Effective and Targeted Human Orthotopic Glioblastoma Xenograft Therapy via a Multifunctional Biomimetic Nanomedicine

Recent advances in biomimetic nanodelivery systems for the treatment of glioblastoma

Glioblastoma remain one of the deadliest malignant tumors in the central nervous system, largely due to their aggressiveness, high degree of heterogeneity, and the protective barrier of the blood-brain barrier (BBB). Conventional therapies including surgery, chemotherapy and radiotherapy often fail to improve patient prognosis due to limited drug penetration and non-specific toxicity. We then present recent advances in biomimetic nanodelivery systems, focusing on cell membrane coatings, nanoenzymes, and exosome-based carriers. By mimicking endogenous biological functions, these systems demonstrate improved immune evasion, enhanced BBB traversal, and selective drug release within the tumor microenvironment. Nevertheless, we acknowledge unresolved bottlenecks related to large-scale production, stability, and the intricacies of regulatory compliance. Looking forward, we propose an interdisciplinary roadmap that combines materials engineering, cellular biology, and clinical expertise. Through this collaborative approach, this work aims to optimize biomimetic nanodelivery for glioma therapy and ultimately improve patient outcomes.

Biomimetic nanocrystals co-deliver paclitaxel and small-molecule LF3 for ferroptosis-combined chemotherapy for gastric cancer

Combination chemotherapy is considered more effective than monotherapy in enhancing clinical outcomes. Ferroptosis, a unique form of regulated cell death, has been demonstrated to inhibit tumor growth and progression. Consequently, combining ferroptosis with chemotherapy represents a promising and innovative approach to antitumor therapy. In this study, we developed a novel TMTP1-modified biomimetic nanocrystal (TRNC@P + L) for the co-delivery of PTX and LF3, aiming to achieve ferroptosis-combined chemotherapy in gastric cancer. TRNC@P + L, which incorporates a tumor-homing peptide-modified red blood cell membrane, demonstrated efficient tumor targeting, prolonged circulation, enhanced drug bioavailability, and reduced non-specific toxicities of free PTX and LF3. By utilizing the synergistic effects of PTX and LF3, TRNC@P + L combination therapy significantly inhibited tumor growth, as demonstrated by both in vitro and in vivo studies. Mechanistically, TRNC@P + L triggers ferroptosis in tumor cells by downregulating GPX4 expression, the promotion of ROS accumulation, and the enhancement of lipid peroxidation. These processes synergistically enhance the anticancer efficacy of PTX.

Engineering exosome membrane disguised thermal responsive system for targeted drug delivery and controlled release across the blood-brain barrier

The blood-brain barrier (BBB) presents a significant challenge for the delivery of chemotherapy drugs to brain tumors, leading to ineffective drug concentrations at the tumor site and contributing to chemotherapy resistance. The hypoxic tumor microenvironment further complicates this process, ultimately resulting in poor patient prognosis. In this study, we developed a thermoresponsive nanocarrier system that incorporates (Ru)(Pt) bimetallic nanoparticles onto defective TiOx nanoparticles with abundant oxygen vacancies, generating composite Ru/Pt-TiOx nanoparticles with photothermal and photocatalytic properties. The Ru and Pt in the nanoparticles enhance the metal-carrier interactions, with Ru increasing both light absorption and photothermal conversion efficiency and Pt catalyzing the conversion of endogenous H2O2 in tumors to produce oxygen. The oxygen produced within the tumor microenvironment reduces HIF-1α, MDR1 and P-gp expression, thereby inhibiting efflux and allowing doxorubicin to accumulate inside the cells. DOX was incorporated into a phase change material and combined with multiple Ru/Pt-TiOx nanoparticles to form composite RPTiOx-DOX particles that can control the release of DOX under near-infrared irradiation. In an effort to overcome the blocking effect of the BBB, we wrapped the RPTiOx-DOX nanoparticles with Angiopep-2-functionalized macrophage exosome membranes. Furthermore, the changes in the internal environment promote macrophage phenotypic transformation (M2→M1) to some extent and further inhibit tumor growth via immunoregulation. In this work, a novel drug delivery system capable of traversing the BBB and exerting synergistic antitumor effects through photostimulated therapeutic agents is described, providing innovative insights for the development of stimulus-responsive composite nanoparticle drug formulations.

Nonlinear Magnetic Response Measurements in Study of Magnetic Nanoparticles Uptake by Mesenchymal Stem Cells

Stem cells therapies offer a promising approach in translational oncology, as well as in regenerative medicine due to the tropism of these cells to the damage site. To track the distribution of stem cells, the latter could be labeled by MRI-sensitive superparamagnetic (SPM) iron oxide nanoparticles. In the current study, magnetic properties of the magnetic nanoparticles (MNPs) incorporated into the bone marrow-derived fetal mesenchymal stem cells (FetMSCs) were evaluated employing nonlinear magnetic response measurements. Synthesized dextran-coated iron oxide nanoparticles were additionally characterized by X-ray diffraction, transmission electron microscopy, and dynamic light scattering. The MNP uptake by the FetMSCs 24 h following coincubation was studied by longitudinal nonlinear response to weak alternating magnetic field with registration of the second harmonic of magnetization. Subsequent data processing using a formalism based on the numerical solution of the Fokker-Planck kinetic equation allowed us to determine magnetic and dynamic parameters and the state of MNPs in the cells, as well as in the culture medium. It was found that MNPs formed aggregates in the culture medium; they were absorbed by the cells during coincubation. The aggregates exhibited SPM regime in the medium, and the parameters of the MNP aggregates remained virtually unchanged in the cells, indicating the preservation of the aggregation state of MNPs inside the cells. This implies also the preservation of the organic shell of the nanoparticles inside FetMSCs. The accumulation of MNPs by mesenchymal stem cells gradually increased with the concentration of MNPs. Thus, the study confirmed that the labeling of MSCs with MNPs is an effective method for subsequent cell tracking as incorporated nanoparticles retain their magnetic properties.

Using Regular Porous Membrane-Based Blood-Brain Barrier Model to Screen Brain-Targeted Drugs with Nanochannel Electrochemistry

Constructing in vitro blood-brain barrier (BBB) model provides an innovative approach for studying the pathophysiology of the brain and screening drugs. Although commercial Transwell was the simplest and most widely utilized in vitro model, reasonably mimicking essential characteristics of human BBB and dynamic monitoring BBB function remain a challenge. Herein, inspired by the highly permeable extracellular matrix membrane in human BBB, a novel in vitro BBB model was established by combining functionalized anodic alumina oxide (AAO) membrane with nanochannel electrochemistry (ANE-BBB). Benefiting from the topographical nanostructures and modified cell-adhesive peptide on the AAO surface, a tight endothelial barrier was formed, which can be directly visualized by phase-contrast microscope, and the barrier function can be real time monitored by nanochannel electrochemistry. More importantly, according to the current signal induced by the diffusion of redox species through the nanochannels toward the underlying electrode surface, dynamic evaluation of BBB-crossing behavior and precise screening of brain-targeted nanodrugs can be achieved. The constructed ANE-BBB overcomes the shortcomings of invisible cell culture, low permeability, and inaccurate real-time monitoring of screening drugs in traditional Transwell and provides a reliable tool for the design of nanodrugs to the central nervous system.

Biomimetic Nanoparticle Based Targeted mRNA Vaccine Delivery as a Novel Therapy for Glioblastoma Multiforme

The prognosis for patients with glioblastoma multiforme (GBM), an aggressive and deadly brain tumor, is poor due to the limited therapeutic options available. Biomimetic nanoparticles have emerged as a promising vehicle for targeted mRNA vaccine delivery, thanks to recent advances in nanotechnology. This presents a novel treatment method for GBM. This review explores the potential of using biomimetic nanoparticles to improve the specificity and effectiveness of mRNA vaccine against GBM. These nanoparticles can evade immune detection, cross the blood-brain barrier, & deliver mRNA directly to glioma cells by mimicking natural biological structures. This allows glioma cells to produce tumor-specific antigens that trigger strong immune responses against the tumor. This review discusses biomimetic nanoparticle design strategies, which are critical for optimizing transport and ensuring targeted action. These tactics include surface functionalization and encapsulation techniques. It also highlights the ongoing preclinical research and clinical trials that demonstrate the therapeutic advantages and challenges of this strategy. Biomimetic nanoparticles for mRNA vaccine delivery represent a new frontier in GBM treatment, which could impact the management of this deadly disease and improve patient outcomes by integrating cutting-edge nanotechnology with immunotherapy.

Translational nanorobotics breaking through biological membranes

In the dynamic realm of translational nanorobotics, the endeavor to develop nanorobots carrying therapeutics in rational in vivo applications necessitates a profound understanding of the biological landscape of the human body and its complexity. Within this landscape, biological membranes stand as critical barriers to the successful delivery of therapeutic cargo to the target site. Their crossing is not only a challenge for nanorobotics but also a pivotal criterion for the clinical success of therapeutic-carrying nanorobots. Nevertheless, despite their urgency, strategies for membrane crossing in translational nanorobotics remain relatively underrepresented in the scientific literature, signaling an opportunity for further research and innovation. This review focuses on nanorobots with various propulsion mechanisms from chemical and physical to hybrid mechanisms, and it identifies and describes four essential biological membranes that represent the barriers needed to be crossed in the therapeutic journey of nanorobots in in vivo applications. First is the entry point into the blood stream, which is the skin or mucosa or intravenous injection; next is the exit from the bloodstream across the endothelium to the target site; further is the entry to the cell through the plasma membrane and, finally, the escape from the lysosome, which otherwise destroys the cargo. The review also discusses design challenges inherent in translating nanorobot technologies to real-world applications and provides a critical overview of documented membrane crossings. The aim is to underscore the need for further interdisciplinary collaborations between chemists, materials scientists and chemical biologists in this vital domain of translational nanorobotics that has the potential to revolutionize the field of precision medicine.

Brain-targeting drug delivery systems: The state of the art in treatment of glioblastoma

Glioblastoma (GBM) is the most prevalent primary malignant brain tumor, characterized by a high mortality rate and a poor prognosis. The blood-brain barrier (BBB) and the blood-tumor barrier (BTB) present significant obstacles to the efficacy of tumor-targeted pharmacotherapy, thereby impeding the therapeutic potential of numerous candidate drugs. Targeting delivery of adequate doses of drug across the BBB to treat GBM has become a prominent research area in recent years. This emphasis has driven the exploration and evaluation of diverse technologies for GBM pharmacotherapy, with some already undergoing clinical trials. This review provides a thorough overview of recent advancements and challenges in targeted drug delivery for GBM treatment. It specifically emphasizes systemic drug administration strategies to assess their potential and limitations in GBM treatment. Furthermore, this review highlights promising future research directions in the development of intelligent drug delivery systems aimed at overcoming current challenges and enhancing therapeutic efficacy against GBM. These advancements not only support foundational research on targeted drug delivery systems for GBM but also offer methodological approaches for future clinical applications.

Cell Membrane Camouflaged Biomimetic Nanoparticles as a Versatile Platform for Brain Diseases Treatment

Although there are various advancements in biomedical in the past few decades, there are still challenges in the treatment of brain diseases. The main difficulties are the inability to deliver a therapeutic dose of the drug to the brain through the blood-brain barrier (BBB) and the serious side effects of the drug. Thus, it is essential to select biocompatible drug carriers and novel therapeutic tools to better enhance the effect of brain disease treatment. In recent years, biomimetic nanoparticles (BNPs) based on natural cell membranes, which have excellent biocompatibility and low immunogenicity, are widely used in the treatment of brain diseases to enable the drug to successfully cross the BBB and target brain lesions. BNPs can prolong the circulation time in vivo, are more conducive to drug aggregation in brain lesions. Cell membranes (CMs) from cancer cells (CCs), red blood cells (RBCs), white blood cells (WBCs), and so on are used as biomimetic coatings for nanoparticles (NPs) to achieve the ability to target, evade clearance, or stimulate the immune system. This review summarizes the application of different cell sources as BNPs coatings in the treatment of brain diseases and discusses the possibilities and challenges of clinical translation.

Applications of Nanomedicine in Brain Tumor Therapy: Nanocarrierbased Drug Delivery Platforms, Challenges, and Perspectives

BACKGROUND

The most difficult kind of cancer to treat is brain cancer, which causes around 3% of all cancer-related deaths. The targeted delivery is improved with the use of technologies based on nanotechnology that are both safe and efficient. Because of this, there is now a lot of research being done on brain cancer treatments based on nanoformulations.

OBJECTIVE

In this review, the author's primary aim is to elucidate the various nanomedicine for brain cancer therapy. The authors focus primarily on the advancement of nanotechnology in treating brain cancer (BC). This review article gives readers an up-to-date look at publications on sophisticated nanosystems in treating BC, including quantum dots (QDs), nanoparticles (NPs), polymeric micelles (PMs), dendrimers, and solid lipid nanoparticles (SLNs), among others. This article offers insight into the use of various nanotechnology-based systems for therapy as well as their potential in the future. This article also emphasizes the drawbacks of nanotechnology-based methods. Future perspectives for treating brain cancer using proteomics and biomimetic nanosystems are briefly discussed.

CONCLUSION

In this review, we review several aspects of brain cancer therapy, including various nanomedicines, their challenges and future perspectives. Overall, this article gives a thorough overview of both the present state of brain cancer treatment options and the disease itself. Various patents granted for brain cancer are also discussed.

Synaptic vesicle protein 2-targeted doxorubicin-loaded liposome for effective neuroblastoma therapy

Neuroblastoma, a pediatric cancer originating from neural crest tissues of the sympathetic nervous system, poses significant treatment challenges due to its molecular diversity and restricted druggable targets. While chemotherapy is a common treatment, its drawbacks, including poor targeting of cancer cells and nonspecific cytotoxicity, highlight the urgent need for innovative and effective therapeutic strategies. Herein, we developed a novel drug by coupling the receptor binding domain of botulinum neurotoxin type A (Hc) fused with monomeric streptavidin (mSA) to biotin coated doxorubicin (Dox)-loaded liposome, via interaction between mSA and biotin. The resultant Hc-coated liposome (Hc-Lipo@Dox) actively targeted the recycling synaptic vesicle 2 protein (SV2) abundantly expressed on the surface of neuroblastoma cells. Our results revealed that Hc-Lipo@Dox more effectively entered the neuroblastoma SH-SY5Y cells, inducing apoptosis compared to non-targeted liposome and free Dox. Moreover, Hc-Lipo@Dox rapidly enriched Dox in the subcutaneously implanted neuroblastoma tumor in nude mice, resulting potent anti-neuroblastoma effect compared to non-targeted liposomes or free Dox. Importantly, Hc-Lipo@Dox significantly improved the survival rate of treated mice, while also exhibiting a favorable safety profile with no discernible impact on mobility or observable side effects. These findings highlight the potential of SV2-targeted Dox liposome as a promising and well-tolerated chemotherapy approach for neuroblastoma treatment. Moreover, the technology established here has broader applications for various cancer therapies by substituting the Hc moiety with other tumor-specific targeting moieties.

Stimuli-Responsive Polymeric Nanocarriers Accelerate On-Demand Drug Release to Combat Glioblastoma

Glioblastoma multiforme (GBM) is a highly malignant brain tumor with a poor prognosis and limited treatment options. Drug delivery by stimuli-responsive nanocarriers holds great promise for improving the treatment modalities of GBM. At the beginning of the review, we highlighted the stimuli-active polymeric nanocarriers carrying therapies that potentially boost anti-GBM responses by employing endogenous (pH, redox, hypoxia, enzyme) or exogenous stimuli (light, ultrasonic, magnetic, temperature, radiation) as triggers for controlled drug release mainly via hydrophobic/hydrophilic transition, degradability, ionizability, etc. Modifying these nanocarriers with target ligands further enhanced their capacity to traverse the blood-brain barrier (BBB) and preferentially accumulate in glioma cells. These unique features potentially lead to more effective brain cancer treatment with minimal adverse reactions and superior therapeutic outcomes. Finally, the review summarizes the existing difficulties and future prospects in stimuli-responsive nanocarriers for treating GBM. Overall, this review offers theoretical guidelines for developing intelligent and versatile stimuli-responsive nanocarriers to facilitate precise drug delivery and treatment of GBM in clinical settings.

Brain targeted biomimetic siRNA nanoparticles for drug resistance glioblastoma treatment

Glioblastoma multiforme (GBM), the most aggressive intracranial neoplasm, remains incurable at present, primarily due to drug resistance, which significantly contributes to elevated recurrence rates and dismal prognosis. Signal transducer and activator of transcription 3 (STAT3) is a critical gene closely associated with GBM drug resistance and the progression of GBM stem cells (GSCs), making it a promising therapeutic target. In this study, we developed cancer cell membrane-cloaked biomimetic nanoparticles to deliver STAT3 siRNA to reverse drug resistance in homologous GBM. These biomimetic nanoparticles leverage homotypic targeting, rapid endosome escape, and fast siRNA release, leading to efficient in vitro STAT3 knockdown in both temozolomide-resistant U251-TR cells and X01 GSCs. Moreover, benefited from the membrane functionalization, significant prolonged blood circulation, improved blood brain barrier (BBB) penetration and GBM tumor accumulation are achieved by these siRNA biomimetic nanoparticles. Importantly, these nanoparticles effectively inhibit tumor proliferation, significantly extending median survival time in orthotopic U251-TR (43.5 d versus 20 d for PBS control) and X01 GSC-bearing mouse xenografts (52 d versus 19.5 d for PBS control). Altogether, this biomimetic siRNA platform offers a promising strategy for gene therapy targeting drug-resistant GBM.

Blood-Brain Barrier Conquest in Glioblastoma Nanomedicine: Strategies, Clinical Advances, and Emerging Challenges

Glioblastoma (GBM) is a prevalent type of malignancy within the central nervous system (CNS) that is associated with a poor prognosis. The standard treatment for GBM includes the surgical resection of the tumor, followed by radiotherapy and chemotherapy; yet, despite these interventions, overall treatment outcomes remain suboptimal. The blood-brain barrier (BBB), which plays a crucial role in maintaining the stability of brain tissue under normal physiological conditions of the CNS, also poses a significant obstacle to the effective delivery of therapeutic agents to GBMs. Recent preclinical studies have demonstrated that nanomedicine delivery systems (NDDSs) offer promising results, demonstrating both effective GBM targeting and safety, thereby presenting a potential solution for targeted drug delivery. In this review, we first explore the various strategies employed in preclinical studies to overcome the BBB for drug delivery. Subsequently, the results of the clinical translation of NDDSs are summarized, highlighting the progress made. Finally, we discuss potential strategies for advancing the development of NDDSs and accelerating their translational research through well-designed clinical trials in GBM therapy.

Brain-Targeted Cas12a Ribonucleoprotein Nanocapsules Enable Synergetic Gene Co-Editing Leading to Potent Inhibition of Orthotopic Glioblastoma

Gene-editing technology shows great potential in glioblastoma (GBM) therapy. Due to the complexity of GBM pathogenesis, a single gene-editing-based therapy is unlikely to be successful; therefore, a multi-gene knockout strategy is preferred for effective GBM inhibition. Here, a non-invasive, biodegradable brain-targeted CRISPR/Cas12a nanocapsule is used that simultaneously targeted dual oncogenes, EGFR and PLK1, for effective GBM therapy. This cargo nanoencapsulation technology enables the CRISPR/Cas12a system to achieve extended blood half-life, efficient blood-brain barrier (BBB) penetration, active tumor targeting, and selective release. In U87MG cells, the combinatorial gene editing system resulted in 61% and 33% knockout of EGFR and PLK1, respectively. Following systemic administration, the CRISPR/Cas12a system demonstrated promising brain tumor accumulation that led to extensive EGFR and PLK1 gene editing in both U87MG and patient-derived GSC xenograft mouse models with negligible off-target gene editing detected through NGS. Additionally, CRISPR/Cas12a nanocapsules that concurrently targeted the EGFR and PLK1 oncogenes showed superior tumor growth suppression and significantly improved the median survival time relative to nanocapsules containing single oncogene knockouts, signifying the potency of the multi-oncogene targeting strategy. The findings indicate that utilization of the CRISPR/Cas12a combinatorial gene editing technique presents a practical option for gene therapy in GBM.

Size-Dependent Glioblastoma Targeting by Polymeric Nanoruler with Prolonged Blood Circulation

Currently, there is no effective treatment for glioblastoma multiforme (GBM), the most frequent and malignant type of brain tumor. The blood-brain (tumor) barrier (BB(T)B), which is composed of tightly connected endothelial cells and pericytes (with partial vasculature collapse), hampers nanomedicine accumulation in tumor tissues. We aimed to explore the effect of nanomedicine size on passive targeting of GBM. A series of size-tunable poly(ethylene glycol) (PEG)-grafted copolymers (gPEGs) were constructed with hydrodynamic diameters of 8-30 nm. Biodistribution studies using orthotopic brain tumor-bearing mice revealed that gPEG brain tumor accumulation was maximized at 10 nm with ∼14 dose %/g of tumor, which was 19 times higher than that in the normal brain region and 4.2 times higher than that of 30-nm gPEG. Notably, 10-nm gPEG exhibited substantially higher brain tumor accumulation than 11-nm linear PEG owing to the prolonged blood circulation property of gPEGs, which is derived from a densely PEG-packed structure. 10 nm gPEG exhibited deeper penetration into the brain tumor tissue than the larger gPEGs did (>10 nm). This study demonstrates, for the first time, the great potential of a nanomedicine downsizing strategy for passive GBM targeting.

Biomedical applications of stimuli-responsive nanomaterials

Nanomaterials have aroused great interests in drug delivery due to their nanoscale structure, facile modifiability, and multifunctional physicochemical properties. Currently, stimuli-responsive nanomaterials that can respond to endogenous or exogenous stimulus display strong potentials in biomedical applications. In comparison with conventional nanomaterials, stimuli-responsive nanomaterials can improve therapeutic efficiency and reduce the toxicity of drugs toward normal tissues through specific targeting and on-demand drug release at pathological sites. In this review, we summarize the responsive mechanism of a variety of stimulus, including pH, redox, and enzymes within pathological microenvironment, as well as exogenous stimulus such as thermal effect, magnetic field, light, and ultrasound. After that, biomedical applications (e.g., drug delivery, imaging, and theranostics) of stimuli-responsive nanomaterials in a diverse array of common diseases, including cardiovascular diseases, cancer, neurological disorders, inflammation, and bacterial infection, are presented and discussed. Finally, the remaining challenges and outlooks of future research directions for the biomedical applications of stimuli-responsive nanomaterials are also discussed. We hope that this review can provide valuable guidance for developing stimuli-responsive nanomaterials and accelerate their biomedical applications in diseases diagnosis and treatment.

PEG length effect of peptide-functional liposome for blood brain barrier (BBB) penetration and brain targeting

Nanoparticles, in particular PEGylated, show great potential for in vivo brain targeted drug delivery. Nevertheless, how polyethylene glycol (PEG) length of nanoparticles affects their blood brain barrier (BBB) penetration or brain targeting is still unclear. In this study, we investigated the power of PEG chain-lengths (2, 3.4, 5, 10 kDa) in BBB penetration and brain targeting using Angiopep-2 peptide decorated liposomes. We found that PEG chain-length is critical, where the shorter PEG enabled the Angiopep-2 decorated liposomes to display more potent in vitro cell uptake via endocytosis. In contrast, their in vitro BBB penetration via transcytosis was much weaker relative to the liposomes with longer PEG chains, which result from their ineffective BBB exocytosis. Interestingly, the in vivo brain targeting aligns with the in vitro BBB penetration, as the long chain PEG-modified liposomes exerted superior brain accumulation both in normal or orthotropic glioblastoma (GBM) bearing mice, which could be ascribed to the combinational effect of prolonged circulation and enhanced BBB penetration of long chain PEG attached liposomes. These results demonstrate the crucial role of PEG length of nanoparticles for BBB penetration and brain targeting, providing guidance for PEG length selection in the design of nanocarrier for brain diseases treatment.

Peptide-Hitchhiking for the Development of Nanosystems in Glioblastoma

Glioblastoma (GBM) remains the epitome of aggressiveness and lethality in the spectrum of brain tumors, primarily due to the blood-brain barrier (BBB) that hinders effective treatment delivery, tumor heterogeneity, and the presence of treatment-resistant stem cells that contribute to tumor recurrence. Nanoparticles (NPs) have been used to overcome these obstacles by attaching targeting ligands to enhance therapeutic efficacy. Among these ligands, peptides stand out due to their ease of synthesis and high selectivity. This article aims to review single and multiligand strategies critically. In addition, it highlights other strategies that integrate the effects of external stimuli, biomimetic approaches, and chemical approaches as nanocatalytic medicine, revealing their significant potential in treating GBM with peptide-functionalized NPs. Alternative routes of parenteral administration, specifically nose-to-brain delivery and local treatment within the resected tumor cavity, are also discussed. Finally, an overview of the significant obstacles and potential strategies to overcome them are discussed to provide a perspective on this promising field of GBM therapy.

An Overview on the Physiopathology of the Blood-Brain Barrier and the Lipid-Based Nanocarriers for Central Nervous System Delivery

The state of well-being and health of our body is regulated by the fine osmotic and biochemical balance established between the cells of the different tissues, organs, and systems. Specific districts of the human body are defined, kept in the correct state of functioning, and, therefore, protected from exogenous or endogenous insults of both mechanical, physical, and biological nature by the presence of different barrier systems. In addition to the placental barrier, which even acts as a linker between two different organisms, the mother and the fetus, all human body barriers, including the blood-brain barrier (BBB), blood-retinal barrier, blood-nerve barrier, blood-lymph barrier, and blood-cerebrospinal fluid barrier, operate to maintain the physiological homeostasis within tissues and organs. From a pharmaceutical point of view, the most challenging is undoubtedly the BBB, since its presence notably complicates the treatment of brain disorders. BBB action can impair the delivery of chemical drugs and biopharmaceuticals into the brain, reducing their therapeutic efficacy and/or increasing their unwanted bioaccumulation in the surrounding healthy tissues. Recent nanotechnological innovation provides advanced biomaterials and ad hoc customized engineering and functionalization methods able to assist in brain-targeted drug delivery. In this context, lipid nanocarriers, including both synthetic (liposomes, solid lipid nanoparticles, nanoemulsions, nanostructured lipid carriers, niosomes, proniosomes, and cubosomes) and cell-derived ones (extracellular vesicles and cell membrane-derived nanocarriers), are considered one of the most successful brain delivery systems due to their reasonable biocompatibility and ability to cross the BBB. This review aims to provide a complete and up-to-date point of view on the efficacy of the most varied lipid carriers, whether FDA-approved, involved in clinical trials, or used in in vitro or in vivo studies, for the treatment of inflammatory, cancerous, or infectious brain diseases.

Efficient Delivery of Lomitapide using Hybrid Membrane-Coated Tetrahedral DNA Nanostructures for Glioblastoma Therapy

Glioblastoma (GBM) is the most aggressive and prevalent primary malignant tumor of the central nervous system. Traditional chemotherapy has poor therapeutic effects and significant side effects due to drug resistance, the natural blood-brain barrier (BBB), and nonspecific distribution, leading to a lack of clinically effective therapeutic drugs. Here, 1430 small molecule compounds are screened based on a high-throughput drug screening platform and a novel anti-GBM drug, lomitapide (LMP) is obtained. Furthermore, a bionic nanodrug delivery system (RFA NPs) actively targeting GBM is constructed, which mainly consists of tetrahedral DNA nanocages (tFNA NPs) loaded with LMP as the core and a folate-modified erythrocyte-cancer cell-macrophage hybrid membrane (FRUR) as the shell. FRUR camouflage conferred unique features on tFNA NPs, including excellent biocompatibility, improved pharmacokinetic profile, efficient BBB permeability, and tumor targeting ability. The results show that the LMP RFA NPs exhibited superior and specific anti-GBM activities, reduced off-target drug delivery, prolonged lifespan, and has negligible side effects in tumor-bearing mice. This study combines high-throughput drug screening with biomimetic nanodrug delivery system technology to provide a theoretical and practical basis for drug development and the optimization of clinical treatment strategies for GBM treatment.

Application and advances of biomimetic membrane materials in central nervous system disorders

Central nervous system (CNS) diseases encompass spinal cord injuries, brain tumors, neurodegenerative diseases, and ischemic strokes. Recently, there has been a growing global recognition of CNS disorders as a leading cause of disability and death in humans and the second most common cause of death worldwide. The global burdens and treatment challenges posed by CNS disorders are particularly significant in the context of a rapidly expanding global population and aging demographics. The blood-brain barrier (BBB) presents a challenge for effective drug delivery in CNS disorders, as conventional drugs often have limited penetration into the brain. Advances in biomimetic membrane nanomaterials technology have shown promise in enhancing drug delivery for various CNS disorders, leveraging properties such as natural biological surfaces, high biocompatibility and biosafety. This review discusses recent developments in biomimetic membrane materials, summarizes the types and preparation methods of these materials, analyzes their applications in treating CNS injuries, and provides insights into the future prospects and limitations of biomimetic membrane materials.

Recent advances in targeted drug delivery for the treatment of glioblastoma

Glioblastoma multiforme (GBM) is one of the highly malignant brain tumors characterized by significant morbidity and mortality. Despite the recent advancements in the treatment of GBM, major challenges persist in achieving controlled drug delivery to tumors. The management of GBM poses considerable difficulties primarily due to unresolved issues in the blood-brain barrier (BBB)/blood-brain tumor barrier (BBTB) and GBM microenvironment. These factors limit the uptake of anti-cancer drugs by the tumor, thus limiting the therapeutic options. Current breakthroughs in nanotechnology provide new prospects concerning unconventional drug delivery approaches for GBM treatment. Specifically, swimming nanorobots show great potential in active targeted delivery, owing to their autonomous propulsion and improved navigation capacities across biological barriers, which further facilitate the development of GBM-targeted strategies. This review presents an overview of technological progress in different drug administration methods for GBM. Additionally, the limitations in clinical translation and future research prospects in this field are also discussed. This review aims to provide a comprehensive guideline for researchers and offer perspectives on further development of new drug delivery therapies to combat GBM.

Hopping the Hurdle: Strategies to Enhance the Molecular Delivery to the Brain through the Blood-Brain Barrier

Modern medicine has allowed for many advances in neurological and neurodegenerative disease (ND). However, the number of patients suffering from brain diseases is ever increasing and the treatment of brain diseases remains an issue, as drug efficacy is dramatically reduced due to the existence of the unique vascular structure, namely the blood-brain barrier (BBB). Several approaches to enhance drug delivery to the brain have been investigated but many have proven to be unsuccessful due to limited transport or damage induced in the BBB. Alternative approaches to enhance molecular delivery to the brain have been revealed in recent studies through the existence of molecular delivery pathways that regulate the passage of peripheral molecules. In this review, we present recent advancements of the basic research for these delivery pathways as well as examples of promising ventures to overcome the molecular hurdles that will enhance therapeutic interventions in the brain and potentially save the lives of millions of patients.

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

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

Stepwise targeted strategies for improving neurological function by inhibiting oxidative stress levels and inflammation following ischemic stroke

Ischemia-reperfusion injury is caused by excessive production of reactive oxygen species (ROS) and inflammation accompanied by ischemic injury symptoms and blood-brain barrier (BBB) dysfunction. This causes neuronal damage, for which no effective treatments or drugs exist. Herein, we provided a stepwise targeted drug delivery strategy and successfully prepared multifunctional ORD@SHp@ANG nanoparticles (NPs) that consist of a stroke homing peptide (DSPE-PEG2000-SHp), BBB-targeting peptide (DSPE-PEG2000-ANG), and ROS-responsive Danshensu (salvianic acid A) chain self-assembly. ORD@SHp@ANG NPs effectively crossed the BBB by ANG peptide and selectively targeted the ischemic brain sites using stroke-homing peptide. The results showed that ORD@SHp@ANG NPs can effective at scavenging ROS, and protect SH-SY5Y cells from oxidative damage in vitro. Furthermore, ORD@SHp@ANG NPs showed excellent biocompatibility. These NPs recognized brain endothelial cells and crossed the BBB, regulated the transformation of microglia into the anti-inflammatory phenotype, and inhibited the production of inflammatory factors in a rat ischemia-reperfusion model, thereby reducing cerebral infarction, neuronal apoptosis and preserving BBB integrity. Sequencing revealed that ORD@SHp@ANG NPs promote cell proliferation, activate immune responses, suppress inflammatory responses, and ameliorate ischemic stroke. In conclusion, this study reports a simple and promising drug delivery strategy for managing ischemic stroke.

Engineered smart materials for RNA based molecular therapy to treat Glioblastoma

Glioblastoma (GBM) is an aggressive malignancy of the central nervous system (CNS) that remains incurable despite the multitude of improvements in cancer therapeutics. The conventional chemo and radiotherapy post-surgery have only been able to improve the prognosis slightly; however, the development of resistance and/or tumor recurrence is almost inevitable. There is a pressing need for adjuvant molecular therapies that can successfully and efficiently block tumor progression. During the last few decades, non-coding RNAs (ncRNAs) have emerged as key players in regulating various hallmarks of cancer including that of GBM. The levels of many ncRNAs are dysregulated in cancer, and ectopic modulation of their levels by delivering antagonists or overexpression constructs could serve as an attractive option for cancer therapy. The therapeutic potential of several types of ncRNAs, including miRNAs, lncRNAs, and circRNAs, has been validated in both in vitro and in vivo models of GBM. However, the delivery of these RNA-based therapeutics is highly challenging, especially to the tumors of the brain as the blood-brain barrier (BBB) poses as a major obstacle, among others. Also, since RNA is extremely fragile in nature, careful considerations must be met while designing a delivery agent. In this review we have shed light on how ncRNA therapy can overcome the limitations of its predecessor conventional therapy with an emphasis on smart nanomaterials that can aide in the safe and targeted delivery of nucleic acids to treat GBM. Additionally, critical gaps that currently exist for successful transition from viral to non-viral vector delivery systems have been identified. Finally, we have provided a perspective on the future directions, potential pathways, and target areas for achieving rapid clinical translation of, RNA-based macromolecular therapy to advance the effective treatment of GBM and other related diseases.

Engineered bacterial extracellular vesicles for central nervous system diseases

The prevalence of central nervous system (CNS) diseases is on the rise as the population ages. The presence of various obstacles, particularly the blood-brain barrier (BBB), poses a challenge for drug delivery to the CNS. An expanding body of study suggests that gut microbiota (GM) plays an important role in CNS diseases. The communication between GM and CNS diseases has received increasing attention. Accumulating evidence indicates that the GM can modulate host signaling pathways to regulate distant organ functions by delivering bioactive substances to host cells via bacterial extracellular vesicles (BEVs). BEVs have emerged as a promising platform for the treatment of CNS diseases due to their nanostructure, ability to penetrate the BBB, as well as their low toxicity, high biocompatibility, ease of modification and large-scale culture. Here, we discuss the biogenesis, internalization mechanism and engineering modification methods of BEVs. We then focus on the use and potential role of BEVs in the treatment of CNS diseases. Finally, we outline the main challenges and future prospects for the application of BEVs in CNS diseases. We hope that the comprehensive understanding of the BEVs-based gut-brain axis will provide new insights into the treatment of CNS diseases.

Surface modification strategies in translocating nano-vesicles across different barriers and the role of bio-vesicles in improving anticancer therapy

Nanovesicles and bio-vesicles (BVs) have emerged as promising tools to achieve targeted cancer therapy due to their ability to overcome many of the key challenges currently being faced with conventional chemotherapy. These challenges include the diverse and often complex pathophysiology involving the progression of cancer, as well as the various biological barriers that circumvent therapeutic molecules reaching their target site in optimum concentration. The scientific evidence suggests that surface-functionalized nanovesicles and BVs camouflaged nano-carriers (NCs) both can bypass the established biological barriers and facilitate fourth-generation targeting for the improved regimen of treatment. In this review, we intend to emphasize the role of surface-functionalized nanovesicles and BVs camouflaged NCs through various approaches that lead to an improved internalization to achieve improved and targeted oncotherapy. We have explored various strategies that have been employed to surface-functionalize and biologically modify these vesicles, including the use of biomolecule functionalized target ligands such as peptides, antibodies, and aptamers, as well as the targeting of specific receptors on cancer cells. Further, the utility of BVs, which are made from the membranes of cells such as mesenchymal stem cells (MSCs), white blood cells (WBCs), red blood cells (RBCs), platelets (PLTs) as well as cancer cells also been investigated. Lastly, we have discussed the translational challenges and limitations that these NCs can encounter and still need to be overcome in order to fully realize the potential of nanovesicles and BVs for targeted cancer therapy. The fundamental challenges that currently prevent successful cancer therapy and the necessity of novel delivery systems are in the offing.

Fruit-Derived Extracellular-Vesicle-Engineered Structural Droplet Drugs for Enhanced Glioblastoma Chemotherapy

Existing solid-nanoparticle-based drug delivery systems remain a great challenge for glioblastoma chemotherapy due to their poor capacities in crossing the blood-brain barrier/blood-brain tumor barrier (BBB/BBTB). Herein, fruit-derived extracellular-vesicle (EV)-engineered structural droplet drugs (ESDDs) are demonstrated by programming the self-assembly of fruit-derived EVs at the DOX@squalene-PBS interface, greatly enhancing the antitumor efficacy against glioblastoma. The ESDDs experience a flexible delivery via deformation-amplified macropinocytosis and membrane fusion, enabling them to highly efficiently cross the BBB/BBTB and deeply penetrate glioblastoma tissues. As expected, the ESDDs exhibit approximately 2.5-fold intracellular uptake, 2.2-fold transcytosis, and fivefold membrane fusion higher than cRGD-modified EVs (REs), allowing highly efficient accumulation, deep penetration, and cellular internalization into the glioblastoma tissues, and thereby significantly extending the survival time of glioblastoma mice.

Cell membrane-based nanomaterials for therapeutics of neurodegenerative diseases

Central nervous system (CNS) diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), glioblastoma (GBM), and peripheral nerve injury have been documented as incurable diseases, which lead to serious impacts on human health especially prevalent in the aging population worldwide. Most of the treatment strategies fail due to low efficacy, toxicity, and poor brain penetration. Recently, advancements in nanotechnology have helped alleviate the challenges associated with the application of cell membrane-based nanomaterials against CNS diseases. In the following review, the existing types of cell membrane-based nanomaterials systems which have improved therapeutic efficacy for CNS diseases would be described. A summary of recent progress in the incorporation of nanomaterials in cell membrane-based production, separation, and analysis will be provided. Addition to, challenges relate to large-scale manufacturing of cell membrane-based nanomaterials and future clinical trial of such platforms will be discussed.

Strategies for Drug Delivery into the Brain: A Review on Adenosine Receptors Modulation for Central Nervous System Diseases Therapy

The blood-brain barrier (BBB) is a biological barrier that protects the central nervous system (CNS) by ensuring an appropriate microenvironment. Brain microvascular endothelial cells (ECs) control the passage of molecules from blood to brain tissue and regulate their concentration-versus-time profiles to guarantee proper neuronal activity, angiogenesis and neurogenesis, as well as to prevent the entry of immune cells into the brain. However, the BBB also restricts the penetration of drugs, thus presenting a challenge in the development of therapeutics for CNS diseases. On the other hand, adenosine, an endogenous purine-based nucleoside that is expressed in most body tissues, regulates different body functions by acting through its G-protein-coupled receptors (A1, A2A, A2B and A3). Adenosine receptors (ARs) are thus considered potential drug targets for treating different metabolic, inflammatory and neurological diseases. In the CNS, A1 and A2A are expressed by astrocytes, oligodendrocytes, neurons, immune cells and ECs. Moreover, adenosine, by acting locally through its receptors A1 and/or A2A, may modulate BBB permeability, and this effect is potentiated when both receptors are simultaneously activated. This review showcases in vivo and in vitro evidence supporting AR signaling as a candidate for modifying endothelial barrier permeability in the treatment of CNS disorders.

Engineering and Characterization of an Artificial Drug-Carrying Vesicles Nanoplatform for Enhanced Specifically Targeted Therapy of Glioblastoma

Glioblastoma multiforme (GBM) treatment is hindered by complex pathologies and the need to cross the blood-brain barrier (BBB) during drug delivery. Although exosomes have great potential for GBM treatment, these alone cannot fully meet the therapeutic requirements, owing to their limitations in targeting and delivery. Herein, engineered artificial vesicles (EAVs), ANG-TRP-PK1@EAVs, which are constructed using a liposome extruder from HEK293T cells expressing ANG-TRP-PK1 peptides, is developed. ANG-TRP-PK1 is a fusion peptide of Angiopep-2 fused to the N-terminus of TRP-PK1, to present Angiopep-2 on the EAVs. ANG-TRP-PK1@EAVs have similar characteristics to the secreted exosomes, but a much higher yield. ANG-TRP-PK1@EAVs have efficient BBB-penetration and GBM-targeting abilities in a mock BBB model in in vitro and orthotopic GBM mouse models in vivo. Doxorubicin loading EAVs (ANG-TRP-PK1@DOX) do not alter the characteristics of the EAVs, which can cross the BBB, reach the GBM, and kill tumor cells in orthotopic GBM mouse models. These engineered drug-loaded artificial vesicles show better therapeutic effects on GBM than temozolomide in mice, with very few side effects. In conclusion, EAVs can be inserted into different targeting ligands and packed into different drugs, and they may serve as unique and efficient nanoplatforms for drug delivery and tumor promise therapy.

Cell membrane-based nanomaterials for theranostics of central nervous system diseases

Central nervous system (CNS) diseases have been widely acknowledged as one of the major healthy concerns globally, which lead to serious impacts on human health. There will be about 135 million CNS diseases cases worldwide by mid-century, and CNS diseases will become the second leading cause of death after the cardiovascular disease by 2040. Most CNS diseases lack of effective diagnostic and therapeutic strategies with one of the reasons that the biological barrier extremely hampers the delivery of theranostic agents. In recent years, nanotechnology-based drug delivery is a quite promising way for CNS diseases due to excellent properties. Among them, cell membrane-based nanomaterials with natural bio-surface, high biocompatibility and biosafety, are of great significance in both the diagnosis and treatment of different CNS diseases. In this review, the state of art of the fabrication of cell membranes-based nanomaterials is introduced. The characteristics of different CNS diseases, and the application of cell membranes-based nanomaterials in the theranostics are summarized. In addition, the future prospects and limitations of cell membrane nanotechnology are anticipated. Through summarizing the state of art of the fabrication, giving examples of CNS diseases, and highlighting the applications in theranostics, the current review provides designing methods and ideas for subsequent cell membrane nanomaterials.

Exosome-sheathed ROS-responsive nanogel to improve targeted therapy in perimenopausal depression

The development of natural membranes as coatings for nanoparticles to traverse the blood-brain barrier (BBB) presents an effective approach for treating central nervous system (CNS) disorders. In this study, we have designed a nanogel loaded with PACAP and estrogen (E2), sheathed with exosomes and responsive to reactive oxygen species (ROS), denoted as HA NGs@exosomes. The objective of this novel design is to serve as a potent drug carrier for the targeted treatment of perimenopausal depression. The efficient cellular uptake and BBB penetration of HA NGs@exosomes has been demonstrated in vitro and in vivo. Following intranasal intervention with HA NGs@exosomes, ovariectomized mice under chronic unpredictable mild stress (CUMS) have shown improved behavioral performance, indicating that HA NGs@exosomes produced a rapid-onset antidepressant effect. Moreover, HA NGs@exosomes exhibit notable antioxidant and anti-inflammatory properties and may regulate the expression of pivotal proteins in the PACAP/PAC1 pathway to promote synaptic plasticity. Our results serve as a proof-of-concept for the utility of exosome-sheathed ROS-responsive nanogel as a promising drug carrier for the treatment of perimenopausal depression.

A Multifunctional Nanocarrier System for Highly Efficient and Targeted Delivery of Ketamine to NMDAR Sites for Improved Treatment of Depression

Ketamine (KA), commonly used as an anesthetic, is now widely studied as an antidepressant for the treatment of depression. However, due to its side effects, such as addiction and cognitive impairment, the dosage and frequency of (S)-ketamine approved by the FDA for the treatment of refractory depression is very low, which limits its efficacy. Here, a new multifunctional nanocarrier system (AC-RM@HA-MS) with specific targeting capabilities is developed to improve the efficacy of KA treatment. KA-loaded NPs (AC-RM@HA-MS-KA) are constructed with a multilayer core-shell structure. KA-loaded mesoporous silica NPs are prepared, conjugated with hyaluronic acid (HA) as pore gatekeepers, and sheathed with an RBC-membrane (RM) for camouflage. Finally, the surface is tagged with bifunctional peptides (Ang-2-Con-G, AC) to achieve specific targeting. One peptide (Ang-2) is acted as a guide to facilitate the crossing of the blood-brain barrier (BBB), while the other (Con-G) is functioned as a ligand for the targeted delivery of KA to the N-methyl-D-aspartate receptor sites. Animal experiments reveal that AC-RM@HA-MS-KA NPs effectively cross the BBB and directionally accumulate in the curing areas, thereby alleviating the depressive symptoms and improving the cognitive functions of depressed mice. After treatment, the depressed mice almost completely return to normal without obvious symptoms of addiction.

Cancer cell-mitochondria hybrid membrane coated Gboxin loaded nanomedicines for glioblastoma treatment

Glioblastoma (GBM) remains the most lethal malignant tumours. Gboxin, an oxidative phosphorylation inhibitor, specifically restrains GBM growth by inhibiting the activity of F₀F₁ ATPase complex V. However, its anti-GBM effect is seriously limited by poor blood circulation, the blood brain barrier (BBB) and non-specific GBM tissue/cell uptake, leading to insufficient Gboxin accumulation at GBM sites, which limits its further clinical application. Here we present a biomimetic nanomedicine (HM-NPs@G) by coating cancer cell-mitochondria hybrid membrane (HM) on the surface of Gboxin-loaded nanoparticles. An additional design element uses a reactive oxygen species responsive polymer to facilitate at-site Gboxin release. The HM camouflaging endows HM-NPs@G with unique features including good biocompatibility, improved pharmacokinetic profile, efficient BBB permeability and homotypic dual tumour cell and mitochondria targeting. The results suggest that HM-NPs@G achieve improved blood circulation (4.90 h versus 0.47 h of free Gboxin) and tumour accumulation (7.73% ID/g versus 1.06% ID/g shown by free Gboxin). Effective tumour inhibition in orthotopic U87MG GBM and patient derived X01 GBM stem cell xenografts in female mice with extended survival time and negligible side effects are also noted. We believe that the biomimetic Gboxin nanomedicine represents a promising treatment for brain tumours with clinical potential.

How Nanotherapeutic Platforms Play a Key Role in Glioma? A Comprehensive Review of Literature

Glioblastoma (GBM), a highly aggressive form of brain cancer, is considered one of the deadliest cancers, and even with the most advanced medical treatments, most affected patients have a poor prognosis. However, recent advances in nanotechnology offer promising avenues for the development of versatile therapeutic and diagnostic nanoplatforms that can deliver drugs to brain tumor sites through the blood-brain barrier (BBB). Despite these breakthroughs, the use of nanoplatforms in GBM therapy has been a subject of great controversy due to concerns over the biosafety of these nanoplatforms. In recent years, biomimetic nanoplatforms have gained unprecedented attention in the biomedical field. With advantages such as extended circulation times, and improved immune evasion and active targeting compared to conventional nanosystems, bionanoparticles have shown great potential for use in biomedical applications. In this prospective article, we endeavor to comprehensively review the application of bionanomaterials in the treatment of glioma, focusing on the rational design of multifunctional nanoplatforms to facilitate BBB infiltration, promote efficient accumulation in the tumor, enable precise tumor imaging, and achieve remarkable tumor suppression. Furthermore, we discuss the challenges and future trends in this field. Through careful design and optimization of nanoplatforms, researchers are paving the way toward safer and more effective therapies for GBM patients. The development of biomimetic nanoplatform applications for glioma therapy is a promising avenue for precision medicine, which could ultimately improve patient outcomes and quality of life.

Influence factors on and potential strategies to amplify receptor-mediated nanodrug delivery across the blood-brain barrier

INTRODUCTION

A major challenge in treating central nervous system (CNS) disorders is to achieve adequate drug delivery across the blood-brain barrier (BBB). Receptor-mediated nanodrug delivery as a Trojan horse strategy has become an exciting approach. However, these nanodrugs do not accumulate significantly in the brain parenchyma, which greatly limits the therapeutic effect of drugs. Amplifying the efficiency of receptor-mediated nanodrug delivery across the BBB becomes the holy grail in the treatment of CNS disorders.

AREAS COVERED

In this review, we tend to establish links between dynamic BBB and receptor-mediated nanodrug delivery, starting with the delivery processes across the BBB, describing factors affecting nanodrug delivery efficiency, and summarizing potential strategies that may amplify delivery efficiency.

EXPERT OPINION

Receptor-mediated nanodrug delivery is a common approach to significantly enhance the efficiency of brain-targeting delivery. As BBB is constantly undergoing changes, it is essential to investigate the impact of diseases on the effectiveness of brain-targeting nanodrug delivery. More critically, there are several barriers to achieving brain-targeting nanodrug delivery in the five stages of receptor-mediated transcytosis (RMT), and the impacts can be conflicting, requiring intricate balance. Further studies are also needed to investigate the material toxicity of nanodrugs to address the issue of clinical translation.

The blood-brain barrier: structure, regulation, and drug delivery

Blood-brain barrier (BBB) is a natural protective membrane that prevents central nervous system (CNS) from toxins and pathogens in blood. However, the presence of BBB complicates the pharmacotherapy for CNS disorders as the most chemical drugs and biopharmaceuticals have been impeded to enter the brain. Insufficient drug delivery into the brain leads to low therapeutic efficacy as well as aggravated side effects due to the accumulation in other organs and tissues. Recent breakthrough in materials science and nanotechnology provides a library of advanced materials with customized structure and property serving as a powerful toolkit for targeted drug delivery. In-depth research in the field of anatomical and pathological study on brain and BBB further facilitates the development of brain-targeted strategies for enhanced BBB crossing. In this review, the physiological structure and different cells contributing to this barrier are summarized. Various emerging strategies for permeability regulation and BBB crossing including passive transcytosis, intranasal administration, ligands conjugation, membrane coating, stimuli-triggered BBB disruption, and other strategies to overcome BBB obstacle are highlighted. Versatile drug delivery systems ranging from organic, inorganic, and biologics-derived materials with their synthesis procedures and unique physio-chemical properties are summarized and analyzed. This review aims to provide an up-to-date and comprehensive guideline for researchers in diverse fields, offering perspectives on further development of brain-targeted drug delivery system.

Therapeutic and Diagnostic Potential of Exosomes as Drug Delivery Systems in Brain Cancer

Cancer is designated as one of the principal causes of mortality universally. Among different types of cancer, brain cancer remains the most challenging one due to its aggressiveness, the ineffective permeation ability of drugs through the blood-brain barrier (BBB), and drug resistance. To overcome the aforementioned issues in fighting brain cancer, there is an imperative need for designing novel therapeutic approaches. Exosomes have been proposed as prospective "Trojan horse" nanocarriers of anticancer theranostics owing to their biocompatibility, increased stability, permeability, negligible immunogenicity, prolonged circulation time, and high loading capacity. This review provides a comprehensive discussion on the biological properties, physicochemical characteristics, isolation methods, biogenesis and internalization of exosomes, while it emphasizes their therapeutic and diagnostic potential as drug vehicle systems in brain cancer, highlighting recent advances in the research field. A comparison of the biological activity and therapeutic effectiveness of several exosome-encapsulated cargo including drugs and biomacromolecules underlines their great supremacy over the non-exosomal encapsulated cargo in the delivery, accumulation, and biological potency. Various studies on cell lines and animals give prominence to exosome-based nanoparticles (NPs) as a promising and alternative approach in the management of brain cancer.

Biomimetic Biomembrane Encapsulation and Targeted Delivery of a Nitric Oxide Release Platform for Therapy of Parkinson's Disease

The existence of the blood-brain barrier (BBB) and the complex inflammatory environment in the brain are two major obstacles in the treatment of Parkinson's disease (PD). As a target group, we modified the red blood cell membrane (RBCM) on the surface of upconversion nanoparticles (UCNPs) in this study to effectively target the brain. Mesoporous silicon, coated with UCNPs (UCM), was loaded with S-nitrosoglutathione (GSNO) as the nitric oxide (NO) donor. Then, UCNPs were excited to emit green light (540 nm) by 980 nm near-infrared (NIR). In addition, it produced a light-responsive anti-inflammatory effect by promoting the release of NO from GSNO and lowering the brain's level of proinflammatory factors. A series of experiments demonstrated that this strategy could effectively mitigate the inflammatory response damage of neurons in the brain.

A Bird's Eye View of Various Cell-Based Biomimetic Nanomedicines for the Treatment of Arthritis

Arthritis is the inflammation and tenderness of the joints because of some metabolic, infectious, or constitutional reasons. Existing arthritis treatments help in controlling the arthritic flares, but more advancement is required to cure arthritis meticulously. Biomimetic nanomedicine represents an exceptional biocompatible treatment to cure arthritis by minimizing the toxic effect and eliminating the boundaries of current therapeutics. Various intracellular and extracellular pathways can be targeted by mimicking the surface, shape, or movement of the biological system to form a bioinspired or biomimetic drug delivery system. Different cell-membrane-coated biomimetic systems, and extracellular-vesicle-based and platelets-based biomimetic systems represent an emerging and efficient class of therapeutics to treat arthritis. The cell membrane from various cells such as RBC, platelets, macrophage cells, and NK cells is isolated and utilized to mimic the biological environment. Extracellular vesicles isolated from arthritis patients can be used as diagnostic tools, and plasma or MSCs-derived extracellular vesicles can be used as a therapeutic target for arthritis. Biomimetic systems guide the nanomedicines to the targeted site by hiding them from the surveillance of the immune system. Nanomedicines can be functionalized using targeted ligand and stimuli-responsive systems to reinforce their efficacy and minimize off-target effects. This review expounds on various biomimetic systems and their functionalization for the therapeutic targets of arthritis treatment, and discusses the challenges for the clinical translation of the biomimetic system.

Cell Membrane Biomimetic Nanoparticles with Potential in Treatment of Alzheimer's Disease

Alzheimer's disease (AD) is to blame for about 60% of dementia cases worldwide. The blood-brain barrier (BBB) prevents many medications for AD from having clinical therapeutic effects that can be used to treat the affected area. Many researchers have turned their attention to cell membrane biomimetic nanoparticles (NPs) to solve this situation. Among them, NPs can extend the half-life of drugs in the body as the "core" of the wrapped drug, and the cell membrane acts as the "shell" of the wrapped NPs to functionalize the NPs, which can further improve the delivery efficiency of nano-drug delivery systems. Researchers are learning that cell membrane biomimetic NPs can circumvent the BBB's restriction, prevent harm to the body's immune system, extend the period that NPs spend in circulation, and have good biocompatibility and cytotoxicity, which increases efficacy of drug release. This review summarized the detailed production process and features of core NPs and further introduced the extraction methods of cell membrane and fusion methods of cell membrane biomimetic NPs. In addition, the targeting peptides for modifying biomimetic NPs to target the BBB to demonstrate the broad prospects of cell membrane biomimetic NPs drug delivery systems were summarized.

Macrophage cell membrane infused biomimetic liposomes for glioblastoma targeted therapy

Glioblastoma (GBM) is a highly aggressive malignant brain tumor currently without an effective treatment. Inspired by the recent advances in cell membrane biomimetic nanocarriers and by the key role of macrophages in GBM pathology, we developed macrophage membrane liposomes (MML) for GBM targeting. For the first time, it was assessed the role of macrophage polarization states in the effectiveness of these drug delivery systems. Interestingly, we observed that MML derived from M2 macrophages (M2 MML) presents higher uptake and increased delivery of the anticarcinogenic drug doxorubicin compared to M1 macrophage-derived nanocarriers (M1 MML) and control liposomes (CL). Moreover, the lowest uptake by macrophages of MML reveals promising immune escaping properties. Notably, M2 macrophages unveiled a higher expression of integrin CD49d, a crucial protein involved in the bilateral communication of macrophages with tumor cells. Therefore, our findings suggest the potential of using M2 macrophage membranes to develop novel nanocarriers targeting GBM.

Erythrocyte-Inspired Functional Materials for Biomedical Applications

Erythrocytes are the most abundant cells in the blood. As the results of long-term natural selection, their specific biconcave discoid morphology and cellular composition are responsible for gaining excellent biological performance. Inspired by the intrinsic features of erythrocytes, various artificial biomaterials emerge and find broad prospects in biomedical applications such as therapeutic delivery, bioimaging, and tissue engineering. Here, a comprehensive review from the fabrication to the applications of erythrocyte-inspired functional materials is given. After summarizing the biomaterials mimicking the biological functions of erythrocytes, the synthesis strategies of particles with erythrocyte-inspired morphologies are presented. The emphasis is on practical biomedical applications of these bioinspired functional materials. The perspectives for the future possibilities of the advanced erythrocyte-inspired biomaterials are also discussed. It is hoped that the summary of existing studies can inspire researchers to develop novel biomaterials; thus, accelerating the progress of these biomaterials toward clinical biomedical applications.

Exosomes based strategies for brain drug delivery

Exosome application has emerged as a promising nanotechnology discipline for various diseases therapeutics and diagnoses. Owing to the natural properties of efficient drug delivery, higher biocompatibility, facile traversing of physiological barriers, and subtle side effects, exosomes shorten their way to clinical translation. Exosomes are nanoscale membrane-bound vesicles primarily involved in intercellular communication and exhibit natural blood-brain barrier (BBB) traversing ability, which enables their application as drug delivery vehicles for brain diseases treatment. Herein, we highlight recent exosome-based drug delivery endeavors for neurodegenerative diseases and brain cancer therapy, summarize the obstacles and future directions in clinical translation.

Multifunctional nanoparticle for cancer therapy

Cancer is a complex disease associated with a combination of abnormal physiological process and exhibiting dysfunctions in multiple systems. To provide effective treatment and diagnosis for cancer, current treatment strategies simultaneously focus on various tumor targets. Based on the rapid development of nanotechnology, nanocarriers have been shown to exhibit excellent potential for cancer therapy. Compared with nanoparticles with single functions, multifunctional nanoparticles are believed to be more aggressive and potent in the context of tumor targeting. However, the development of multifunctional nanoparticles is not simply an upgraded version of the original function, but involves a sophisticated system with a proper backbone, optimized modification sites, simple preparation method, and efficient function integration. Despite this, many well-designed multifunctional nanoparticles with promising therapeutic potential have emerged recently. Here, to give a detailed understanding and analyzation of the currently developed multifunctional nanoparticles, their platform structures with organic or inorganic backbones were systemically generalized. We emphasized on the functionalization and modification strategies, which provide additional functions to the nanoparticle. We also discussed the application combination strategies that were involved in the development of nanoformulations with functional crosstalk. This review thus provides an overview of the construction strategies and application advances of multifunctional nanoparticles.

The role of cell membrane-coated nanoparticles as a novel treatment approach in glioblastoma

Glioblastoma multiform (GBM) is the most prevalent and deadliest primary brain malignancy in adults, whose median survival rate does not exceed 15 months after diagnosis. The conventional treatment of GBM, including maximal safe surgery followed by chemotherapy and radiotherapy, usually cannot lead to notable improvements in the disease prognosis and the tumor always recurs. Many GBM characteristics make its treatment challenging. The most important ones are the impermeability of the blood-brain barrier (BBB), preventing chemotherapeutic drugs from reaching in adequate amounts to the tumor site, intratumoral heterogeneity, and roles of glioblastoma stem cells (GSCs). To overcome these barriers, the recently-developed drug-carrying approach using nanoparticles (NPs) may play a significant role. NPs are tiny particles, usually less than 100 nm showing various diagnostic and therapeutic medical applications. In this regard, cell membrane (CM)-coated NPs demonstrated several promising effects in GBM in pre-clinical studies. They benefit from fewer adverse effects due to their specific targeting of tumor cells, biocompatibility because of their CM surfaces, prolonged half-life, easy penetrating of the BBB, and escaping from the immune reaction, making them an attractive option for GBM treatment. To date, CM-coated NPs have been applied to enhance the effectiveness of major therapeutic approaches in GBM treatment, including chemotherapy, immunotherapy, gene therapy, and photo-based therapies. Despite the promising results in pre-clinical studies regarding the effectiveness of CM-coated NPs in GBM, significant barriers like high expenses, complex preparation processes, and unknown long-term effects still hinder its mass production for the clinic. In this regard, the current study aims to provide an overview of different characteristics of CM-coated NPs and comprehensively investigate their application as a novel treatment approach in GBM.

Targeting drugs to tumours using cell membrane-coated nanoparticles

Traditional cancer therapeutics, such as chemotherapies, are often limited by their non-specific nature, causing harm to non-malignant tissues. Over the past several decades, nanomedicine researchers have sought to address this challenge by developing nanoscale platforms capable of more precisely delivering drug payloads. Cell membrane-coated nanoparticles (CNPs) are an emerging class of nanocarriers that have demonstrated considerable promise for biomedical applications. Consisting of a synthetic nanoparticulate core camouflaged by a layer of naturally derived cell membranes, CNPs are adept at operating within complex biological environments; depending on the type of cell membrane utilized, the resulting biomimetic nanoformulation is conferred with several properties typically associated with the source cell, including improved biocompatibility, immune evasion and tumour targeting. In comparison with traditional functionalization approaches, cell membrane coating provides a streamlined method for creating multifunctional and multi-antigenic nanoparticles. In this Review, we discuss the history and development of CNPs as well as how these platforms have been used for cancer therapy. The application of CNPs for drug delivery, phototherapy and immunotherapy will be described in detail. Translational efforts are currently under way and further research to address key areas of need will ultimately be required to facilitate the successful clinical adoption of CNPs.