Cell Membrane Coating Technology: A Promising Strategy for Biomedical Applications

Ultradense Erythrocyte Bionic Layer Used to Capture Circulating Tumor Cells and Plasma-Assisted High-Purity Release

The isolation and detection of rare circulating tumor cells (CTCs) from patient peripheral blood can help early diagnosis of cancer and evaluation of therapeutic outcomes. At present, most of the available strategies for enriching CTCs face serious problems with purity due to the nonspecific interactions between the capture medium and leukocytes. Inspired by the immune evasion ability of homologous red blood cells (RBCs), we modified the tumor-targeting molecule folic acid (FA) on the surface of RBCs by hydrophobic interactions. Under the treatment of polybrene, the charges on the surface of RBCs are neutralized, which reduces the mutual repulsion force. Furthermore, RBCs treated with polyethylene also have excellent deformability, thereby enabling engineered RBCs to form a dense bionic layer on the adhesive glass slide, which can greatly inhibit the nonspecific adhesion of leukocytes. The bionic layer can achieve high-purity enrichment of tumor cells in phosphate-buffered saline (PBS), and we can achieve high-activity release in plasma. The cell count showed over 80% capture efficiency and over 70% release rate, and the purity of CTCs obtained in the artificial blood sample after release was higher than 90%. The RBC bionic surface coating is notably cost-effective and highly applicable for CTC isolation in clinic practice, and thus provides new prospects for designing cell-material interfaces for advanced cell-based biomedical studies in the future.

New advances in brain-targeting nano-drug delivery systems for Alzheimer's disease

Alzheimer's disease (AD) is the most common neurodegenerative disease worldwide and its incidence is increasing due to the ageing population. Currently, the main limitations of AD treatment are low blood-brain barrier permeability, severe off-target of drugs, and immune abnormality. In this review, four hypotheses for Alzheimer's pathogenesis and three challenges for Alzheimer's drug delivery are discussed. In addition, this article summarises the different strategies of brain targeting nano-drug delivery systems (NDDSs) developed in the last 10 years. These strategies include receptor-mediated (transferrin receptor, low-density lipoprotein receptor-related protein, lactoferrin receptor, etc.), adsorption-mediated (cationic, alkaline polypeptide, cell-penetrating peptides, etc.), and transporter-mediated (P-gp, GLUT1, etc.). Moreover, it provides insights into novel strategies used in AD, such as exosomes, virus-like particles, and cell membrane coating particles. Hence, this review will help researchers to understand the current progress in the field of NDDSs for the central nervous system and find new directions for AD therapy.HighlightsCharacteristics and challenges based on the pathogenesis of AD were discussed.Recent advances in novel brain-targeting NDDSs for AD over the past 10 years were summarised.

Orchestration of biomimetic membrane coating and nanotherapeutics in personalized anticancer therapy

Nanoparticle-based therapeutic and detectable modalities can augment anticancer efficiency, holding potential in capable target and suppressive metastases post administration. However, the individual discrepancies of the current "one-size-fits-all" strategies for anticancer nanotherapeutics have heralded the need for "personalized therapy". Benefiting from the special inherency of various cells, diverse cell membrane-coated nanoparticles (CMCNs) were established on a patient-by-patient basis, which would facilitate the personalized treatment of individual cancer patients. CMCNs in a complex microenvironment can evade the immune system and target homologous tumors with a suppressed immune response, as well as a prolonged circulation time, consequently increasing the drug accumulation at the tumor site and anticancer therapeutic efficacy. This review focuses on the emerging strategies and advances of CMCNs to synergistically integrate the merit of source cells with nanoparticulate delivery systems for the orchestration of personalized anticancer nanotherapeutics, thus discussing their rationalities in facilitating chemotherapy, imaging, immunotherapy, phototherapy, radiotherapy, sonodynamic, magnetocaloric, chemodynamic and gene therapy. Furthermore, the mechanism, challenges and opportunities of CMCNs in personalized anticancer therapy were highlighted to further boost cooperation from different fields, including materials science, chemistry, medicine, pharmacy and biology for the lab-to-clinic translation of CMCNs combined with the individual advantages of source cells and nanotherapeutics.

Advances in nano-biomaterials and their applications in biomedicine

Nanotechnology has received considerable attention and interest over the past few decades in the field of biomedicine due to the wide range of applications it provides in disease diagnosis, drug design and delivery, biomolecules detection, tissue engineering and regenerative medicine. Ultra-small size and large surface area of nanomaterials prove to be greatly advantageous for their biomedical applications. Moreover, the physico-chemical and thus, the biological properties of nanomaterials can be manipulated depending on the application. However, stability, efficacy and toxicity of nanoparticles remain challenge for researchers working in this area. This mini-review highlights the recent advances of various types of nanoparticles in biomedicine and will be of great value to researchers in the field of materials science, chemistry, biology and medicine.

Interactions between Biomedical Micro-/Nano-Motors and the Immune Molecules, Immune Cells, and the Immune System: Challenges and Opportunities

Mobile micro- and nano-motors (MNMs) emerge as revolutionary platforms for biomedical applications, including drug delivery, biosensing, non-invasive surgery, and cancer therapy. While for applications in biomedical fields and practical clinical translation, the interactions of these untethered tiny machines with the immune system is an essential issue to be considered. This review highlights the recent approaches of surpassing immune barriers to prevent foreign motors from triggering immune responses. In addition to trials focusing on the function preservation of MNMs, examples of versatile MNMs working with the immune components (immune molecules, immune cells and the whole system) to achieve cancer immunotherapy, immunoassay, and detoxification are outlined. The immune interference part provides researchers an idea about what is the limit presented by the immune components. The coworking part suggests ways to bypass or even utilize the limit. With interdisciplinary cooperation of nanoengineering, materials science, and immunology field, the rationally designed functional MNMs are expected to provide novel opportunities for the biomedical field.

Immune Cell Membrane-Coated Biomimetic Nanoparticles for Targeted Cancer Therapy

Nanotechnology has provided great opportunities for managing neoplastic conditions at various levels, from preventive and diagnostic to therapeutic fields. However, when it comes to clinical application, nanoparticles (NPs) have some limitations in terms of biological stability, poor targeting, and rapid clearance from the body. Therefore, biomimetic approaches, utilizing immune cell membranes, are proposed to solve these issues. For example, macrophage or neutrophil cell membrane coated NPs are developed with the ability to interact with tumor tissue to suppress cancer progression and metastasis. The functionality of these particles largely depends on the surface proteins of the immune cells and their preserved function during membrane extraction and coating process on the NPs. Proteins on the outer surface of immune cells can render a wide range of activities to the NPs, including prolonged blood circulation, remarkable competency in recognizing antigens for enhanced targeting, better cellular interactions, gradual drug release, and reduced toxicity in vivo. In this review, nano-based systems coated with immune cells-derived membranous layers, their detailed production process, and the applicability of these biomimetic systems in cancer treatment are discussed. In addition, future perspectives and challenges for their clinical translation are also presented.

Advances on erythrocyte-mimicking nanovehicles to overcome barriers in biological microenvironments

Although nanocarriers offer many advantages as drug delivery systems, their poor stability in circulation, premature drug release and nonspecific uptake in non-target organs have prompted biomimetic approaches using natural cell membranes to camouflage nanovehicles. Among them, erythrocytes, representing the most abundant blood circulating cells, have been extensively investigated for biomimetic coating on artificial nanocarriers due to their upgraded biocompatibility, biodegradability, non-immunogenicity and long-term blood circulation. Due to the cell surface mimetic properties combined with customized core material, erythrocyte-mimicking nanovehicles (EM-NVs) have a wide variety of applications, including drug delivery, imaging, phototherapy, immunomodulation, sensing and detection, that foresee a huge potential for therapeutic and diagnostic applications in several diseases. In this review, we summarize the recent advances in the biomedical applications of EM-NVs in cancer, infection, heart-, autoimmune- and CNS-related disorders and discuss the major challenges and opportunities in this research area.

Cancer-associated-platelet-inspired nanomedicines for cancer therapy

Platelets, with hemostasis and thrombosis activities, are one of the key components in the blood circulation. As a guard, they rapidly respond to any abnormal blood vessel injury signal and release their granules' contents, which induce their adhesion and aggregation on wound site for hemostasis. Recently, increasing evidence has indicated that platelets are critically involved in the growth and metastasis of cancer cells by releasing a variety of cytokines and chemokines to stimulate cancer cell proliferation and various angiogenic regulators to accelerate tumor angiogenesis. Platelets also secrete active transforming growth factor beta (TGF-β) to promote the epithelial-mesenchymal transition of cancer cells and their extravasation from primary site, and form microthrombus on the surface of cancer cells to protect them from immune attack and high-speed shear force in the circulation. Therefore, blocking platelet-cancer cell interaction may be an attractive strategy to treat primary tumor and/or prevent cancer metastasis. However, systemic inhibition or depletion of platelets brings risk of severe bleeding complication. Cancer-associated-platelets-targeted nanomedicines and biomimetic nanomedicines coated with platelet membrane can be used for targeted anticancer drug delivery, due to their natural targeting ability to tumor cells and platelets. In the current review, we first summarized the platelet mechanisms of action in physiological condition and their multiple roles in cancer progression and conventional antiplatelet therapeutics. We then highlighted the recent progress on the design and fabrication of cancer-associated-platelet-targeted nanomedicines and platelet membrane coating nanomedicines for cancer therapy. Finally, we discussed opportunities and challenges and offered our thoughts for the future development. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Biology-Inspired Nanomaterials > Lipid-Based Structures.

Versatile Nanoscale Metal-Organic Frameworks (nMOFs): An Emerging 3D Nanoplatform for Drug Delivery and Therapeutic Applications

For decades, nanoscale metal-organic frameworks (nMOFs) have attracted extensive interest in biomedicine due to their distinct characteristics, including facile synthesis, porous interior, and tunable biocompatibility. With high porosity, versatile nMOFs allow for the facile encapsulation of various therapeutic agents with exceptionally high payloads. Constructed from metal ions and organic linkers through coordination bonds, nMOFs with plentiful functional groups enable the surface modification for active targeting and enhanced biocompatibility. This review outlines the up-to-date progresses on the exploration of nMOFs in the field of biomedicine. First, the classification and synthesis of nMOFs are discussed, followed by the concrete introduction of drug loading strategies of nMOFs and mechanisms of stimulation-responsive drug release. Second, the smart designs of the nMOFs-based platforms for anticancer and antibacterial treatment are summarized. Finally, the basic challenges faced by nMOFs research and the great potential of biomimetic nMOFs are presented. This review article affords an inspiring insight into the interdisciplinary research of nMOFs and their biomedical applications, which holds great expectation for their further clinical translation.

Designing and Immunomodulating Multiresponsive Nanomaterial for Cancer Theranostics

Cancer has been widely investigated yet limited in its manifestation. Cancer treatment holds innovative and futuristic strategies considering high disease heterogeneity. Chemotherapy, radiotherapy and surgery are the most explored pillars; however optimal therapeutic window and patient compliance recruit constraints. Recently evolved immunotherapy demonstrates a vital role of the host immune system to prevent metastasis recurrence, still undesirable clinical response and autoimmune adverse effects remain unresolved. Overcoming these challenges, tunable biomaterials could effectively control the co-delivery of anticancer drugs and immunomodulators. Current status demands a potentially new approach for minimally invasive, synergistic, and combinatorial nano-biomaterial assisted targeted immune-based treatment including therapeutics, diagnosis and imaging. This review discusses the latest findings of engineering biomaterial with immunomodulating properties and implementing novel developments in designing versatile nanosystems for cancer theranostics. We explore the functionalization of nanoparticle for delivering antitumor therapeutic and diagnostic agents promoting immune response. Through understanding the efficacy of delivery system, we have enlightened the applicability of nanomaterials as immunomodulatory nanomedicine further advancing to preclinical and clinical trials. Future and present ongoing improvements in engineering biomaterial could result in generating better insight to deal with cancer through easily accessible immunological interventions.

Cell primitive-based biomimetic functional materials for enhanced cancer therapy

Cell primitive-based functional materials that combine the advantages of natural substances and nanotechnology have emerged as attractive therapeutic agents for cancer therapy. Cell primitives are characterized by distinctive biological functions, such as long-term circulation, tumor specific targeting, immune modulation etc. Moreover, synthetic nanomaterials featuring unique physical/chemical properties have been widely used as effective drug delivery vehicles or anticancer agents to treat cancer. The combination of these two kinds of materials will catalyze the generation of innovative biomaterials with multiple functions, high biocompatibility and negligible immunogenicity for precise cancer therapy. In this review, we summarize the most recent advances in the development of cell primitive-based functional materials for cancer therapy. Different cell primitives, including bacteria, phages, cells, cell membranes, and other bioactive substances are introduced with their unique bioactive functions, and strategies in combining with synthetic materials, especially nanoparticulate systems, for the construction of function-enhanced biomaterials are also summarized. Furthermore, foreseeable challenges and future perspectives are also included for the future research direction in this field.

Recent advances in cell membrane coated metal-organic frameworks (MOFs) for tumor therapy

In improving the tumor-targeting ability of metal-organic frameworks (MOFs) for tumor therapy and avoiding the clearance as well as capture by the immune system, there are still several challenges, which limit the development and bio-applications of MOFs. To overcome these challenges, various targeted modification strategies have been proposed. Amongst all the strategies, a promising cell membrane coating method has been explored and utilized for the syntheses of new cell membrane biomimetic MOFs (CMMs). Through such coating, various source cell membranes (e.g., red blood cell, immune cell, cancer cell, platelet, and fusion cell membranes) can be endowed with excellent properties such as long blood circulation, immune escape, and targeting ability. In the presented perspective, the synthetic method, characterization, and research progress in tumor therapy based on CMMs have been summarized. This is because, like many other technologies, the cell membrane coating technology also has several challenges to overcome. Hence, addressing and overcoming such challenges will promote and extend the bio-applications of MOFs which in the future may become a prospective carrier for cancer nano-medicine. Finally, the prospects and challenges of utilizing CMMs for tumor therapy have been discussed.

Active-Targeting NIR-II Phototheranostics in Multiple Tumor Models Using Platelet-Camouflaged Nanoprobes

Cancer phototheranostics in the second near-infrared window (NIR-II, 1000-1700 nm) has recently attracted much attention owing to its high efficacy and good safety compared with that in the first near-infrared window (NIR-I, 650-950 nm). However, the lack of theranostic nanoagents with active-targeting features limits its further application in cancer precision therapies. Herein, we constructed platelet-camouflaged nanoprobes with active-targeting characteristics for NIR-II cancer phototheranostics. The as-prepared biomimetic nanoprobes can not only escape phagocytosis by macrophages but also specifically bind to CD44 on the surface of most cancer cells. We evaluated the active-targeting performance of biomimetic nanoprobes in pancreatic cancer, breast cancer, and glioma mouse models and achieved NIR-II photoacoustic imaging with a high signal-to-background ratio and photothermal treatment with excellent tumor growth inhibition. Our results show the great potential of platelet-camouflaged nanoprobes with NIR-II active-targeting features for cancer precision diagnosis and efficient therapies.

Cell membrane-encapsulated magnetic nanoparticles for enhancing natural killer cell-mediated cancer immunotherapy

Natural killer (NK) cells have exhibited therapeutic potential for various malignant tumors. However, the cytotoxic effect of NK cells is relatively weak and less specific compared to other immunotherapy approaches such as chimeric antigen receptor T-Cell (CART) therapy, constituting a great challenge for adoptive immunotherapy. Here, we report cell membrane-encapsulated magnetic nanoparticles for activating NK cells and enhancing anti-tumor effects. Magnetic nanoparticles were coated with silicon dioxide (SiO₂), and cancer cell membranes were mixed with Fe₃O₄@SiO₂ to construct cancer cell membrane coated Fe₃O₄@SiO₂ magnetic nanoparticles (CMNPs). The functionalized nanoparticles bearing cancer-specific antigens on the surface effectively stimulated NK cells by enhancing expression of surface activating receptors and boosting anti-tumor function through the secretion of soluble cytotoxic effectors. To conclude, the biomimetic magnetic nanoparticles offer a versatile and powerful tool to present tumor-specific antigens, priming anti-tumor capability, which is promising to enhance NK cell-based adoptive cancer immunotherapy.

Cyclosporine CsA—The Physicochemical Characterization of Liposomal and Colloidal Systems

This paper presents an overview of the possibilities of testing various cyclosporine (CsA) formulations with an emphasis on parameters that may be key to improving the stability and biocompatibility. The feasibility of CsA colloidal systems for oral (injection) administration were investigated using different techniques and compared with similar investigations of other researchers. The chosen CsA systems were developed using dipalmitoylphosphocholine (DPPC) and/or cholesterol as a lipid matrix, stabilized with ethanol, with soybean oil or n-tetradecane as oil phase in emulsions, under natural pH, room and physiological temperature. Their integrity was found to be strictly dependent on the stabilizers. The highest CsA penetrability with the system containing phospholipid in the context of its interactions with lipid membranes was shown. Also, the bioavailability of CsA can be enhanced with the biopolymer antibacterial chitosan. This mini-review suggests the suitability of liposome/microemulsion as promising vehicles for CsA delivery. The most hopeful proved to be formulation with the smaller particle size facilitating absorption, but when safety is assessed, relying on just the particle size cannot be the only criteria. Reassumed, the CsA formulation stability known on the basis of the size and zeta potential measurements guarantees a decrease of the individual variations in the drug bioavailability, toxicity and minimizes rejection.

Construction of biomimetic silver nanoparticles in the treatment of lymphoma

Lymphoma is a well-known malignant tumor in the human body. Although many anticancer drugs have been developed to improve the survival rate of patients, about 40% of patients continue to be recurrent or refractory, a key issue needing remedy. Therefore, it is necessary to identify alternative treatments to reduce the disease's mortality. To this effect, a new type of anti-lymphoma nanocomplex FA@RBCm-AgNPs was prepared using AgNPs as the core of nanoparticles along with the targeting molecule folic acid inserted erythrocyte membrane as the shell. The biomimetic properties of red blood cell membrane (RBCm) endow F-RAN with good biocompatibility as well as the ability to evade clearance of the reticuloendothelial system. In addition, F-RAN was modified with folic acid to actively and selectively identify tumor cells. In vivo and in vitro experiments demonstrate that F-RAN can inhibit lymphoma cells and induce apoptosis of stem cells while promoting apoptosis of lymphoma with no obvious side effects. Hence, F-RAN may serve as a new treatment for lymphoma.

Neuroinflammation Treatment via Targeted Delivery of Nanoparticles

The lack of effective treatments for most neurological diseases has prompted the search for novel therapeutic options. Interestingly, neuroinflammation is emerging as a common feature to target in most CNS pathologies. Recent studies suggest that targeted delivery of small molecules to reduce neuroinflammation can be beneficial. However, suboptimal drug delivery to the CNS is a major barrier to modulate inflammation because neurotherapeutic compounds are currently being delivered systemically without spatial or temporal control. Emerging nanomaterial technologies are providing promising and superior tools to effectively access neuropathological tissue in a controlled manner. Here we highlight recent advances in nanomaterial technologies for drug delivery to the CNS. We propose that state-of-the-art nanoparticle drug delivery platforms can significantly impact local CNS bioavailability of pharmacological compounds and treat neurological diseases.

Biomimetic Nanocarriers for Cancer Target Therapy

Nanotechnology offers innovative tools for the design of biomimetic nanocarriers for targeted cancer therapy. These nano-systems present several advantages such as cargo's protection and modulation of its release, inclusion of stimuli-responsive elements, and enhanced tumoral accumulation. All together, these nano-systems suffer low therapeutic efficacy in vivo because organisms can recognize and remove foreign nanomaterials. To overcome this important issue, different modifications on nanoparticle surfaces were exploited in order to reach the desired therapeutic efficacy eliciting, also, the response of immune system against cancer cells. For this reason, more recently, a new strategy involving cell membrane-covered nanoparticles for biomedical application has been attracting increasing attention. Membranes from red blood cells, platelets, leukocytes, tumor, and stem cells, have been exploited as biomimetic coatings of nanoparticles for evading clearance or stimulated immune system by maintaining in the same way their targeting capability. In this review, the use of different cell sources as coating of biomimetic nanocarriers for cancer therapy is discussed.

A Review on Nano-Based Drug Delivery System for Cancer Chemoimmunotherapy

Although notable progress has been made on novel cancer treatments, the overall survival rate and therapeutic effects are still unsatisfactory for cancer patients. Chemoimmunotherapy, combining chemotherapeutics and immunotherapeutic drugs, has emerged as a promising approach for cancer treatment, with the advantages of cooperating two kinds of treatment mechanism, reducing the dosage of the drug and enhancing therapeutic effect. Moreover, nano-based drug delivery system (NDDS) was applied to encapsulate chemotherapeutic agents and exhibited outstanding properties such as targeted delivery, tumor microenvironment response and site-specific release. Several nanocarriers have been approved in clinical cancer chemotherapy and showed significant improvement in therapeutic efficiency compared with traditional formulations, such as liposomes (Doxil®, Lipusu®), nanoparticles (Abraxane®) and micelles (Genexol-PM®). The applications of NDDS to chemoimmunotherapy would be a powerful strategy for future cancer treatment, which could greatly enhance the therapeutic efficacy, reduce the side effects and optimize the clinical outcomes of cancer patients. Herein, the current approaches of cancer immunotherapy and chemoimmunotherapy were discussed, and recent advances of NDDS applied for chemoimmunotherapy were further reviewed.

Cell Membrane-Based Biomimetic Nanoparticles and the Immune System: Immunomodulatory Interactions to Therapeutic Applications

Nanoparticle-based drug delivery systems have been synthesized from a wide array of materials. The therapeutic success of these platforms hinges upon their ability to favorably interact with the biological environment (both systemically and locally) and recognize the diseased target tissue. The immune system, composed of a highly coordinated organization of cells trained to recognize foreign bodies, represents a key mediator of these interactions. Although components of this system may act as a barrier to nanoparticle (NP) delivery, the immune system can also be exploited to target and trigger signaling cues that facilitate the therapeutic response stemming from systemic administration of NPs. The nano-bio interface represents the key facilitator of this communication exchange, where the surface properties of NPs govern their in vivo fate. Cell membrane-based biomimetic nanoparticles have emerged as one approach to achieve targeted drug delivery by actively engaging and communicating with the biological milieu. In this review, we will highlight the relationship between these biomimetic nanoparticles and the immune system, emphasizing the role of tuning the nano-bio interface in the immunomodulation of diseases. We will also discuss the therapeutic applications of this approach with biomimetic nanoparticles, focusing on specific diseases ranging from cancer to infectious diseases. Lastly, we will provide a critical evaluation on the current state of this field of cell membrane-based biomimetic nanoparticles and its future directions in immune-based therapy.