Tailoring Particle Size of Mesoporous Silica Nanosystem To Antagonize Glioblastoma and Overcome Blood-Brain Barrier

Nanosystems for targeted drug Delivery: Innovations and challenges in overcoming the Blood-Brain barrier for neurodegenerative disease and cancer therapy

The evolution of sophisticated nanosystems has revolutionized biomedicine, notably in treating neurodegenerative diseases and cancer. These systems show potential in delivering medication precisely to affected tissues, improving treatment effectiveness while minimizing side effects. Nevertheless, a major hurdle in targeted drug delivery is breaching the blood-brain barrier (BBB), a selective shield separating the bloodstream from the brain and spinal cord. The tight junctions between endothelial cells in brain capillaries create a formidable physical barrier, alongside efflux transporters that expel harmful molecules. This presents a notable challenge for brain drug delivery. Nanosystems present distinct advantages in overcoming BBB challenges, offering enhanced drug efficacy, reduced side effects, improved stability, and controlled release. Despite their promise, challenges persist, such as the BBB's regional variability hindering uniform drug distribution. Efflux transporters can also limit therapeutic agent efficacy, while nanosystem toxicity necessitates rigorous safety evaluations. Understanding the long-term impact of nanomaterials on the brain remains crucial. Additionally, addressing nanosystem scalability, cost-effectiveness, and safety profiles is vital for widespread clinical implementation. This review delves into the advancements and obstacles of advanced nanosystems in targeted drug delivery for neurodegenerative diseases and cancer therapy, with a focus on overcoming the BBB.

Mitocytosis Mediated by an Enzyme-Activable Mitochondrion-Disturbing Polymer-Drug Conjugate Enhances Active Penetration in Glioblastoma Therapy

The application of nanomedicines for glioblastoma (GBM) therapy is hampered by the blood-brain barrier (BBB) and the dense glioblastoma tissue. To achieve efficient BBB crossing and deep GBM penetration, this work demonstrates a strategy of active transcellular transport of a mitochondrion-disturbing nanomedicine, pGBEMA22-b-pSSPPT9 (GBEPPT), in the GBM tissue through mitocytosis. GBEPPT is computer-aided designed and prepared by self-assembling a conjugate of an amphiphilic block polymer and a drug podophyllotoxin (PPT). When GBEPPT is delivered to the tumor site, overexpressed γ-glutamyl transpeptidase (GGT) on the brain-blood endothelial cell, or the GBM cell triggered enzymatic hydrolysis of γ-glutamylamide on GBEPPT to reverse its negative charge to positive. Positively charged GBEPPT rapidly enter into the cell and target the mitochondria. These GBEPPT disturb the homeostasis of mitochondria, inducing mitocytosis-mediated extracellular transport of GBEPPT to the neighboring cells via mitosomes. This intracellular-to-intercellular delivery cycle allows GBEPPT to penetrate deeply into the GBM parenchyma, and exert sustainable action of PPT released from GBEPPT on the tumor cells along its penetration path at the tumor site, thus improving the anti-GBM effect. The process of mitocytosis mediated by the mitochondrion-disturbing nanomedicine may offer great potential in enhancing drug penetration through malignant tissues, especially poorly permeable solid tumors.

Overcoming the Blood-Brain Tumor Barrier with Docetaxel-Loaded Mesoporous Silica Nanoparticles for Treatment of Temozolomide-Resistant Glioblastoma

While temozolomide (TMZ) has been a cornerstone in the treatment of newly diagnosed glioblastoma (GBM), a significant challenge has been the emergence of resistance to TMZ, which compromises its clinical benefits. Additionally, the nonspecificity of TMZ can lead to detrimental side effects. Although TMZ is capable of penetrating the blood-brain barrier (BBB), our research addresses the need for targeted therapy to circumvent resistance mechanisms and reduce off-target effects. This study introduces the use of PEGylated mesoporous silica nanoparticles (MSN) with octyl group modifications (C8-MSN) as a nanocarrier system for the delivery of docetaxel (DTX), providing a novel approach for treating TMZ-resistant GBM. Our findings reveal that C8-MSN is biocompatible in vitro, and DTX@C8-MSN shows no hemolytic activity at therapeutic concentrations, maintaining efficacy against GBM cells. Crucially, in vivo imaging demonstrates preferential accumulation of C8-MSN within the tumor region, suggesting enhanced permeability across the blood-brain tumor barrier (BBTB). When administered to orthotopic glioma mouse models, DTX@C8-MSN notably prolongs survival by over 50%, significantly reduces tumor volume, and decreases side effects compared to free DTX, indicating a targeted and effective approach to treatment. The apoptotic pathways activated by DTX@C8-MSN, evidenced by the increased levels of cleaved caspase-3 and PARP, point to a potent therapeutic mechanism. Collectively, the results advocate DTX@C8-MSN as a promising candidate for targeted therapy in TMZ-resistant GBM, optimizing drug delivery and bioavailability to overcome current therapeutic limitations.

Functionalized Nanomaterials Capable of Crossing the Blood-Brain Barrier

The blood-brain barrier (BBB) is a specialized semipermeable structure that highly regulates exchanges between the central nervous system parenchyma and blood vessels. Thus, the BBB also prevents the passage of various forms of therapeutic agents, nanocarriers, and their cargos. Recently, many multidisciplinary studies focus on developing cargo-loaded nanoparticles (NPs) to overcome these challenges, which are emerging as safe and effective vehicles in neurotheranostics. In this Review, first we introduce the anatomical structure and physiological functions of the BBB. Second, we present the endogenous and exogenous transport mechanisms by which NPs cross the BBB. We report various forms of nanomaterials, carriers, and their cargos, with their detailed BBB uptake and permeability characteristics. Third, we describe the effect of regulating the size, shape, charge, and surface ligands of NPs that affect their BBB permeability, which can be exploited to enhance and promote neurotheranostics. We classify typical functionalized nanomaterials developed for BBB crossing. Fourth, we provide a comprehensive review of the recent progress in developing functional polymeric nanomaterials for applications in multimodal bioimaging, therapeutics, and drug delivery. Finally, we conclude by discussing existing challenges, directions, and future perspectives in employing functionalized nanomaterials for BBB crossing.

Silica-based microencapsulation used in topical dermatologic applications

Microencapsulation has received extensive attention because of its various applications. Since its inception in the 1940s, this technology has been used across several areas, including the chemical, food, and pharmaceutical industries. Over-the-counter skin products often contain ingredients that readily and unevenly degrade upon contact with the skin. Enclosing these substances within a silica shell can enhance their stability and better regulate their delivery onto and into the skin. Silica microencapsulation uses silica as the matrix material into which ingredients can be embedded to form microcapsules. The FDA recognizes amorphous silica as a safe inorganic excipient and recently approved two new topical therapies for the treatment of rosacea and acne. The first approved formulation uses a novel silica-based controlled vehicle delivery technology to improve the stability of two active ingredients that are normally not able to be used in the same formulation due to potential instability and drug degradation. The formulation contains 3.0% benzoyl peroxide (BPO) and 0.1% tretinoin topical cream to treat acne vulgaris in adults and pediatric patients. The second formulation contains silica microencapsulated 5.0% BPO topical cream to treat inflammatory rosacea lesions in adults. Both formulations use the same amorphous silica sol-gel microencapsulation technology to improve formulation stability and skin compatibility parameters.

Silica nanoparticles: A review of their safety and current strategies to overcome biological barriers

Silica nanoparticles (SNP) have gained tremendous attention in the recent decades. They have been used in many different biomedical fields including diagnosis, biosensing and drug delivery. Medical uses of SNP for anti-cancer, anti-microbial and theranostic applications are especially prominent due to their exceptional performance to deliver many different small molecules and recently biologics (mRNA, siRNA, antigens, antibodies, proteins, and peptides) at targeted sites. The physical and chemical properties of SNP such as large specific surface area, tuneable particle size and porosity, excellent biodegradability and biocompatibility make them an ideal drug delivery and diagnostic platform. Based on the available data and the pre-clinical performance of SNP, recent interest has driven these innovative materials towards clinical application with many of the formulations already in Phase I and Phase II trials. Herein, the progress of SNP in biomedical field is reviewed, and their safety aspects are analysed. Importantly, we critically evaluate the key structural characteristics of SNP to overcome different biological barriers including the blood-brain barrier (BBB), skin, tumour barrier and mucosal barrier. Future directions, potential pathways, and target areas towards rapid clinical translation of SNP are also recommended.

Nanoparticles Mediated the Diagnosis and Therapy of Glioblastoma: Bypass or Cross the Blood-Brain Barrier

Glioblastoma is one of the most aggressive central nervous system malignancies with high morbidity and mortality. Current clinical approaches, including surgical resection, radiotherapy, and chemotherapy, are limited by the difficulty of targeting brain lesions accurately, leading to disease recurrence and fatal outcomes. The lack of effective treatments has prompted researchers to continuously explore novel therapeutic strategies. In recent years, nanomedicine has made remarkable progress and expanded its application in brain drug delivery, providing a new treatment for brain tumors. Against this background, this article reviews the application and progress of nanomedicine delivery systems in brain tumors. In this paper, the mechanism of nanomaterials crossing the blood-brain barrier is summarized. Furthermore, the specific application of nanotechnology in glioblastoma is discussed in depth.

Intranasal administration of molecular-gated mesoporous nanoparticles to increase ponatinib delivery to the brain

Background: Glioblastoma is the most common and lethal brain cancer. New treatments are needed. However, the presence of the blood-brain barrier is limiting the development of new treatments directed toward the brain, as it restricts the access and distribution of drugs to the CNS. Materials & methods: In this work, two different nanoparticles (i.e., mesoporous silica nanoparticles and magnetic mesoporous silica nanoparticles) loaded with ponatinib were prepared. Results & conclusion: Both particles were characterized and tested in vitro and in vivo, proving that they are not toxic for blood-brain barrier cells and they increase the amount of drug reaching the brain when administered intranasally in comparison with the results obtained for the free drug.

Detachable MOF-Based Core/Shell Nanoreactor for Cancer Dual-Starvation Therapy With Reversing Glucose and Glutamine Metabolisms

Tumor-dependent glucose and glutamine metabolisms are essential for maintaining survival, while the accordingly metabolic suppressive therapy is limited by the compensatory metabolism and inefficient delivery efficiency. Herein, a functional metal-organic framework (MOF)-based nanosystem composed of the weakly acidic tumor microenvironment-activated detachable shell and reactive oxygen species (ROS)-responsive disassembled MOF nanoreactor core is designed to co-load glycolysis and glutamine metabolism inhibitors glucose oxidase (GOD) and bis-2-(5-phenylacetmido-1,2,4-thiadiazol-2-yl) ethyl sulfide (BPTES) for tumor dual-starvation therapy. The nanosystem excitingly improves tumor penetration and cellular uptake efficiency via integrating the pH-responsive size reduction and charge reversal and ROS-sensitive MOF disintegration and drug release strategy. Furthermore, the degradation of MOF and cargoes release can be self-amplified via additional self-generation H2 O2 mediated by GOD. Last, the released GOD and BPTES collaboratively cut off the energy supply of tumors and induce significant mitochondrial damage and cell cycle arrest via simultaneous restriction of glycolysis and compensatory glutamine metabolism pathways, consequently realizing the remarkable triple negative breast cancer killing effect in vivo with good biosafety via the dual starvation therapy.

Virus-like Silica Nanoparticles Improve Permeability of Macromolecules across the Blood-Brain Barrier In Vitro

The presence of the blood-brain barrier (BBB) limits the delivery of therapies into the brain. There has been significant interest in overcoming the BBB for the effective delivery of therapies to the brain. Inorganic nanomaterials, especially silica nanoparticles with varying surface chemistry and surface topology, have been recently used as permeation enhancers for oral protein delivery. In this context, nanoparticles with varying sizes and surface chemistries have been employed to overcome this barrier; however, there is no report examining the effect of nanoscale roughness on BBB permeability. This paper reports the influence of nanoscale surface roughness on the integrity and permeability of the BBB in vitro, using smooth surface Stöber silica nanoparticles (60 nm) compared to rough surface virus-like silica nanoparticles (VSNP, 60 nm). Our findings reveal that VSNP (1 mg/mL) with virus-mimicking-topology spiky surface have a greater effect on transiently opening endothelial tight junctions of the BBB than the same dose of Stöber silica nanoparticles (1 mg/mL) by increasing the FITC-Dextran (70 kDa) permeability 1.9-fold and by decreasing the trans-endothelial electrical resistance (TEER) by 2.7-fold. This proof-of-concept research paves the way for future studies to develop next-generation tailored surface-modified silica nanoparticles, enabling safe and efficient macromolecule transport across the BBB.

Silica nanoparticles for brain cancer

INTRODUCTION

Brain cancer is a debilitating disease with a poor survival rate. There are significant challenges for effective treatment due to the presence of the blood-brain barrier (BBB) and blood-tumor barrier (BTB) which impedes drug delivery to tumor sites. Many nanomedicines have been tested in improving both the survival and quality of life of patients with brain cancer with the recent focus on inorganic nanoparticles such as silica nanoparticles (SNPs). This review examines the use of SNPs as a novel approach for diagnosing, treating, and theranostics of brain cancer.

AREAS COVERED

The review provides an overview of different brain cancers and current therapies available. A special focus on the key functional properties of SNPs is discussed which makes them an attractive material in the field of onco-nanomedicine. Strategies to overcome the BBB using SNPs are analyzed. Furthermore, recent advancements in active targeting, combination therapies, and innovative nanotherapeutics utilizing SNPs are discussed. Safety considerations, toxicity profiles, and regulatory aspects are addressed to provide an understanding of SNPs' translational potential.

EXPERT OPINION

SNPs have tremendous prospects in brain cancer research. The multifunctionality of SNPs has the potential to overcome both the BBB and BTB limitations and can be used for brain cancer imaging, drug delivery, and theranostics. The insights provided will facilitate the development of next-generation, innovative strategies, guiding future research toward improved diagnosis, targeted therapy, and better outcomes in brain cancer patients.

Challenges and advances for glioma therapy based on inorganic nanoparticles

Glioma is one of the most serious central nervous system diseases, with high mortality and poor prognosis. Despite the continuous development of existing treatment methods, the median survival time of glioma patients is still only 15 months. The main treatment difficulties are the invasive growth of glioma and the obstruction of the blood-brain barrier (BBB) to drugs. With rapid advancements in nanotechnology, inorganic nanoparticles (INPs) have shown favourable application prospects in the diagnosis and treatment of glioma. Due to their extraordinary intrinsic features, INPs can be easily fabricated, while doping with other elements and surface modification by biological ligands can be used to enhance BBB penetration, targeted delivery and biocompatibility. Guided glioma theranostics with INPs can improve and enhance the efficacy of traditional methods such as chemotherapy, radiotherapy and gene therapy. New strategies, such as immunotherapy, photothermal and photodynamic therapy, magnetic hyperthermia therapy, and multifunctional inorganic nanoplatforms, have also been facilitated by INPs. This review emphasizes the current state of research and clinical applications of INPs, including glioma targeting and BBB penetration enhancement methods, in vivo and in vitro biocompatibility, and diagnostic and treatment strategies. As such, it provides insights for the development of novel glioma treatment strategies.

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.

Advances in antibody-based drugs and their delivery through the blood-brain barrier for targeted therapy and immunotherapy of gliomas

Gliomas are highly invasive and are the most common type of primary malignant brain tumor. The routine treatments for glioma include surgical resection, radiotherapy, and chemotherapy. However, glioma recurrence and patient survival remain unsatisfactory after employing these traditional treatment approaches. With the rapid development of molecular immunology, significant breakthroughs have been made in targeted glioma therapy and immunotherapy. Antibody-based therapy has excellent advantages in treating gliomas due to its high specificity and sensitivity. This article reviewed various targeted antibody drugs for gliomas, including anti-glioma surface marker antibodies, anti-angiogenesis antibodies, and anti-immunosuppressive signal antibodies. Notably, many antibodies have been validated clinically, such as bevacizumab, cetuximab, panitumumab, and anti-PD-1 antibodies. These antibodies can improve the targeting of glioma therapy, enhance anti-tumor immunity, reduce the proliferation and invasion of glioma, and thus prolong the survival time of patients. However, the existence of the blood-brain barrier (BBB) has caused significant difficulties in drug delivery for gliomas. Therefore, this paper also summarized drug delivery methods through the BBB, including receptor-mediated transportation, nano-based carriers, and some physical and chemical methods for drug delivery. With these exciting advancements, more antibody-based therapies will likely enter clinical practice and allow more successful control of malignant gliomas.

From cells to organoids: The evolution of blood-brain barrier technology for modelling drug delivery in brain cancer

Brain cancer remains the deadliest cancer. The blood-brain barrier (BBB) is impenetrable to most drugs and is a complex 3D network of multiple cell types including endothelial cells, astrocytes, and pericytes. In brain cancers, the BBB becomes disrupted during tumor progression and forms the blood-brain tumor barrier (BBTB). To advance therapeutic development, there is a critical need for physiologically relevant BBB in vitro models. 3D cell systems are emerging as valuable preclinical models to accelerate discoveries for diseases. Given the versatility and capability of 3D cell models, their potential for modelling the BBB and BBTB is reviewed. Technological advances of BBB models and challenges of in vitro modelling the BBTB, and application of these models as tools for assessing therapeutics and nano drug delivery, are discussed. Quantitative, in vitro BBB models that are predictive of effective brain cancer therapies will be invaluable for accelerating advancing new treatments to the clinic.

Diagnostic performance of perfusion-weighted imaging combined with serum MMP-2 and -9 levels in tumor recurrence after postoperative concomitant chemoradiotherapy of glioblastoma

OBJECTIVE

To evaluate diagnostic accuracy of dynamic susceptibility contrast- perfusion weighted imaging (DSC-PWI) combined with serum MMP-2 and -9 levels in differentiating recurrent glioblastoma (GBM).

METHODS

We enrolled a total of 220 GBM patients, including recurrent cases (n = 150) and non-recurrent cases (n = 70) after postoperative concomitant chemoradiotherapy. All patients performed preoperative and follow-up DSC-PWI, and two parameters [normalized cerebral blood volume (nCBV) and cerebral blood flow (nCBF)] were obtained. Preoperative serum levels of MMP-2 and MMP-9 were detected using ELISA. The diagnostic performance was evaluated by analyzing receiver operating characteristic (ROC) and area under the curve (AUC).

RESULTS

At baseline, the recurrence patients had higher nCBF and nCBV than the non-recurrence patients, accompanying by the increased MMP-2 and MMP-9 levels in serum. Serum MMP-2 level were positively associated with MMP-9 in recurrent patients. In patients classified as recurrence, both MMP-9 and MMP-2 in serum had a significant correlation with nCBV and nCBF. A sensitivity and specificity of nCBF for recurrence vs. non-recurrence were 94.29% and 63.33%, respectively. nCBV also could provide high discrimination between recurrence and non-recurrence patients (sensitivity: 84.29%, specificity: 62.67%, AUC: 0.821). In ROC analyses, both MMP-2 and MMP-9 distinguished recurrence from non-recurrence with AUC values of 0.883 and 0.900, respectively. Finally, the combination of DSC-PWI parameters (nCBF and nCBV) and serum MMP-2 and -9 levels showed much better discrimination capacity between recurrence and non-recurrence patients with a sensitivity of 92.86%, specificity of 79.33% and AUC of 0.899.

CONCLUSION

The combination of DSC-PWI parameters together with serum MMP-2 and -9 levels offered an attractive approach to noninvasively distinguish recurrence after postoperative radiotherapy of GBM.

Selenadiazole derivative-loaded metal azolate frameworks facilitate NK cell immunotherapy by sensitizing tumor cells and shaping immuno-suppressive microenvironments

The low sensitivity of tumor cells and immunosuppressive microenvironments lead to unsatisfactory efficacy of natural killer (NK) cell immunotherapy. In this work, we developed a safe and effective combination treatment strategy by integrating a selenadiazole derivative (PSeD)-loaded metal azolate framework (PSeD@MAF-4(R)) with NK cells derived from cancer patients against a xenograft human breast tumor model. Intriguingly, it was found that only PSeD@MAF-4(R) pretreatment on tumor cells exhibited synergistic effects with NK cells in inhibiting tumor cell growth by up-regulating NKG2D and its ligands to maximize the interactions between NK and MCF-7 cells. Moreover, PSeD@MAF-4(R) pretreatment could significantly enhance the degranulation of NK cells and regulate their secretions of pro- or anti-inflammatory cytokines (e.g. IL-6, IL-10, and TGF-β). Furthermore, PSeD@MAF-4(R) could significantly enhance the penetration capability of NK cells into tumor spheroids. The combination treatment mainly induced G1 phase arrest and activated multiple caspase-mediated apoptosis of tumor cells. In vivo evidence showed that PSeD@MAF-4(R) combined with NK cells could highly efficiently combat breast tumor progression via inducing and activating innate immune cell (DC and NK cell) infiltrations within tumor tissues while shaping the suppressive tumor microenvironment by down-regulating the expression of TGF-β. This developed strategy may provide important information for developing NK cell-based combination cancer immunotherapy with high efficacy and good safety profiles.

Advances in Preclinical/Clinical Glioblastoma Treatment: Can Nanoparticles Be of Help?

Glioblastoma multiforme (GB) is the most aggressive and frequent primary malignant tumor in the central nervous system (CNS), with unsatisfactory and challenging treatment nowadays. Current standard of care includes surgical resection followed by chemotherapy and radiotherapy. However, these treatments do not much improve the overall survival of GB patients, which is still below two years (the 5-year survival rate is below 7%). Despite various approaches having been followed to increase the release of anticancer drugs into the brain, few of them demonstrated a significant success, as the blood brain barrier (BBB) still restricts its uptake, thus limiting the therapeutic options. Therefore, enormous efforts are being devoted to the development of novel nanomedicines with the ability to cross the BBB and specifically target the cancer cells. In this context, the use of nanoparticles represents a promising non-invasive route, allowing to evade BBB and reducing systemic concentration of drugs and, hence, side effects. In this review, we revise with a critical view the different families of nanoparticles and approaches followed so far with this aim.

Engineering cancer cell membrane-camouflaged metal complex for efficient targeting therapy of breast cancer

Background

Cancer cell membrane-camouflaged nanotechnology for metal complex can enhance its biocompatibility and extend the effective circulation time in body. The ruthenium polypyridyl complex (RuPOP) has extensive antitumor activity, but it still has disadvantages such as poor biocompatibility, lack of targeting, and being easily metabolized by the organism. Cancer cell membranes retain a large number of surface antigens and tumor adhesion molecules CD47, which can be used to camouflage the metal complex and give it tumor homing ability and high biocompatibility.

Results

Therefore, this study provides an electrostatic adsorption method, which uses the electrostatic interaction of positive and negative charges between RuPOP and cell membranes to construct a cancer cell membrane-camouflaged nano-platform (RuPOP@CM). Interestingly, RuPOP@CM maintains the expression of surface antigens and tumor adhesion molecules, which can inhibit the phagocytosis of macrophage, reduce the clearance rate of RuPOP, and increase effective circulation time, thus enhancing the accumulation in tumor sites. Besides, RuPOP@CM can enhance the activity of cellular immune response and promote the production of inflammatory cytokines including TNF-α, IL-12 and IL-6, which is of great significance in treatment of tumor. On the other hand, RuPOP@MCM can produce intracellular ROS overproduction, thereby accelerating the apoptosis and cell cycle arrest of tumor cells to play an excellent antitumor effect in vitro and in vivo.

Conclusion

In brief, engineering cancer cell membrane-camouflaged metal complex is a potential strategy to improve its biocompatibility, biological safety and antitumor effects.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01593-5.

Nanotherapeutic treatment of the invasive glioblastoma tumor microenvironment

Glioblastoma (GBM) is the most common malignant adult brain cancer with no curative treatment strategy. A significant hurdle in GBM treatment is effective therapeutic delivery to the brain-invading tumor cells that remain following surgery within functioning brain regions. Developing therapies that can either directly target these brain-invading tumor cells or act on other cell types and molecular processes supporting tumor cell invasion and recurrence are essential steps in advancing new treatments in the clinic. This review highlights some of the drug delivery strategies and nanotherapeutic technologies that are designed to target brain-invading GBM cells or non-neoplastic, invasion-supporting cells residing within the GBM tumor microenvironment.

Engineering mesoporous silica nanoparticles for drug delivery: where are we after two decades?

The present review details a chronological description of the events that took place during the development of mesoporous materials, their different synthetic routes and their use as drug delivery systems. The outstanding textural properties of these materials quickly inspired their translation to the nanoscale dimension leading to mesoporous silica nanoparticles (MSNs). The different aspects of introducing pharmaceutical agents into the pores of these nanocarriers, together with their possible biodistribution and clearance routes, would be described here. The development of smart nanocarriers that are able to release a high local concentration of the therapeutic cargo on-demand after the application of certain stimuli would be reviewed here, together with their ability to deliver the therapeutic cargo to precise locations in the body. The huge progress in the design and development of MSNs for biomedical applications, including the potential treatment of different diseases, during the last 20 years will be collated here, together with the required work that still needs to be done to achieve the clinical translation of these materials. This review was conceived to stand out from past reports since it aims to tell the story of the development of mesoporous materials and their use as drug delivery systems by some of the story makers, who could be considered to be among the pioneers in this area.

Silica nanoparticles: Biomedical applications and toxicity

Silica nanoparticles (SiNPs) are composed of silicon dioxide, the most abundant compound on Earth, and are used widely in many applications including the food industry, synthetic processes, medical diagnosis, and drug delivery due to their controllable particle size, large surface area, and great biocompatibility. Building on basic synthetic methods, convenient and economical strategies have been developed for the synthesis of SiNPs. Numerous studies have assessed the biomedical applications of SiNPs, including the surface and structural modification of SiNPs to target various cancers and diagnose diseases. However, studies on the in vitro and in vivo toxicity of SiNPs remain in the exploratory stage, and the toxicity mechanisms of SiNPs are poorly understood. This review covers recent studies on the biomedical applications of SiNPs, including their uses in drug delivery systems to diagnose and treat various diseases in the human body. SiNP toxicity is discussed in terms of the different systems of the human body and the individual organs in those systems. This comprehensive review includes both fundamental discoveries and exploratory progress in SiNP research that may lead to practical developments in the future.

Nanomedicine for Glioblastoma: Progress and Future Prospects

Glioblastoma is the most aggressive form of brain tumor, accounting for the highest mortality and morbidity rates. Current treatment for patients with glioblastoma includes maximal safe tumor resection followed by radiation therapy with concomitant temozolomide (TMZ) chemotherapy. The addition of TMZ to the conformal radiation therapy has improved the median survival time only from 12 months to 16 months in patients with glioblastoma. Despite these aggressive treatment strategies, patients' prognosis remains poor. This therapeutic failure is primarily attributed to the blood-brain barrier (BBB) that restricts the transport of TMZ from reaching the tumor site. In recent years, nanomedicine has gained considerable attention among researchers and shown promising developments in clinical applications, including the diagnosis, prognosis, and treatment of glioblastoma tumors. This review sheds light on the morphological and physiological complexity of the BBB. It also explains the development of nanomedicine strategies to enhance the permeability of drug molecules across the BBB.

Bimetallic gold-platinum nanoparticles as a drug delivery system coated with a new drug to target glioblastoma

A drug delivery nanosystem of noble bimetallic nanoparticles (NPs) which consists of Au NPs capped with Pt NPs (Au@Pt NPs) is constructed and functionalised with a quinazoline based small molecule (Au@Pt@Q NPs), acting as a theranostic agent against glioblastoma. Two different hydrothermal synthetic procedures for bimetallic Au@Pt NPs are presented and the resulting nanostructures are fully characterised by means of spectroscopic and microscopic methods. The imaging and targeting capacity of the new drug delivery system is assessed through fluorescent optical microscopy and cytotoxicity evaluations. The constructed Au@Pt NPs consist a monodispersed colloidal solution of 25 nm with photoluminescent, fluorescent and X-Ray absorption properties that confirm their diagnostic potential. Haemolysis testing demonstrated that Au@Pt NPs are biocompatible and fluorescent microscopy confirmed their entering the cells. Cytological evaluation of the NPs through MTT assay showed that they do not inhibit the proliferation of control cell line HEK293, whereas they are toxic in U87MG, U251 and D54 glioblastoma cell lines; rendering them selective targeting agents for treating glioblastoma.

Combinatorial therapeutic strategies for enhanced delivery of therapeutics to brain cancer cells through nanocarriers: current trends and future perspectives

Brain cancer is the most aggressive one among various cancers. It has a drastic impact on people's lives because of the failure in treatment efficacy of the currently employed strategies. Various strategies used to relieve pain in brain cancer patients and to prolong survival time include radiotherapy, chemotherapy, and surgery. Nevertheless, several inevitable limitations are accompanied by such treatments due to unsatisfactory curative effects. Generally, the treatment of cancers is very challenging due to many reasons including drugs’ intrinsic factors and physiological barriers. Blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCSFB) are the two additional hurdles in the way of therapeutic agents to brain tumors delivery. Combinatorial and targeted therapies specifically in cancer show a very promising role where nanocarriers’ based formulations are designed primarily to achieve tumor-specific drug release. A dual-targeting strategy is a versatile way of chemotherapeutics delivery to brain tumors that gets the aid of combined ligands and mediators that cross the BBB and reaches the target site efficiently. In contrast to single targeting where one receptor or mediator is targeted, the dual-targeting strategy is expected to produce a multiple-fold increase in therapeutic efficacy for cancer therapy, especially in brain tumors. In a nutshell, a dual-targeting strategy for brain tumors enhances the delivery efficiency of chemotherapeutic agents via penetration across the blood-brain barrier and enhances the targeting of tumor cells. This review article highlights the ongoing status of the brain tumor therapy enhanced by nanoparticle based delivery with the aid of dual-targeting strategies. The future perspectives in this regard have also been highlighted.

Recent progress in the applications of silica-based nanoparticles

Functionalized silica nanoparticles (SiO2 NPs) have attracted great attention due to their promising distinctive, versatile, and privileged physiochemical characteristics. These enhanced properties make this type of functionalized nanoparticles particularly appropriate for different applications. A lack of reviews that summarizes the fabrications of such nanomaterials and their different applications in the same work has been observed in the literature. Therefore, in this work, we will discuss the recent signs of progress in the fabrication of functionalized silica nanoparticles and their attractive applications that have been extensively highlighted (advanced catalysis, drug-delivery, biomedical applications, environmental remediation applications, and wastewater treatment). These applications have been selected for demonstrating the role of the surface modification step on the various properties of the silica surface. In addition, the current challenges in the applications of functionalized silica nanoparticles and corresponding strategies to discuss these issues and future perspectives for additional improvement have been addressed.

A Gambogic Acid-Loaded Delivery System Mediated by Ultrasound-Targeted Microbubble Destruction: A Promising Therapy Method for Malignant Cerebral Glioma

Background

Purpose

Methods

Results

Conclusion

Cell penetrating peptide decorated magnetic porous silicon nanorods for glioblastoma therapy and imaging

Glioblastoma multiforme (GBM) is the most malignant primary brain tumor of the central nervous system. Despite advances in therapy, it remains largely untreatable, in part due to the low permeability of chemotherapeutic drugs across the blood-brain barrier (BBB) which significantly compromises their effectiveness. To circumvent the lack of drug efficiency, we designed multifunctional nanoparticles based on porous silicon. Herein, we propose an innovative synthesis technique for porous silicon nanorods (pSiNRs) with three-dimensional (3D) shape-controlled nanostructure. In order to achieve an efficient administration and improved treatment against GBM cells, a porous silicon nanoplatform is designed with magnetic guidance, fluorescence tracking and a cell-penetrating peptide (CPP). A NeuroFilament Light (NFL) subunit derived 24 amino acid tubulin binding site peptide called NFL-TBS.40-63 peptide or NFL-peptide was reported to preferentially target human GBM cells compared to healthy cells. Motivated by this approach, we investigated the use of magnetic-pSiNRs covered with superparamagnetic iron oxide nanoparticles (SPIONs) for magnetic guidance, then decorated with the NFL-peptide to facilitate targeting and enhance internalization into human GBM cells. Unexpectedly, under confocal microscope imaging, the internalized multifunctional nanoparticles in GBM cells induce a remarkable exaltation of green fluorescence instead of the red native fluorescence from the dye due to a possible Förster resonance energy transfer (FRET). In addition, we showed that the uptake of NFL-peptide decorated magnetic-pSiNRs was preferential towards human GBM cells. This study presents the fabrication of magnetic-pSiNRs decorated with the NFL-peptide, which act as a remarkable candidate to treat brain tumors. This is supported by in vitro results and confocal imaging.

Enhanced Antioxidant Effects of the Anti-Inflammatory Compound Probucol when Released from Mesoporous Silica Particles

Brain endothelial cells mediate the function and integrity of the blood brain barrier (BBB) by restricting its permeability and exposure to potential toxins. However, these cells are highly susceptible to cellular damage caused by oxidative stress and inflammation. Consequent disruption to the integrity of the BBB can lead to the pathogenesis of neurodegenerative diseases. Drug compounds with antioxidant and/or anti-inflammatory properties therefore have the potential to preserve the structure and function of the BBB. In this work, we demonstrate the enhanced antioxidative effects of the compound probucol when loaded within mesoporous silica particles (MSP) in vitro and in vivo zebrafish models. The dissolution kinetics were significantly enhanced when released from MSPs. An increased reduction in lipopolysaccharide (LPS)-induced reactive oxygen species (ROS), cyclooxygenase (COX) enzyme activity and prostaglandin E₂ production was measured in human brain endothelial cells treated with probucol-loaded MSPs. Furthermore, the LPS-induced permeability across an endothelial cell monolayer by paracellular and transcytotic mechanisms was also reduced at lower concentrations compared to the antioxidant ascorbic acid. Zebrafish pre-treated with probucol-loaded MSPs reduced hydrogen peroxide-induced ROS to control levels after 24-h incubation, at significantly lower concentrations than ascorbic acid. We provide compelling evidence that the encapsulation of antioxidant and anti-inflammatory compounds within MSPs can enhance their release, enhance their antioxidant effects properties, and open new avenues for the accelerated suppression of neuroinflammation.

Local Delivery and Glioblastoma: Why Not Combining Sustained Release and Targeting?

Glioblastoma is one of the most aggressive brain tumors and is associated with a very low overall median survival despite the current treatment. The standard of care used in clinic is the Stupp's protocol which consists of a maximal resection of the tumor when possible, followed by radio and chemotherapy using temozolomide. However, in most cases, glioblastoma cells infiltrate healthy tissues and lead to fatal recurrences. There are a lot of hurdles to overcome in the development of new therapeutic strategies such as tumor heterogeneity, cell infiltration, alkylating agent resistance, physiological barriers, etc., and few treatments are on the market today. One of them is particularly appealing because it is a local therapy, which does not bring additional invasiveness since tumor resection is included in the gold standard treatment. They are implants: the Gliadel^® wafers, which are deposited post-surgery. Nevertheless, in addition to presenting important undesirable effects, it does not bring any major benefit in the therapy despite the strategy being particularly attractive. The purpose of this review is to provide an overview of recent advances in the development of innovative therapeutic strategies for glioblastoma using an implant-type approach. The combination of this local strategy with effective targeting of the tumor microenvironment as a whole, also developed in this review, may be of interest to alleviate some of the obstacles encountered in the treatment of glioblastoma.

Polysorbate-coated mesoporous silica nanoparticles as an efficient carrier for improved rivastigmine brain delivery

Targeted delivery of neurological therapeutic to the brain has been attracting more and more attention to the treatment of central nervous system (CNS) diseases. Nonetheless, the main obstacle in this road map is the existence of a blood-brain barrier (BBB) which limits the penetration efficiency of most CNS drugs into the brain parenchyma. This present investigation describes a facile synthetic strategy to prepare a highly biocompatible calcium-doped mesoporous silica nanoparticles (MSNs) functionalized by polysorbate-80 (PS) as targeting ligand to deliver rivastigmine (RV) into the brain via crossing the BBB. The developed nanosystem was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), Zeta potential, and N₂-adsorption-desorption analysis. In vitro hemolysis studies were carried out to confirm the biocompatibility of the nanocarriers. Our in vivo studies in an animal model of rats showed that the RV-loaded nanosystem was able to enhance the brain-to-plasma concentration ratio, brain uptake clearance, and plasma elimination half-life of the drug compared to the free one drug following intravenous (IV) administration. The results revealed that functionalization of MSNs by PS is crucial to deliver RV into the brain, suggesting PS-functionalized MSNs could be an effective carrier to deliver RV to the brain while overcoming BBB.

Mesoporous Silica Nanoparticles-Embedded Lanthanide Organic Polyhedra for Enhanced Stability, Luminescence and Cell Imaging

We report here a simple but efficient “ship-in-a-bottle” synthetic strategy for increasing the stability and luminescence performance of LOPs by embedding them into mesoporous silica nanoparticles (MSNs). Three types of...

A novel hypocrellin-based assembly for sonodynamic therapy against glioblastoma

The non-invasive treatment of glioblastoma (GBM) is of great significance and can greatly reduce the complications of craniotomy. Sonodynamic therapy (SDT) is an emerging tumor therapeutic strategy that overcomes some fatal flaws of photodynamic therapy (PDT). Different from PDT, SDT has deep tissue penetration and can be applied in the non-invasive treatment of deep-seated tumors. However, effective sonosensitizers that can be used for SDT of GBM are still very rare. Herein, we have prepared a suitable assembly based on a hypocrellin derivative (CTHB) with good biocompatibility. Excitedly, the hypocrellin-based assembly (CTHB NPs) can effectively produce reactive oxygen species under ultrasound stimulation. The inherent fluorescence and photoacoustic imaging characteristics of the CTHB NPs are conducive to the precise positioning of the tumors. It has been proved both in subcutaneous and in intracranial tumor models that CTHB NPs can be used as an effective sonosensitizer to inhibit tumor growth under ultrasound irradiation. This hypocrellin-based assembly has a good clinical prospect in the non-invasive treatment of GBM.

Facile synthesis of lactoferrin conjugated ultra small large pore silica nanoparticles for the treatment of glioblastoma

The blood brain barrier (BBB) and blood tumour barrier (BTB) remain a major roadblock for delivering therapies to treat brain cancer. Amongst brain cancers, glioblastoma (GBM) is notoriously difficult to treat due to the challenge of delivering chemotherapeutic drugs across the BBB and into the tumour microenvironment. Consequently, GBM has high rates of tumour recurrence. Currently, limited numbers of chemotherapies are available that can cross the BBB to treat GBM. Nanomedicine is an attractive solution for treating GBM as it can augment drug penetration across the BBB and into the heterogeneous tumour site. However, very few nanomedicines exist that can easily overcome both the BBB and BTB owing to difficulty in synthesizing nanoparticles that meet the small size and surface functionality restrictions. In this study, we have developed for the first-time, a room temperature protocol to synthesise ultra-small size with large pore silica nanoparticles (USLP, size ∼30 nm, pore size >7 nm) with the ability to load high concentrations of chemotherapeutic drugs and conjugate a targeting moiety to their surface. The nanoparticles were conjugated with lactoferrin (>80 kDa), whose receptors are overexpressed by both the BBB and GBM, to achieve additional active targeting. Lactoferrin conjugated USLP (USLP-Lf) were loaded with doxorubicin - a chemotherapy agent that is known to be highly effective against GBM in vitro but cannot permeate the BBB. USLP-Lf were able to selectively permeate the BBB in vitro, and were effectively taken up by glioblastoma U87 cells. When compared to the uncoated USLP-NPs, the coating with lactoferrin significantly improved penetration of USLP into U87 tumour spheroids (after 12 hours at 100 μm distance, RFU value 19.58 vs. 49.16 respectively). Moreover, this USLP-Lf based delivery platform improved the efficacy of doxorubicin-mediated apoptosis of GBM cells in both 2D and 3D models. Collectively, our new nano-platform has the potential to overcome both the BBB and BTB to treat GBM more effectively.

Safety Evaluation of Nanotechnology Products

Nanomaterials are now being used in a wide variety of biomedical applications. Medical and health-related issues, however, have raised major concerns, in view of the potential risks of these materials against tissue, cells, and/or organs and these are still poorly understood. These particles are able to interact with the body in countless ways, and they can cause unexpected and hazardous toxicities, especially at cellular levels. Therefore, undertaking in vitro and in vivo experiments is vital to establish their toxicity with natural tissues. In this review, we discuss the underlying mechanisms of nanotoxicity and provide an overview on in vitro characterizations and cytotoxicity assays, as well as in vivo studies that emphasize blood circulation and the in vivo fate of nanomaterials. Our focus is on understanding the role that the physicochemical properties of nanomaterials play in determining their toxicity.

pH and charge reversal-driven nanoplatform for efficient delivery of therapeutics

Nanomedicine which delivers therapeutics to tumours holds great potential for cancer treatment. However, endosomal trapping and uncontrollable release usually limit the efficiency of nanomedicine. Herein, a smart mesoporous silica based nanoplatform was constructed, in which mesoporous silica nanoparticles (MSNs) serve as the core, capped with pH-induced charge-reversal polymer -PAH-cit- and cationic polyelectrolyte polyethyleneimine (PEI). The oppositely charged polymer can not only act as a gatekeeper for controlled release, but also mediated efficient endosomal escape of the therapeutics. Under the acidic endosomal environment, the hydrolysis of acid-cleavable bonds in PAH-Cit would trigger the charge reversal and endosomal escape of the nanoplatform for efficient drug release. Furthermore, the prepared nanoplatform demonstrated a higher tumor cell proliferation inhibition rate than free theruputics in vitro assays and significantly inhibited tumour growth in the 4T1 tumour model in mice. Therefore, our strategy offers a simple and general nanoplatform to delivery therapeutics to tumours with efficient endosomal escape and controlled release.

Biomimetic and cell-based nanocarriers - New strategies for brain tumor targeting

In the last two decades no significant advances were achieved in the treatment of the most frequent and malignant types of brain tumors. The main difficulties in achieving progress are related to the incapacity to deliver drugs in therapeutic amounts into the central nervous system and the associated severe side effects. Indeed, to obtain effective treatments, the drugs should be able to cross the intended biological barriers and not being inactivated before reaching the specific therapeutic target. To overcome these challenges the development of synthetic nanocarriers has been widely explored for brain tumor treatment but unfortunately with no clinical translation until date. The use of cell-derived nanocarriers or biomimetic nanocarriers has been studied in the last few years, considering their innate bio-interfacing properties. The ability to carry therapeutic agents and a higher selectivity towards brain tumors would bring new hope for the development of safe and effective treatments. In this review, we explore the biological barriers that need to be crossed for effective delivery in brain tumors, and the types and properties of cell-based nanocarriers (extracellular vesicles and cell-membrane coated nanocarriers) currently under investigation.

Advanced mesoporous silica nanocarriers in cancer theranostics and gene editing applications

Targeted nanomaterials for cancer theranostics have been the subject of an expanding volume of research studies in recent years. Mesoporous silica nanoparticles (MSNs) are particularly attractive for such applications due to possibilities to synthesize nanoparticles (NPs) of different morphologies, pore diameters and pore arrangements, large surface areas and various options for surface functionalization. Functionalization of MSNs with different organic and inorganic molecules, polymers, surface-attachment of other NPs, loading and entrapping cargo molecules with on-desire release capabilities, lead to seemingly endless prospects for designing advanced nanoconstructs exerting multiple functions, such as simultaneous cancer-targeting, imaging and therapy. Describing composition and multifunctional capabilities of these advanced nanoassemblies for targeted therapy (passive, ligand-functionalized MSNs, stimuli-responsive therapy), including one or more modalities for imaging of tumors, is the subject of this review article, along with an overview of developments within a novel and attractive research trend, comprising the use of MSNs for CRISPR/Cas9 systems delivery and gene editing in cancer. Such advanced nanconstructs exhibit high potential for applications in image-guided therapies and the development of personalized cancer treatment.

Remodelling and Treatment of the Blood-Brain Barrier in Glioma

The blood-brain barrier (BBB) is an essential structure of the central nervous system (CNS), and its existence makes the local internal environment of the CNS a relatively independent structure distinct from other internal environments of the human body to ensure normal physiological and high stability of activities of the CNS. Changes in BBB structure and function are fundamental to the pathophysiology of many diseases. The occurrence and development of glioma are often accompanied by a series of changes in the structure and function of the internal environment, the most significant of which is remodelling of the BBB. The remodelling of the BBB usually leads to changes in the permeability of local microvessels, which provide certain favourable conditions for the occurrence and development of glioma. Meanwhile, the newly generated abnormal blood vessels and the remaining intact regions of the BBB also hinder the effects of drug treatments. Changes in permeability and structural function often lead to the creation of abnormally functioning vascular regions, which pose further treatment challenges. At present, therapeutic methods for glioma have not achieved satisfactory effects in clinical practice, and emerging therapeutic methods have not yet been widely used in clinical practice. In this review, we summarize the knowledge of remodelling of the BBB in the glioma environment, the type of changes that occur, and current BBB treatment methods and prospects for the treatment of glioma.

Selenium-driven enhancement of synergistic cancer chemo-/radiotherapy by targeting nanotherapeutics

To overcome drug resistance in hypoxic tumors and the limitations of radiation impedance and radiation dose, we developed a nano-radiosensitizer to improve the efficacy of cancer radiotherapy. We used multifunctional mesoporous silica nanoparticles (MSNs) as the carriers for a novel anticancer selenadiazole derivative (SeD) and modified its surface with folic acid (FA) to enhance its cervical cancer-targeting effects, forming the nanosystem named SeD@MSNs-FA. Upon radiation, SeD@MSNs-FA inhibits the growth of cervical cancer cells by inducing apoptosis through the death receptor-mediated apoptosis pathway and S phase arrest, significantly improving the sensitivity of cervical cancer cells to X-ray radiation. The combined activity of SeD@MSN-FA and radiation can promote excessive production of intracellular reactive oxygen species (ROS) and induce cell apoptosis by affecting p53, protein kinase B (AKT), and mitogen-activated protein kinase (MAPK) pathways. Furthermore, SeD@MSNs-FA can effectively inhibit tumor growth of xenografted HeLa tumors in nude mice. The toxicity analysis of SeD@MSNs-FA nanoparticles in vivo and the histological analysis performed in the mouse model showed that under the current experimental conditions, the nanoparticles induced no significant damage to the heart, liver, spleen, lungs, kidneys, or other major organs. Taken together, this study provides a translational nanomedicine-based strategy for the simultaneous chemo- and radiotherapy of cervical cancer and sheds light on potential mechanisms that can be used to overcome radiotherapeutic resistance.

Dithiocarbazate-Copper Complexes for Bioimaging and Treatment of Pancreatic Cancer

Anticancer agents that present nonapoptotic cell death pathways are required for treating apoptosis-resistant pancreatic cancer. Here, we synthesized three fluorescent dithiocarbazate-copper complexes, {[Cu^II(L)(Cl)] 1, [Cu^II₂(L)₂(NO₃)₂] 2, and [Cu^II₂Cu^I(L)₂(Br)₃] 3}, to assess their antipancreatic cancer activities. Complexes 1-3 showed significantly greater cytotoxicity toward several pancreatic cancer cell lines with better IC₅₀ than those of the HL ligand and cisplatin. Confocal fluorescence imaging showed that complex 3 was primarily localized in the mitochondria. Primarily, compound 3 also can be applied to in vivo imaging. Further studies revealed that complex 3 kills pancreatic cancer cells by triggering multiple mechanisms, including ferroptosis. Complex 3 is the first copper complex to evoke cellular events consistent with ferroptosis in cancer cells. Finally, it significantly retarded the ASPC-1 cells' growth in a mouse xenograft model.

Frontiers in the treatment of glioblastoma: Past, present and emerging

Glioblastoma (GBM) is one of the most aggressive cancers of the brain. Despite extensive research over the last several decades, the survival rates for GBM have not improved and prognosis remains poor. To date, only a few therapies are approved for the treatment of GBM with the main reasons being: 1) significant tumour heterogeneity which promotes the selection of resistant subpopulations 2) GBM induced immunosuppression and 3) fortified location of the tumour in the brain which hinders the delivery of therapeutics. Existing therapies for GBM such as radiotherapy, surgery and chemotherapy have been unable to reach the clinical efficacy necessary to prolong patient survival more than a few months. This comprehensive review evaluates the current and emerging therapies including those in clinical trials that may potentially improve both targeted delivery of therapeutics directly to the tumour site and the development of agents that may specifically target GBM. Particular focus has also been given to emerging delivery technologies such as focused ultrasound, cellular delivery systems nanomedicines and immunotherapy. Finally, we discuss the importance of developing novel materials for improved delivery efficacy of nanoparticles and therapeutics to reduce the suffering of GBM patients.

Nano-Neurotheranostics: Impact of Nanoparticles on Neural Dysfunctions and Strategies to Reduce Toxicity for Improved Efficacy

Nanotheranostics is one of the emerging research areas in the field of nanobiotechnology offering exciting promises for diagnosis, bio-separation, imaging mechanisms, hyperthermia, phototherapy, chemotherapy, drug delivery, gene delivery, among other uses. The major criteria for any nanotheranostic-materials is 1) to interact with proteins and cells without meddling with their basic activities, 2) to maintain their physical properties after surface modifications and 3) must be nontoxic. One of the challenging targets for nanotheranostics is the nervous system with major hindrances from the neurovascular units, the functional units of blood-brain barrier. As blood-brain barrier is crucial for protecting the CNS from toxins and metabolic fluctuations, most of the synthetic nanomaterials cannot pass through this barrier making it difficult for diagnosing or targeting the cells. Biodegradable nanoparticles show a promising role in this aspect. Certain neural pathologies have compromised barrier creating a path for most of the nanoparticles to enter into the cells. However, such carriers may pose a risk of side effects to non-neural tissues and their toxicity needs to be elucidated at preclinical levels. This article reviews about the different types of nanotheranostic strategies applied in nervous dysfunctions. Further, the side effects of these carriers are reviewed and appropriate methods to test the toxicity of such nano-carriers are suggested to improve the effectiveness of nano-carrier based diagnosis and treatments.

Advances in regulating physicochemical properties of mesoporous silica nanocarriers to overcome biological barriers

Mesoporous silica nanoparticles (MSNs) with remarkable structural features have been proven to be an excellent platform for the delivery of therapeutic molecules. Biological barriers in various forms (e.g., mucosal barrier, cellular barrier, gastrointestinal barrier, blood-brain barrier, and blood-tumor barrier) present substantial obstacles for MSNs. The physicochemical parameters of MSNs are known to be effective and tunable not only for load and release of therapeutic molecules but also for their biological responsiveness that is beneficial for cells and tissues. This review innovatively provides a description of how and why physicochemical properties (e.g., particle size, morphology, surface charge, hydrophilic-hydrophobic property, and surface modification) of MSNs influence their ability to cross the biological barriers prior to reaching targeted sites. First, the structural and physiological features of biological barriers are outlined. Next, the recent progresses in the critical physicochemical parameters of MSNs are highlighted from physicochemical and biological aspects. Surface modification, as an important strategy for achieving rapid transport, is also reviewed with special attention to the latest findings of bioactive groups and molecular mechanisms. Furthermore, advanced designs of multifunction intelligent MSNs to surmount the blood-tumor barrier and to actively target tumor sites are demonstrated in detail. Lastly, the biodegradability and toxicity of MSNs are evaluated. With perspectives for their potential application and biosafety, the clues in summary might lead to drug delivery with high efficiency and provide useful knowledge for rational design of nanomaterials.