their surface, manipulating their genes, combining them with other substances, stimulating them externally, and even enclosing drugs within them, cellular vesicles have the potential to be a powerful tool in fighting cancer. The ability to merge drugs with diverse compositions and functionalities in a localized area is particularly exciting, as it offers a way to combine different immunotherapy treatments for maximum impact. This review contains information on the various sources of these vesicles and discusses some recent developments in cancer immunotherapy using this promising technology. While there are still obstacles to overcome, the possibilities for cellular vesicles in cancer treatment are truly exciting.

Biomimetic nanoplatform with selectively positioned indocyanine green for accurate sentinel lymph node imaging

The status of draining lymph nodes (LNs) is critical for determining the treatment and prognosis of cancer that spreads through the lymphatic system. Indocyanine green (ICG) fluorescence imaging has been widely used in sentinel LN (SLN) biopsy technology and has shown favorable effects. However, this too has its own limitations, such as fluorescence instability and diffusion imaging. In this study, we developed macrophage cell membrane-camouflaged ICG-loaded biomimetic nanoparticles (M@F127-ICG) for accurate SLN imaging. ICG selectively positioned at the hydrophobic-hydrophilic interfaces of pluronic F127 micelles protected itself from quenching in aqueous solution, thereby maintaining fluorescence stability and improving fluorescence intensity. In addition, to further improve the aggregation in SLN, the micellar surface was coated with a layer of biomimetic macrophage cell membrane to target LN-resident macrophages. In vivo fluorescence imaging demonstrated that M@F127-ICG significantly enhanced the fluorescence signal and improved the imaging efficiency of SLN. Thus, selectively positioning ICG in the biomimetic nanoplatform enhanced the fluorescence intensity and stability, providing a novel tracer for timely and accurate SLN imaging.

A detailed insight of the tumor targeting using nanocarrier drug delivery system

Human struggle against the deadly disease conditions is continued since ages. The contribution of science and technology in fighting against these diseases cannot be ignored exclusively due to the invention of novel procedure and products, extending their size ranges from micro to nano. Recently nanotechnology has been gaining more consideration for its ability to diagnose and treat different cancers. Different nanoparticles have been used to evade the issues related with conservative anticancer delivery systems, including their nonspecificity, adverse effects and burst release. These nanocarriers including, solid lipid nanoparticles (SLNs), liposomes, nano lipid carriers (NLCs), nano micelles, nanocomposites, polymeric and magnetic nanocarriers, have brought revolutions in antitumor drug delivery. Nanocarriers improved the therapeutic efficacy of anticancer drugs with better accumulation at the specific site with sustained release, improved bioavailability and apoptosis of the cancer cells while bypassing the normal cells. In this review, the cancer targeting techniques and surface modification on nanoparticles are discussed briefly with possible challenges and opportunities. It can be concluded that understanding the role of nanomedicine in tumor treatment is significant, and therefore, the modern progressions in this arena is essential to be considered for a prosperous today and an affluent future of tumor patients.

Advances in Targeting Drug Biological Carriers for Enhancing Tumor Therapy Efficacy

Chemotherapy drugs continue to be the main component of oncology treatment research and have been proven to be the main treatment modality in tumor therapy. However, the poor delivery efficiency of cancer therapeutic drugs and their potential off-target toxicity significantly limit their effectiveness and extensive application. The recent integration of biological carriers and functional agents is expected to camouflage synthetic biomimetic nanoparticles for targeted delivery. The promising candidates, including but not limited to red blood cells and their membranes, platelets, tumor cell membrane, bacteria, immune cell membrane, and hybrid membrane are typical representatives of biological carriers because of their excellent biocompatibility and biodegradability. Biological carriers are widely used to deliver chemotherapy drugs to improve the effectiveness of drug delivery and therapeutic efficacy in vivo, and tremendous progress is made in this field. This review summarizes recent developments in biological vectors as targeted drug delivery systems based on microenvironmental stimuli-responsive release, thus highlighting the potential applications of target drug biological carriers. The review also discusses the possibility of clinical translation, as well as the exploitation trend of these target drug biological carriers.

Cell membrane biomimetic nanoparticles in drug delivery

Despite the efficiency of nanoparticle (NP) therapy, in vivo investigations have shown that it does not perform as well as in vitro. In this case, NP confronts many defensive hurdles once they enter the body. The delivery of NP to sick tissue is inhibited by these immune-mediated clearance mechanisms. Hence, using a cell membrane to hide NP for active distribution offers up a new path for focused treatment. These NPs are better able to reach the disease's target location, leading to enhanced therapeutic efficacy. In this emerging class of drug delivery vehicles, the inherent relation between the NPs and the biological components obtained from the human body was utilized, which mimic the properties and activities of native cells. This new technology has shown the viability of using biomimicry to evade immune system-provided biological barriers, with an emphasis on restricting clearance from the body before reaching its intended target. Furthermore, by providing signaling cues and transplanted biological components that favorably change the intrinsic immune response at the disease site, the NPs would be capable interacting with immune cells regarding the biomimetic method. Thus, we aimed to provide a current landscape and future trends of biomimetic NPs in drug delivery.

Sequence-Responsive Multifunctional Supramolecular Nanomicelles Act on the Regression of TNBC and Its Lung Metastasis via Synergic Pyroptosis-Mediated Immune Activation

Design of effective nanodrugs to modulate the immunosuppression of tumor microenvironment is a desirable approach to boost the clinical tumor-therapeutic effect. Supramolecular nanomicelles PolyMN-TO-8, which are constructed by self-assembling supramolecular host MTX-MPEG2000, guest NPX-2S, and TO-8 through hydrophobic forces, have excellent stability and responsiveness to carboxylesterase and glutathione in turn. In vivo studies validate that PolyMN-TO-8 enable to trigger pyroptosis-mediated immunogenic cell death under laser, avoiding the occurrence of immune dysregulation simultaneously. This therapeutic mode strengthens dendritic cells' maturation and accelerates the infiltration of CD8+ T cells into tumors through moderate activation of pro-inflammatory factors with elimination of immune-escape, ultimately making the tumor inhibition rate as high as 87.44% via synergistic functions of photodynamic therapy, photothermal therapy, chemotherapy, etc. The loss of immune-escape quickens the infiltration of CD8+ T cells into lungs, and further eschews the generation of tumor nodules in it. Chemotherapy, the release of interferon-γ, and immune memory effect also strengthen the defense against metastasis. The generation of O2 catalyzed by PolyMN-TO-8 under laser is indispensable for tumor metastasis inhibition undoubtedly.

A covalent organic framework-derived M1 macrophage mimic nanozyme for precise tumor-targeted imaging and NIR-II photothermal catalytic chemotherapy

Nanoprobes for efficient tumor-targeted imaging and therapy are urgently needed for clinical tumor theranostics. Herein, inspired by the heterogeneity of the tumor microenvironment, we report a covalent organic framework (COF)-derived biomimetic nanozyme for precise tumor-targeted imaging and NIR-II photothermal-catalysis-enhanced chemotherapy (PTCEC). Using a crystalline nanoscale COF as the precursor, a peroxidase-like porous N-doped carbonous nanozyme (PNC) was obtained, which was cloaked with an M1 macrophage cell membrane (M1m) to create a multifunctional biomimetic nanoprobe for tumor-targeted imaging and therapy. The M1m coating enabled the nanoprobe to target cancer cells and tumor tissues for highly efficient tumor imaging and drug delivery. The peroxidase-like activity of the PNC allowed for the conversion of intratumoral H2O2 into toxic ˙OH that synergized with its NIR-II photothermal effect to strengthen the chemotherapy. Therefore, highly efficient tumor-targeted imaging and NIR-II PTCEC were realized with an M1 macrophage mimic nanoprobe. This work provides a feasible tactic for a biomimetic theranostic nanoprobe and will inspire the development of new bioactive nanomaterials for clinical tumor theranostic applications.

Genetically Engineered Cell Membrane-Coated Nanoparticles with High-Density Customized Membrane Receptor for High-Performance Drug Lead Discovery

Cell membrane coating strategies have been increasingly researched due to their unique capabilities of biomimicry and biointerfacing, which can mimic the functionality of the original source cells in vivo but fail to provide customized nanoparticle surfaces with new or enhanced capabilities beyond natural cells. However, the field of drug lead discovery necessitates the acquisition of sufficient surface density of specific target membrane receptors, presenting a heightened demand for this technology. In this study, we developed a novel approach to fabricate high density of fibroblast growth factor receptor 4 (FGFR4) cell membrane-coated nanoparticles through covalent site-specific immobilization between genetically engineered FGFR4 with HaloTag anchor on cell membrane and chloroalkane-functionalized magnetic nanoparticles. This technique enables efficient screening of tyrosine kinase inhibitors from natural products. And the enhanced density of FGFR4 on the surface of nanoparticles were successfully confirmed by Western blot assay and confocal laser scanning microscopy. Further, the customized nanoparticles demonstrated exceptional sensitivity (limit of detection = 0.3 × 10-3 μg mL-1). Overall, the proposed design of a high density of membrane receptors, achieved through covalent site-specific immobilization with a HaloTag anchor, demonstrates a promising strategy for the development of cell membrane surface engineering. This approach highlights the potential of cell membrane coating technology for facilitating the advanced extraction of small molecules for drug discovery.

Four Ounces Can Move a Thousand Pounds: The Enormous Value of Nanomaterials in Tumor Immunotherapy

The application of nanomaterials in healthcare has emerged as a promising strategy due to their unique structural diversity, surface properties, and compositional diversity. In particular, nanomaterials have found a significant role in improving drug delivery and inhibiting the growth and metastasis of tumor cells. Moreover, recent studies have highlighted their potential in modulating the tumor microenvironment (TME) and enhancing the activity of immune cells to improve tumor therapy efficacy. Various types of nanomaterials are currently utilized as drug carriers, immunosuppressants, immune activators, immunoassay reagents, and more for tumor immunotherapy. Necessarily, nanomaterials used for tumor immunotherapy can be grouped into two categories: organic and inorganic nanomaterials. Though both have shown the ability to achieve the purpose of tumor immunotherapy, their composition and structural properties result in differences in their mechanisms and modes of action. Organic nanomaterials can be further divided into organic polymers, cell membranes, nanoemulsion-modified, and hydrogel forms. At the same time, inorganic nanomaterials can be broadly classified as nonmetallic and metallic nanomaterials. The current work aims to explore the mechanisms of action of these different types of nanomaterials and their prospects for promoting tumor immunotherapy.

Biomimetic biomineralization nanoplatform-mediated differentiation therapy and phototherapy for cancer stem cell inhibition and antitumor immunity activation

Growing evidence suggests that the presence of cancer stem cells (CSCs) is a major challenge in current tumor treatments, especially the transition from non-CSCs to differentiation of CSCs for evading conventional therapies and driving metastasis. Here we propose a therapeutic strategy of synergistic differentiation therapy and phototherapy to induce differentiation of CSCs into mature tumor cells by differentiation inducers and synergistic elimination of them and normal cancer cells through phototherapy. In this work, we synthesized a biomimetic nanoplatform loaded with IR-780 and all-trans retinoic acid (ATRA) via biomineralization. This method can integrate aluminum ions into small-sized protein carriers to form nanoclusters, which undergo responsive degradation under acidic conditions and facilitate deep tumor penetration. With the help of CSC differentiation induced by ATRA, IR-780 inhibited the self-renewal of CSCs and cancer progression by generating hyperthermia and reactive oxygen species in a synergistic manner. Furthermore, ATRA can boost immunogenic cell death induced by phototherapy, thereby strongly causing a systemic anti-tumor immune response and efficiently eliminating CSCs and tumor cells. Taken together, this dual strategy represents a new paradigm of targeted eradication of CSCs and tumors by inducing CSC differentiation, improving photothermal therapy/photodynamic therapy and enhancing antitumor immunity.

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.

M1 Macrophage-Biomimetic Targeted Nanoparticles Containing Oxygen Self-Supplied Enzyme for Enhancing the Chemotherapy

Tumor hypoxia is considered one of the key causes of the ineffectiveness of various strategies for cancer treatment, and the non-specific effects of chemotherapy drugs on tumor treatment often lead to systemic toxicity. Thus, we designed M1 macrophage-biomimetic-targeted nanoparticles (DOX/CAT@PLGA-M1) which contain oxygen self-supplied enzyme (catalase, CAT) and chemo-therapeutic drug (doxorubicin, DOX). The particle size of DOX/CAT@PLGA-M1 was 202.32 ± 2.27 nm (PDI < 0.3). DOX/CAT@PLGA-M1 exhibited a characteristic core-shell bilayer membrane structure. The CAT activity of DOX/CAT@PLGA-M1 was 1000 (U/mL), which indicated that the formation of NPs did not significantly affect its enzymatic activity. And in vitro drug release showed that the cumulative release rate of DOX/CAT@PLGA-M1 was enhanced from 26.93% to 50.10% in the release medium of hydrogen peroxide, which was attributed to the reaction of CAT in the NPs. DOX/CAT@PLGA-M1 displayed a significantly higher uptake in 4T1 cells, because VCAM-1 in tumor cells interacted with specific integrin (α4 and β1), and thereby achieved tumor sites. And the tumor volume of the DOX/CAT@PLGA-M1 group was significantly reduced (0.22 cm3), which further proved the active targeting effect of the M1 macrophage membrane. Above all, a novel multifunctional nano-therapy was developed which improved tumor hypoxia and obtained tumor targeting activity.

Biomimetic Cell-Derived Nanoparticles: Emerging Platforms for Cancer Immunotherapy

Cancer immunotherapy can significantly prevent tumor growth and metastasis by activating the autoimmune system without destroying normal cells. Although cancer immunotherapy has made some achievements in clinical cancer treatment, it is still restricted by systemic immunotoxicity, immune cell dysfunction, cancer heterogeneity, and the immunosuppressive tumor microenvironment (ITME). Biomimetic cell-derived nanoparticles are attracting considerable interest due to their better biocompatibility and lower immunogenicity. Moreover, biomimetic cell-derived nanoparticles can achieve different preferred biological effects due to their inherent abundant source cell-relevant functions. This review summarizes the latest developments in biomimetic cell-derived nanoparticles for cancer immunotherapy, discusses the applications of each biomimetic system in cancer immunotherapy, and analyzes the challenges for clinical transformation.

Erythrocyte-cancer hybrid membrane-coated reduction-sensitive nanoparticles for enhancing chemotherapy efficacy in breast cancer

Cell-membrane-coated biomimetic nanoparticles (NPs) have attracted great attention due to their prolonged circulation time, immune escape mechanisms and homotypic targeting properties. Biomimetic nanosystems from different types of cell -membranes (CMs) can perform increasingly complex tasks in dynamic biological environments thanks to specific proteins and other properties inherited from the source cells. Herein, we coated doxorubicin (DOX)-loaded reduction-sensitive chitosan (CS) NPs with 4T1 cancer cell -membranes (CCMs), red blood cell -membranes (RBCMs) and hybrid erythrocyte-cancer membranes (RBC-4T1CMs) to enhance the delivery of DOX to breast cancer cells. The physicochemical properties (size, zeta potential and morphology) of the resulting RBC@DOX/CS-NPs, 4T1@DOX/CS-NPs and RBC-4T1@DOX/CS-NPs, as well as their cytotoxic effect and cellular NP uptake in vitro were thoroughly characterized. The anti-cancer therapeutic efficacy of the NPs was evaluated using the orthotopic 4T1 breast cancer model in vivo. The experimental results showed that DOX/CS-NPs had a DOX-loading capacity of 71.76 ± 0.87 %, and that coating of DOX/CS-NPs with 4T1CM significantly increased the NP uptake and cytotoxic effect in breast cancer cells. Interestingly, by optimizing the ratio of RBCMs:4T1CMs, it was possible to increase the homotypic targeting properties towards breast cancer cells. Moreover, in vivo tumor studies showed that compared to control DOX/CS-NPs and free DOX, both 4T1@DOX/CS-NPs and RBC@DOX/CS-NPs significantly inhibited tumor growth and metastasis. However, the effect of 4T1@DOX/CS-NPs was more prominent. Moreover, CM-coating reduced the uptake of NPs by macrophages and led to rapid clearance from the liver and lungs in vivo, compared to control NPs. Our results suggest that specific self-recognition to source cells resulting in homotypic targeting increased the uptake and the cytotoxic capacity of 4T1@DOX/CS-NPs by breast cancer cells in vitro and in vivo. In conclusion, tumor-disguised CM-coated DOX/CS-NPs exhibited tumor homotypic targeting and anti-cancer properties, and were superior over targeting with RBC-CM or RBC-4T1 hybrid membranes, suggesting that the presence of 4T1-CM is critical for treatment outcome.

Design of Disintegrable Nanoassemblies to Release Multiple Small-Sized Nanoparticles

The therapeutic and diagnostic effects of nanoparticles depend on the efficiency of their delivery to targeted tissues, such as tumors. The size of nanoparticles, among other characteristics, plays a crucial role in determining their tissue penetration and retention. Small nanoparticles may penetrate deeper into tumor parenchyma but are poorly retained, whereas large ones are distributed around tumor blood vessels. Thus, compared to smaller individual nanoparticles, assemblies of such nanoparticles due to their larger size are favorable for prolonged blood circulation and enhanced tumor accumulation. Upon reaching the targeted tissues, nanoassemblies may dissociate at the target region and release the smaller nanoparticles, which is beneficial for their distribution at the target site and ultimate clearance. The recent emerging strategy that combines small nanoparticles into larger, biodegradable nanoassemblies has been demonstrated by several groups. This review summarizes a variety of chemical and structural designs for constructing stimuli-responsive disintegrable nanoassemblies as well as their different disassembly routes. These nanoassemblies have been applied as demonstrators in the fields of cancer therapy, antibacterial infection, ischemic stroke recovery, bioimaging, and diagnostics. Finally, we summarize stimuli-responsive mechanisms and their corresponding nanomedicine designing strategies, and discuss potential challenges and barriers towards clinical translation.

Active targeting schemes for nano-drug delivery systems in osteosarcoma therapeutics

Osteosarcoma, the most common malignant tumor of the bone, seriously influences people's lives and increases their economic burden. Conventional chemotherapy drugs achieve limited therapeutic effects owing to poor targeting and severe systemic toxicity. Nanocarrier-based drug delivery systems can significantly enhance the utilization efficiency of chemotherapeutic drugs through targeting ligand modifications and reduce the occurrence of systemic adverse effects. A variety of ligand-modified nano-drug delivery systems have been developed for different targeting schemes. Here we review the biological characteristics and the main challenges of current drug therapy of OS, and further elaborate on different targeting schemes and ligand selection for nano-drug delivery systems of osteosarcoma, which may provide new horizons for the development of advanced targeted drug delivery systems in the future.

Membrane-camouflaged biomimetic nanoparticles as potential immunomodulatory solutions for sepsis: An overview

Sepsis is a life-threatening organ dysfunction due to dysregulated host responses induced by infection. The presence of immune disturbance is key to the onset and development of sepsis but has remarkably limited therapeutic options. Advances in biomedical nanotechnology have provided innovative approaches to rebalancing the host immunity. In particular, the technique of membrane-coating has demonstrated remarkable improvements to therapeutic nanoparticles (NPs) in terms of tolerance and stability while also improving their biomimetic performance for immunomodulatory purposes. This development has led to the emergence of using cell-membrane-based biomimetic NPs in treating sepsis-associated immunologic derangements. In this minireview, we present an overview of the recent advances in membrane-camouflaged biomimetic NPs, highlighting their multifaceted immunomodulatory effects in sepsis such as anti-infection, vaccination, inflammation control, reversing of immunosuppression, and targeted delivery of immunomodulatory agents.

Immune-regulating camouflaged nanoplatforms: A promising strategy to improve cancer nano-immunotherapy

Although nano-immunotherapy has advanced dramatically in recent times, there remain two significant hurdles related to immune systems in cancer treatment, such as (namely) inevitable immune elimination of nanoplatforms and severely immunosuppressive microenvironment with low immunogenicity, hampering the performance of nanomedicines. To address these issues, several immune-regulating camouflaged nanocomposites have emerged as prevailing strategies due to their unique characteristics and specific functionalities. In this review, we emphasize the composition, performances, and mechanisms of various immune-regulating camouflaged nanoplatforms, including polymer-coated, cell membrane-camouflaged, and exosome-based nanoplatforms to evade the immune clearance of nanoplatforms or upregulate the immune function against the tumor. Further, we discuss the applications of these immune-regulating camouflaged nanoplatforms in directly boosting cancer immunotherapy and some immunogenic cell death-inducing immunotherapeutic modalities, such as chemotherapy, photothermal therapy, and reactive oxygen species-mediated immunotherapies, highlighting the current progress and recent advancements. Finally, we conclude the article with interesting perspectives, suggesting future tendencies of these innovative camouflaged constructs towards their translation pipeline.

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Various immune-regulating camouflaged nanoplatforms are emphasized.

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Immunotherapeutic applications of camouflaged nanoplatforms are systematically summarized.

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ICD-induced therapeutic modalities based on these nanoplatforms are discussed.

Cytokine nanosponges suppressing overactive macrophages and dampening systematic cytokine storm for the treatment of hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a highly fatal condition with the positive feedback loop between continued immune cell activation and cytokine storm as the core mechanism to mediate multiple organ dysfunction. Inspired by macrophage membranes harbor the receptors with special high affinity for proinflammation cytokines, lipopolysaccharide (LPS)-stimulated macrophage membrane-coated nanoparticles (LMNP) were developed to show strong sponge ability to both IFN-γ and IL-6 and suppressed overactivation of macrophages by inhibiting JAK/STAT signaling pathway both in vitro and in vivo. Besides, LMNP also efficiently alleviated HLH-related symptoms including cytopenia, hepatosplenomegaly and hepatorenal dysfunction and save the life of mouse models. Furthermore, its sponge effect also worked well for five human HLH samples in vitro. Altogether, it's firstly demonstrated that biocompatible LMNP could dampen HLH with high potential for clinical transformation, which also provided alternative insights for the treatment of other cytokine storm-mediated pathologic conditions such as COVID-19 infection and cytokine releasing syndrome during CAR-T therapy.

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LMNP functioned better as a multiple-cytokine sponging tool when compared with conventional macrophage coated nanoparticles.

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LMNP sponged inflammation cytokines and suppressed macrophage overactivation by inhibiting JAK/STAT signaling pathway.

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LMNP calmed down systematic cytokine storm and dampened HLH in HLH mice models.

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LMNP also worked well in sponging cytokines in human HLH samples which indicated high potential of clinical transformation.

Sponge-like nano-system suppresses tumor recurrence and metastasis by restraining myeloid-derived suppressor cells-mediated immunosuppression and formation of pre-metastatic niche

Tumor recurrence and metastasis still greatly limit the therapeutic efficiency on the majority of postoperative clinical cases. With the aim to realize more powerful treatment outcomes on postoperative malignant tumors, a sponge-like neutrophil membrane-coated nano-system (NM/PPcDG/D) was fabricated to inhibit tumor recurrence and metastasis by inhibiting the recruitment and functions of myeloid-derived suppressor cell (MDSCs), which reinforced anti-tumor immunity and also suppressed pulmonary metastasis by inhibiting the formation of pre-metastatic niche (PMN). Firstly, PPcDG/D nanoparticles (NPs) were formulated by the self-assembling and crosslinking of synthesized redox-responsive polymer (PPDG) with doxorubicin (DOX) loading in the nanocore (PPcDG/D), followed by coating with activated neutrophils membrane to fabricate biomimetic NM/PPcDG/D. The sponge-like NM/PPcDG/D not only showed obvious natural tropism to postoperative inflammatory site, but also inhibited the recruitment and functions of MDSCs, thus relieved MDSCs-mediated immunosuppression. Additionally, NM/PPcDG/D also suppressed the formation of PMN to inhibit pulmonary metastasis by reducing the recruitment of MDSCs, decreasing the permeability of pulmonary vessels and inhibiting the implantation of circulating tumor cell (CTCs). Eventually, this fabricated NM/PPcDG/D NPs significantly inhibited tumor recurrence and metastasis on postoperative triple negative breast cancer (TNBC) model, presenting a promising therapeutic strategy on postoperative malignant tumors. STATEMENT OF SIGNIFICANCE: Myeloid-derived suppressor cells (MDSCs) play important roles in accelerating tumor recurrence and metastasis by promoting the establishment of immunosuppression in postoperative inflammatory regions and facilitating the formation of pulmonary pre-metastasis niche (PMN). In order to achieve enhanced suppression of recurrence and metastasis, a sponge-like NM/PPcDG/D nano-system was designed and fabricated. This nano-system is also the first attempt to integrate the regulation effects of a nano-sponge and anti-inflammatory agent to achieve enhanced multi-mode manipulation of MDSCs. Ultimately, NM/PPcDG/D powerfully restrained the recurrence and spontaneous metastasis on TNBC model. This article also revealed the particular roles of MDSCs involved in the regulation networks of postoperative recurrence and metastasis, immunosuppression and inflammation.

Enzyme-Triggered Size-Switchable Nanosystem for Deep Tumor Penetration and Hydrogen Therapy

The poor penetration of nanocarriers within tumor dense extracellular matrices (ECM) greatly restricts the access of anticancer drugs to the deep tumor cells, resulting in low therapeutic efficacy. Moreover, the high toxicity of the traditional chemotherapeutics inevitably causes undesirable side effects. Herein, taking the advantages of biosafe H₂ and small-sized nanoparticles in diffusion within tumor ECM, we develop a matrix metalloprotease 2 (MMP-2) responsive size-switchable nanoparticle (UAMSN@Gel-PEG) that is composed of ultrasmall amino-modified mesoporous silica nanoparticles (UAMSN) wrapped within a PEG-conjugated gelatin to deliver H₂ to the deep part of tumors for effective gas therapy. Ammonia borane (AB) is chosen as the H₂ prodrug that can be effectively loaded into UAMSN by hydrogen-bonding adsorption. Gelatin is used as the substrate of MMP-2 to trigger size change and block AB inside UAMSN during blood circulation. PEG is introduced to further increase the particle size and endow the nanoparticle with long blood circulation to achieve effective tumor accumulation via the EPR effect. After accumulation into the tumor site, MMP-2 promptly digests gelatin to expose UAMSN loading AB for deep tumor penetration. Upon stimulation by the acidic tumor microenvironment, AB decomposes into H₂ for further intratumor diffusion to achieve effective hydrogen therapy. Consequently, such a simultaneous deep tumor penetration of nanocarriers and H₂ results in an evident suppression on tumor growth in a 4T1 tumor-bearing model without any obvious toxicity on normal tissues. Our synthetic nanosystem provides a promising strategy for the development of nanomedicines with enhanced tumor permeability and good biosafety for efficient tumor treatment.

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.

Imaging-Guided Biomimetic M1 Macrophage Membrane-Camouflaged Magnetic Nanorobots for Photothermal Immunotargeting Cancer Therapy

Biohybrid micro/nanorobots have demonstrated improved therapeutic outcomes for targeting and treating diseases in preclinical trials. However, in vivo applications remain challenging due to a lack of sufficient targeting. Based on evidence that immune cells play a role in the immune modulation in the tumor microenvironment, we developed M1 macrophage membrane-coated magnetic photothermal nanocomplexes (MPN) for photoacoustic (PA) imaging-guided tumor therapy. The MPN were able to inherit the protein from the original macrophage cells and exert a targeted immunosuppression role. Integrating black phosphorus quantum dots and DOX also greatly enhanced reactive oxygen species generation and chemo-phototherapy efficacy. The results suggest that the MPN can be employed as an excellent tumor immunotargeting nanorobotic platform for modulating the tumor microenvironment under PA imaging and magnetic guidance and, thus, exert synergistic therapeutic efficacies.

Macrophage cell membrane-based nanoparticles: a new promising biomimetic platform for targeted delivery and treatment

Synthetic nanoparticles with surface bioconjugation are promising platforms for targeted therapy, but their simple biological functionalization is still a challenging task against the complex intercellular environment. Once synthetic nanoparticles enter the body, they are phagocytosed by immune cells by the immune system. Recently, the cell membrane camouflage strategy has emerged as a novel therapeutic tactic to overcome these issues by utilizing the fundamental properties of natural cells. Macrophage, a type of immune system cells, plays critical roles in various diseases, including cancer, atherosclerosis, rheumatoid arthritis, infection and inflammation, due to the recognition and engulfment function of removing substances and pathogens. Macrophage membranes inherit the surface protein profiles and biointerfacing properties of source cells. Therefore, the macrophage membrane cloaking can protect synthetic nanoparticles from phagocytosis by the immune cells. Meanwhile, the macrophage membrane can make use of the natural correspondence to accurately recognize antigens and target inflamed tissue or tumor sites. In this review, we have summarized the advances in the fabrication, characterization and homing capacity of macrophage membrane cloaking nanoparticles in various diseases, including cancers, immune diseases, cardiovascular diseases, central nervous system diseases, and microbial infections. Although macrophage membrane-camouflaged nanoparticles are currently in the fetal stage of development, there is huge potential and challenge to explore the conversion mode in the clinic.

Targeting inorganic nanoparticles to tumors using biological membrane-coated technology

Inorganic nanoparticles have extensively revolutionized the effectiveness of cancer therapeutics due to their distinct physicochemical properties. However, the therapeutic efficiency of inorganic nanoparticles is greatly hampered by the complex tumor microenvironment, patient heterogeneity, and systemic nonspecific toxicity. The biomimetic technology based on biological membranes (cell- or bacteria-derived membranes) is a promising strategy to confer unique characteristics to inorganic nanoparticles, such as superior biocompatibility, prolonged circulation time, immunogenicity, homologous tumor targeting, and flexible engineering approaches on the surface, resulting in the enhanced therapeutic efficacy of inorganic nanoparticles against cancer. Therefore, a greater push toward developing biomimetic-based nanotechnology could increase the specificity and potency of inorganic nanoparticles for effective cancer treatment. In this review, we summarize the recent advances in biological membrane-coated inorganic nanoparticles in cancer precise therapy and highlight the different types of engineered approaches, applications, mechanisms, and future perspectives. The surface engineering of biological membrane can greatly enhance their targeting, intelligence, and functionality, thereby realizing stronger tumor therapy effects. Further advances in materials science, biomedicine, and oncology can facilitate the clinical translation of biological membrane-coated inorganic nanoparticles.

Cell membrane-camouflaged PLGA biomimetic system for diverse biomedical application

The emerging cell membrane (CM)-camouflaged poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs) (CM@PLGA NPs) have witnessed tremendous developments since coming to the limelight. Donning a novel membrane coat on traditional PLGA carriers enables combining the strengths of PLGA with cell-like behavior, including inherently interacting with the surrounding environment. Thereby, the in vivo defects of PLGA (such as drug leakage and poor specific distribution) can be overcome, its therapeutic potential can be amplified, and additional novel functions beyond drug delivery can be conferred. To elucidate the development and promote the clinical transformation of CM@PLGA NPs, the commonly used anucleate and eukaryotic CMs have been described first. Then, CM engineering strategies, such as genetic and nongenetic engineering methods and hybrid membrane technology, have been discussed. The reviewed CM engineering technologies are expected to enrich the functions of CM@PLGA for diverse therapeutic purposes. Third, this article highlights the therapeutic and diagnostic applications and action mechanisms of PLGA biomimetic systems for cancer, cardiovascular diseases, virus infection, and eye diseases. Finally, future expectations and challenges are spotlighted in the concept of translational medicine.

Targeted nanomedicines remodeling immunosuppressive tumor microenvironment for enhanced cancer immunotherapy

Cancer immunotherapy has significantly flourished and revolutionized the limited conventional tumor therapies, on account of its good safety and long-term memory ability. Discouragingly, low patient response rates and potential immune-related side effects make it rather challenging to literally bring immunotherapy from bench to bedside. However, it has become evident that, although the immunosuppressive tumor microenvironment (TME) plays a pivotal role in facilitating tumor progression and metastasis, it also provides various potential targets for remodeling the immunosuppressive TME, which can consequently bolster the effectiveness of antitumor response and tumor suppression. Additionally, the particular characteristics of TME, in turn, can be exploited as avenues for designing diverse precise targeting nanomedicines. In general, it is of urgent necessity to deliver nanomedicines for remodeling the immunosuppressive TME, thus improving the therapeutic outcomes and clinical translation prospects of immunotherapy. Herein, we will illustrate several formation mechanisms of immunosuppressive TME. More importantly, a variety of strategies concerning remodeling immunosuppressive TME and strengthening patients' immune systems, will be reviewed. Ultimately, we will discuss the existing obstacles and future perspectives in the development of antitumor immunotherapy. Hopefully, the thriving bloom of immunotherapy will bring vibrancy to further exploration of comprehensive cancer treatment.

Metal-phenolic networks with ferroptosis to deliver NIR-responsive CO for synergistic therapy

As an endogenous gasotransmitter, CO has achieved tremendous advances in cancer treatment through selectively killing cancer cells. However, the application of CO in tumor immunotherapy has not been reported and the tumor targeting delivery is still a tremendous challenge. Herein, thermosensitive boronic acid group-containing CO prodrug was synthesized and fabricated with tannic acid (TA) and iron (Fe) to form metal-phenolic networks, and then loaded with near-infrared (NIR) photothermal agent IR820 to form FeCO-IR820@Fe^IIITA for combinational therapy of CO and photothermal therapy. Ferroptosis can also be enhanced due to the Fe³⁺ incorporation. After TA reduced Fe³⁺ into Fe²⁺, Fe²⁺ might lead to intracellular Fenton reaction. Furthermore, in combination with CTLA-4 blockade immunotherapy, FeCO-IR820@Fe^IIITA remarkably inhibited breast tumor growth, suppressed the lung metastasis and improved the antitumor immune response. To summarize, FeCO-IR820@Fe^IIITA provides a potential novel option for CO/photothermal/immune synergistic therapy with enhanced ferroptosis through simple compositions and facile synthesis process.

Penetrating Macrophage-Based Nanoformulation for Periodontitis Treatment

Periodontitis is a chronic inflammatory disease caused by the interaction of oral microorganisms with the host immune response. Porphyromonas gingivalis (P.g.) acts as a key mediator in subverting the homeostasis of the local immune system. On the one hand, P.g. inhibits phagocytosis and the killing capacity of immune cells. On the other hand, P.g. increases selective cytokine release, which is beneficial to its further proliferation. Here, we prepared a penetrating macrophage-based nanoformulation (MZ@PNM)-encapsulating hydrogel (MZ@PNM@GCP) that responded to the periodontitis microenvironment. MZ@PNM targeted P.g. via the Toll-like receptor complex 2/1 (TLR2/1) on its macrophage-mimicking membrane, then directly killed P.g. through disruption of bacterial structural integrity by the cationic nanoparticles and intracellular release of an antibacterial drug, metronidazole (MZ). Meanwhile, MZ@PNM interrupted the specific binding of P.g. to immune cells and neutralized complement component 5a (C5a), preventing P.g. subversion of periodontal host immune response. Overall, MZ@PNM@GCP showed potent efficacy in periodontitis treatment, restoring local immune function and killing pathogenic bacteria, while exhibiting favorable biocompatibility, all of which have been demonstrated both in vivo and in vitro.

Oxygen-boosted biomimetic nanoplatform for synergetic phototherapy/ferroptosis activation and reversal of immune-suppressed tumor microenvironment

Photodynamic therapy (PDT) induces apoptosis of cancer cells by generating cytotoxic reactive oxygen species, the therapeutic effect of which, however, is impeded by intrinsic/inducible apoptosis-resistant mechanisms in cancer cells and hypoxia of tumor microenvironment (TME); also, PDT-induced anti-tumor immunity activation is insufficient. To deal with these obstacles, a novel biomimetic nanoplatform is fabricated for the precise delivery of photosensitizer chlorin e6 (Ce6), hemin and PEP20 (CD47 inhibitory peptide), integrating oxygen-boosted PDT, ferroptosis activation and CD47-SIRPα blockade. Hemin's catalase-mimetic activity alleviates TME hypoxia and enhances PDT. The nanoplatform activates ferroptosis via both classical (down-regulating glutathione peroxidase 4 pathway) and non-classical (inducing Fe²⁺ overload) modes. Besides the role of hemin in consuming glutathione and up-regulating heme oxygenase-1 expression, interestingly, we observe that Ce6 enhance ferroptosis activation via both classical and non-classical modes. The anti-cancer immunity is reinforced by combining PEP20-mediated CD47-SIRPα blockade and PDT-mediated T cell activation, efficiently suppressing primary tumor growth and metastasis. PEP20 has been revealed for the first time to sensitize ferroptosis by down-regulating system Xc^-. This work sheds new light on the mechanisms of PDT-ferroptosis activation interplay and bridges immunotherapy and ferroptosis activation, laying the theoretical foundation for novel combinational modes of cancer treatment.

Recent advances in biological membrane-based nanomaterials for cancer therapy

Nanomaterials have shown significant advantages in cancer theranostics, owing to their enhanced permeability and retention effect in tumors and multi-function integration capability. Biological membranes, which are collected from various cells and their secreted membrane structures, can further be applied to establish membrane-based nanomaterials with perfect biocompatibility, tumor-targeting capacity, immune-stimulatory activity and adjustable versatility for cancer therapy. In this review, according to their source, membranes are divided into four groups: (1) cell membranes; (2) secretory membranes; (3) engineered membranes; and (4) hybrid membranes. First, cell membranes can be extracted from natural cells of the body, tumor tissue cells, and bacteria. Furthermore, secretory membranes mainly refer to exosome, apoptotic body and bacterial outer membrane vesicle, and membranes with specific protein/peptide expression or therapeutic inclusions are obtained from engineered cells. Finally, a hybrid membrane will be constituted by two or more of the abovementioned membranes. These membranes can form drug-carrying nanoparticles themselves or coat multi-functional nanoparticles, further realizing efficient cancer therapy. We summarize the application of various biological membrane-based nanomaterials in cancer therapy and point out their advantages as well as the places that need to be further improved, providing systematic knowledge of this field and a strategy for further optimization.

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.