The potential of polymeric micelles in the context of glioblastoma therapy

Functionalized liposomes: an enticing nanocarrier for management of glioma

Glioma is one of the most severe central nervous systems (CNS)-specific tumors, with rapidly growing malignant glial cells accounting for roughly half of all brain tumors and having a poor survival rate ranging from 12 to 15 months. Despite being the most often used technique for glioma therapy, conventional chemotherapy suffers from low permeability of the blood-brain barrier (BBB) and blood-brain tumor barrier (BBTB) to anticancer drugs. When it comes to nanocarriers, liposomes are thought of as one of the most promising nanocarrier systems for glioma treatment. However, owing to BBB tight junctions, non-targeted liposomes, which passively accumulate in most cancer cells primarily via the increased permeability and retention effect (EPR), would not be suitable for glioma treatment. The surface modification of liposomes with various active targeting ligands has shown encouraging outcomes in the recent times by allowing various chemotherapy drugs to pass across the BBB and BBTB and enter glioma cells. This review article introduces by briefly outlining the landscape of glioma, its classification, and some of the pathogenic causes. Further, it discusses major barriers for delivering drugs to glioma such as the BBB, BBTB, and tumor microenvironment. It further discusses modified liposomes such as long-acting circulating liposomes, actively targeted liposomes, stimuli responsive liposomes. Finally, it highlighted the limitations of liposomes in the treatment of glioma and the various actively targeted liposomes undergoing clinical trials for the treatment of glioma.

Improving the Treatment Effect of Carotenoids on Alzheimer's Disease through Various Nano-Delivery Systems

Natural bioactive compounds have recently emerged as a current strategy for Alzheimer's disease treatment. Carotenoids, including astaxanthin, lycopene, lutein, fucoxanthin, crocin and others are natural pigments and antioxidants, and can be used to treat a variety of diseases, including Alzheimer's disease. However, carotenoids, as oil-soluble substances with additional unsaturated groups, suffer from low solubility, poor stability and poor bioavailability. Therefore, the preparation of various nano-drug delivery systems from carotenoids is a current measure to achieve efficient application of carotenoids. Different carotenoid delivery systems can improve the solubility, stability, permeability and bioavailability of carotenoids to a certain extent to achieve Alzheimer's disease efficacy. This review summarizes recent data on different carotenoid nano-drug delivery systems for the treatment of Alzheimer's disease, including polymer, lipid, inorganic and hybrid nano-drug delivery systems. These drug delivery systems have been shown to have a beneficial therapeutic effect on Alzheimer's disease to a certain extent.

Exploring the Application of Micellar Drug Delivery Systems in Cancer Nanomedicine

Various formulations of polymeric micelles, tiny spherical structures made of polymeric materials, are currently being investigated in preclinical and clinical settings for their potential as nanomedicines. They target specific tissues and prolong circulation in the body, making them promising cancer treatment options. This review focuses on the different types of polymeric materials available to synthesize micelles, as well as the different ways that micelles can be tailored to be responsive to different stimuli. The selection of stimuli-sensitive polymers used in micelle preparation is based on the specific conditions found in the tumor microenvironment. Additionally, clinical trends in using micelles to treat cancer are presented, including what happens to micelles after they are administered. Finally, various cancer drug delivery applications involving micelles are discussed along with their regulatory aspects and future outlooks. As part of this discussion, we will examine current research and development in this field. The challenges and barriers they may have to overcome before they can be widely adopted in clinics will also be discussed.

Intrinsically Disordered Protein Micelles as Vehicles for Convection-Enhanced Drug Delivery to Glioblastoma Multiforme

Lipid and micelle-based nanocarriers have been explored for anticancer drug delivery to improve accumulation and uptake in tumor tissue. As an experimental opportunity in this area, our lab has developed a protein-based micelle nanocarrier consisting of a hydrophilic intrinsically disordered protein (IDP) domain bound to a hydrophobic tail, termed IDP-2Yx2A. This construct can be used to encapsulate hydrophobic chemotherapeutics that would otherwise be too insoluble in water to be administered. In this study, we evaluate the in vivo efficacy of IDP-2Yx2A by delivering a highly potent but water-insoluble cancer drug, SN38, into glioblastoma multiforme (GBM) tumors via convection-enhanced delivery (CED). The protein carriers alone are shown to elicit minimal toxicity effects in mice; furthermore, they can encapsulate and deliver concentrations of SN38 that would otherwise be lethal without the carriers. CED administration of these drug-loaded micelles into mice bearing U251-MG GBM xenografts resulted in slowed tumor growth and significant increases in median survival times compared to nonencapsulated SN38 and PBS controls.

Micelles as potential drug delivery systems for colorectal cancer treatment

Despite the significant progress in cancer therapy, colorectal cancer (CRC) remains one of the most fatal malignancies worldwide. Chemotherapy is currently the mainstay therapeutic modality adopted for CRC treatment. However, the long-term effectiveness of chemotherapeutic drugs has been hampered by their low bioavailability, non-selective tumor targeting mechanisms, non-specific biodistribution associated with low drug concentrations at the tumor site and undesirable side effects. Over the last decade, there has been increasing interest in using nanotechnology-based drug delivery systems to circumvent these limitations. Various nanoparticles have been developed for delivering chemotherapeutic drugs among which polymeric micelles are attractive candidates. Polymeric micelles are biocompatible nanocarriers that can bypass the biological barriers and preferentially accumulate in tumors via the enhanced permeability and retention effect. They can be easily engineered with stimuli-responsive and tumor targeting moieties to further ensure their selective uptake by cancer cells and controlled drug release at the desirable tumor site. They have been shown to effectively improve the pharmacokinetic properties of chemotherapeutic drugs and enhance their safety profile and anticancer efficacy in different types of cancer. Given that combination therapy is the new strategy implemented in cancer therapy, polymeric micelles are suitable for multidrug delivery and allow drugs to act concurrently at the action site to achieve synergistic therapeutic outcomes. They also allow the delivery of anticancer genetic material along with chemotherapy drugs offering a novel approach for CRC therapy. Here, we highlight the properties of polymeric micelles that make them promising drug delivery systems for CRC treatment. We also review their application in CRC chemotherapy and gene therapy as well as in combination cancer chemotherapy.

Drug Delivery Systems in the Development of Novel Strategies for Glioblastoma Treatment

Glioblastoma multiforme (GBM) is a grade IV glioma considered the most fatal cancer of the central nervous system (CNS), with less than a 5% survival rate after five years. The tumor heterogeneity, the high infiltrative behavior of its cells, and the blood-brain barrier (BBB) that limits the access of therapeutic drugs to the brain are the main reasons hampering the current standard treatment efficiency. Following the tumor resection, the infiltrative remaining GBM cells, which are resistant to chemotherapy and radiotherapy, can further invade the surrounding brain parenchyma. Consequently, the development of new strategies to treat parenchyma-infiltrating GBM cells, such as vaccines, nanotherapies, and tumor cells traps including drug delivery systems, is required. For example, the chemoattractant CXCL12, by binding to its CXCR4 receptor, activates signaling pathways that play a critical role in tumor progression and invasion, making it an interesting therapeutic target to properly control the direction of GBM cell migration for treatment proposes. Moreover, the interstitial fluid flow (IFF) is also implicated in increasing the GBM cell migration through the activation of the CXCL12-CXCR4 signaling pathway. However, due to its complex and variable nature, the influence of the IFF on the efficiency of drug delivery systems is not well understood yet. Therefore, this review discusses novel drug delivery strategies to overcome the GBM treatment limitations, focusing on chemokines such as CXCL12 as an innovative approach to reverse the migration of infiltrated GBM. Furthermore, recent developments regarding in vitro 3D culture systems aiming to mimic the dynamic peritumoral environment for the optimization of new drug delivery technologies are highlighted.

Multifunctional silica-coated mixed polymeric micelles for integrin-targeted therapy of pediatric patient-derived glioblastoma

Glioblastoma multiforme (GBM) remains a major cause of mortality because treatments are precluded by to the limited transport and penetration of chemotherapeutics across the blood-brain barrier. Pitavastatin (PTV) is a hydrophobic Food and Drug Administration (FDA)-approved anticholesterolemic agent with reported anti-GBM activity. In the present study, we encapsulate PTV in silica-coated polymeric micelles (SiO₂ PMs) surface-modified with the cyclic peptide Arg-Gly-Asp-Phe-Val (cRGDfV) that actively targets the α_vβ₃ integrin overexpressed in the BBB endothelium and GBM. A central composite design is utilized to optimize the preparation process and improve the drug encapsulation ratio from 131 to 780 μg/mL. The silica shell provides full colloidal stability upon extreme dilution and enables a better control of the release kinetics in vitro with 28% of the cargo released after 12 h. Furthermore, SiO₂ PMs show excellent compatibility and are internalized by human BBB endothelial cells, astrocytes and pericytes, as shown by confocal laser scanning fluorescence microscopy and flow cytometry. Finally, the anticancer efficacy is assessed in a pediatric patient-derived glioma cell line expressing high levels of the integrin subunits αv, β3 and β5. This PTV-loaded nanocarrier triggers apoptosis by reducing the mRNA level of anti-apoptotic genes NF-kβ, IL-6, BIRC1 and BIRC5 by 89%, 33%, 81% and 63%, respectively, and the cell viability by >60%. Overall, our results suggest the potential of these hybrid nanocarriers for the targeted therapy of GBM and other tumors overexpressing integrin receptors.

Bioscaffold-based study of glioblastoma cell behavior and drug delivery for tumor therapy

Glioblastoma multiforme (GBM) is a severe form of brain cancer with an average five-year survival rate of 6.7%. Current treatment strategies include surgical resection of the tumor area and lining the lesion site with therapeutics, which offer only a moderate impact on increasing survival rates. Drug-testing models based on the monolayer cell culture method may partially explain the lack of advancement in effective GBM treatment, because this model is limited in its ability to show heterogeneous cell-cell and cell-environment interactions as tumor cells in the in vivo state. The development of bioscaffold-based culture models is an important improvement in GBM research, preclinical trials, and targeted drug testing, through better mimicking of the heterogeneity of tumor environmental conditions. A major hurdle towards better GBM outcomes is in delivering medication across the blood-brain barrier (BBB), which normally prevents the crossing of materials into the treatment site. The delivery of therapeutics using bioscaffolds is a potential means of overcoming the BBB and could potentially facilitate long-lasting drug release. A number of natural and synthetic materials have been studied for their biodegradability, toxicity, distribution, and pharmaceutical stability, which are needed to determine the overall effectiveness and safety of glioblastoma treatment. This review summarizes advancements in the research of bioscaffold-based GBM cell growth systems and the potential of using bioscaffolds as a carrier for drug delivery.

Molecular Targets and Nanoparticulate Systems Designed for the Improved Therapeutic Intervention in Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is the most aggressive and fatal CNS related tumors, which is responsible for about 4% of cancer-related deaths. Current GBM therapy includes surgery, radiation, and chemotherapy. The effective chemotherapy of GBM is compromised by two barriers, i. e., the blood-brain barrier (BBB) and the blood tumor barrier (BTB). Therefore, novel therapeutic approaches are needed. Nanoparticles are one of the highly efficient drug delivery systems for a variety of chemotherapeutics that have gained massive attention from the last three decades. Perfectly designed nanoparticles have the ability to cross BBB and BTB and precisely deliver the chemotherapeutics to GBM tissue/cells. Nanoparticles can encapsulate both hydrophilic and lipophilic drugs, genes, proteins, and peptides, increase the stability of drugs by protecting them from degradation, improve plasma half-life, reduce adverse effects and control the release of drugs/genes at the desired site. This review focussed on the different signaling pathways altered in GBM cells to understand the rationale behind selecting new therapeutic targets, challenges in the drug delivery to the GBM, various transport routes in brain delivery, and recent advances in targeted delivery of different drug and gene loaded various lipidic, polymeric and inorganic nanoparticles in the effective management of GBM.

PAMAM Dendrimer Nanomolecules Utilized as Drug Delivery Systems for Potential Treatment of Glioblastoma: A Systematic Review

Glioblastoma (GB) is a grade IV astrocytoma that maintains a poor prognosis with respect to current treatment options. Despite major advancements in the fields of surgery and chemoradiotherapy over the last few decades, the life expectancy for someone with glioblastoma remains virtually unchanged and warrants a new approach for treatment. Poly(amidoamine) (PAMAM) dendrimers are a type of nanomolecule that ranges in size (between 1 and 100 nm) and shape and can offer a new viable solution for the treatment of intracranial tumors, including glioblastoma. Their ability to deliver a variety of therapeutic cargo and penetrate the blood-brain barrier (BBB), while preserving low cytotoxicity, make them a favorable candidate for further investigation into the treatment of glioblastoma. Here, we present a systematic review of the current advancements in PAMAM dendrimer technology, including the wide spectrum of dendrimer generations formulated, surface modifications, core modifications, and conjugations developed thus far to enhance tumor specificity and tumor penetration for treatment of glioblastoma. Furthermore, we highlight the extensive variety of therapeutics capable of delivery by PAMAM dendrimers for the treatment of glioblastoma, including cytokines, peptides, drugs, siRNAs, miRNAs, and organic polyphenols. While there have been prolific results stemming from aggressive research into the field of dendrimer technology, there remains a nearly inexhaustible amount of questions that remain unanswered. Nevertheless, this technology is rapidly developing and is nearing the cusp of use for aggressive tumor treatment. To that end, we further highlight future prospects in focus as researchers continue developing more optimal vehicles for the delivery of therapeutic cargo.

The Extracellular Matrix and Biocompatible Materials in Glioblastoma Treatment

During cancer genesis, the extracellular matrix (ECM) in the human brain undergoes important transformations, starting to resemble embryonic brain cell milieu with a much denser structure. However, the stiffness of the tumor ECM does not preclude cancer cells from migration. The importance of the ECM role in normal brain tissue as well as in tumor homeostasis has engaged much effort in trials to implement ECM as a target and an instrument in the treatment of brain cancers. This review provides a detailed analysis of both experimental and applied approaches in combined therapy for gliomas in adults. In general, matrix materials for glioma treatment should have properties facilitating the simplest delivery into the body. Hence, to deliver an artificial implant directly into the operation cavity it should be packed into a gel form, while for bloodstream injections matrix needs to be in the form of polymer micelles, nanoparticles, etc. Furthermore, the delivered material should mimic biomechanical properties of the native tissue, support vital functions, and slow down or stop the proliferation of surrounding cells for a prolonged period. The authors propose a two-step approach aimed, on the one hand, at elimination of remaining cancer cells and on the other hand, at restoring normal brain tissue. Thereby, the first bioartificial matrix to be applied should have relatively low elastic modulus should be loaded with anticancer drugs, while the second material with a higher elastic modulus for neurite outgrowth support should contain specific factors stimulating neuroregeneration.

Cationic micelle: A promising nanocarrier for gene delivery with high transfection efficiency

Micelles have demonstrated an excellent ability to deliver several different types of therapeutic agents, including chemotherapy drugs, proteins, small-interfering RNA and DNA, into tumor cells. Cationic micelles, comprising self-assemblies of amphiphilic cationic polymers, have exhibited tremendous promise with respect to the delivery of therapy genes and gene transfection. To date, research in the field has focused on achieving an enhanced stability of the micellar assembly, prolonged circulation times and controlled release of the gene. This review focuses on the micelles as a nanosized carrier system for gene delivery, the system-related modifications for cytoplasm release, stability and biocompatibility, and clinic trials. In accordance with the development of synthetic chemistry and self-assembly technology, the structures and functionalities of micelles can be precisely controlled, and hence the synthetic micelles not only efficiently condense DNA, but also facilitate DNA endocytosis, endosomal escape, DNA uptake and nuclear transport, resulting in a comparable gene transfection of virus.

A Distinct Advantage to Intraarterial Delivery of 89Zr-Bevacizumab in PET Imaging of Mice With and Without Osmotic Opening of the Blood-Brain Barrier

Glioblastoma multiforme (GBM) is the most aggressive and common type of brain cancer. Five-year survival rates are below 12%, even with the most aggressive trimodal therapies. Poor blood-brain barrier (BBB) permeability of therapeutics is a major obstacle to efficacy. Intravenous administration of bevacizumab is the standard treatment for GBM. It has been recently demonstrated that a single intraarterial infusion of bevacizumab provides superior therapeutic outcomes in patients with recurrent GBM. Further GBM treatment benefits can be achieved through opening of the BBB before intraarterial infusion of bevacizumab. However, a rationale for intraarterial delivery and BBB opening when delivering antibodies is lacking. A method facilitating quantification of intraarterial delivery of bevacizumab is needed for more effective and personalized GBM treatment. Here, we demonstrate such a method using PET imaging of radiolabeled bevacizumab. Methods: Bevacizumab was conjugated with deferoxamine and subsequently radiolabeled with ⁸⁹Zr. ⁸⁹Zr-bevacizumab deferoxamine (⁸⁹Zr-BVDFO) was prepared with a specific radioactivity of 81.4 ± 7.4 MBq/mg (2.2 ± 0.2 μCi/mg). Brain uptake of ⁸⁹Zr-BVDFO on carotid artery and tail vein infusion with an intact BBB or with BBB opening with mannitol was initially monitored by dynamic PET, followed by whole-body PET/CT at 1 and 24 h after infusion. Th ex vivo biodistribution of ⁸⁹Zr-BVDFO was also determined. Results: Intraarterial administration of ⁸⁹Zr-BVDFO resulted in gradual accumulation of radioactivity in the ipsilateral hemisphere, with 9.16 ± 2.13 percentage injected dose/cm³ at the end of infusion. There was negligible signal observed in the contralateral hemisphere. BBB opening with mannitol before intraarterial infusion of ⁸⁹Zr-BVDFO resulted in faster and higher uptake in the ipsilateral hemisphere (23.58 ± 4.46 percentage injected dose/cm³) and negligible uptake in the contralateral hemisphere. In contrast, intravenous infusion of ⁸⁹Zr-BVDFO and subsequent BBB opening did not lead to uptake of radiotracer in the brain. The ex vivo biodistribution results validated the PET/CT studies. Conclusion: Our findings demonstrate that intraarterial delivery of bevacizumab into the brain across an osmotically opened BBB is effective, in contrast to the intravenous route.

Advances in the design of solid lipid nanoparticles and nanostructured lipid carriers for targeting brain diseases

Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) comprise a category of versatile drug delivery systems that have been used in the biomedical field for >25years. SLNs and NLCs have been used for the treatment of various diseases including cardiovascular and cerebrovascular, and are considered a standard treatment for the latter, due to their inherent ability to cross the blood brain barrier (BBB). In this review, a presentation of the most important brain diseases (brain cancer, ischemic stroke, Alzheimer's disease, Parkinson's disease and multiple sclerosis) is approached, followed by the basic fabrication techniques of SLNs and NLCs. A detailed description of the reported studies of the last seven years, of active and passive targeting SLNs and NLCs for the treatment of glioblastoma multiforme and of other brain cancers, as well as for the treatment of neurodegenerative diseases is also carried out. Finally, a brief description of the advantages, the disadvantages, and the future perspectives in the use of these nanocarriers is reported, aiming at giving an insight of the limitations that have to be overcome in order to result in a delivery system with high therapeutic efficacy and without the limitations of the existing nano-systems.

Self-assembled amphiphilic core-shell nanocarriers in line with the modern strategies for brain delivery

Disorders of the central nervous system (CNS) represent increasing social and economic problems all over the world which makes the effective transport of drugs to the brain a crucial need. In the last decade, many strategies were introduced to deliver drugs to the brain trying to overcome the challenge of the blood brain barrier (BBB) using both invasive and non-invasive methods. Non-invasive strategy represented in the application of nanocarriers became very common. One of the most hopeful nanoscopic carriers for brain delivery is core-shell nanocarriers or polymeric micelles (PMs). They are more advantageous than other nanocarriers. They offer small size, ease of preparation, ease of sterilization and the possibility of surface modification with various ligands. Hence, the aim of this review is to discuss modern strategies for brain delivery, micelles as a successful delivery system for the brain and how micelles could be modified to act as "magic bullets" for brain delivery.

Getting into the brain: liposome-based strategies for effective drug delivery across the blood-brain barrier

This review summarizes articles that have been reported in literature on liposome-based strategies for effective drug delivery across the blood–brain barrier. Due to their unique physicochemical characteristics, liposomes have been widely investigated for their application in drug delivery and in vivo bioimaging for the treatment and/or diagnosis of neurological diseases, such as Alzheimer’s, Parkinson’s, stroke, and glioma. Several strategies have been used to deliver drug and/or imaging agents to the brain. Covalent ligation of such macromolecules as peptides, antibodies, and RNA aptamers is an effective method for receptor-targeting liposomes, which allows their blood–brain barrier penetration and/or the delivery of their therapeutic molecule specifically to the disease site. Additionally, methods have been employed for the development of liposomes that can respond to external stimuli. It can be concluded that the development of liposomes for brain delivery is still in its infancy, although these systems have the potential to revolutionize the ways in which medicine is administered.

Reducible Micelleplexes are Stable Systems for Anti-miRNA Delivery in Cerebrospinal Fluid

Glioblastoma multiforme (GBM) and other central nervous system (CNS) cancers have poor long-term prognosis, and there is a significant need for improved treatments. GBM initiation and progression are mediated, in part, by microRNA (miRNA), which are endogenous posttranscriptional gene regulators. Misregulation of miRNAs is a potential target for therapeutic intervention in GBM. In this work, a micelle-like nanoparticle delivery system based upon the block copolymer poly(ethylene glycol-b-lactide-b-arginine) was designed with and without a reducible linkage between the lactide and RNA-binding peptide, R15, to assess the ability of the micelle-like particles to disassemble. Using confocal live cell imaging, intracellular dissociation was pronounced for the reducible micelleplexes. This dissociation was also supported by higher efficiency in a dual luciferase assay specific for the miRNA of interest, miR-21. Notably, micelleplexes were found to have significantly better stability and higher anti-miRNA activity in cerebrospinal fluid than in human plasma, suggesting an advantage for applying micelleplexes to CNS diseases and in vivo CNS therapeutics. The reducible delivery system was determined to be a promising delivery platform for the treatment of CNS diseases with miRNA therapy.

Delivery of a drug cache to glioma cells overexpressing platelet-derived growth factor receptor using lipid nanocarriers

AIM

Glioblastoma multiforme is a devastating disease with no curative options due to the difficulty in achieving sufficient quantities of effective chemotherapies into the tumor past the blood-brain barrier. Micelles loaded with temozolomide (TMZ) were designed to increase the delivery of this drug into the brain.

MATERIALS & METHODS

pH-responsive micelles composed of distearoyl phosphoethanolamine-PEG-2000-amine and N-palmitoyl homocysteine were surface-functionalized with PDGF peptide and Dylight 680 fluorophore.

RESULTS & CONCLUSION

PDGF-micelles containing TMZ have specific uptake and increased killing in glial cells compared with untargeted micelles. In vivo studies demonstrated selective accumulation of PDGF-micelles containing TMZ in orthotopic gliomas implanted in mice. Targeted micelle-based drug carrier systems hold potential for delivery of a wide variety of hydrophobic drugs thereby reducing its systemic toxicity.

Drug delivery approaches for the treatment of glioblastoma multiforme

CONTEXT

Glioblastoma multiforme (GBM) is by far the most common and aggressive form of glial tumor. It is characterized by a highly proliferative population of cells that invade surrounding tissue and that frequently recur after surgical resection and chemotherapy. Over the last decades, a number of promising novel pharmacological approaches have been investigated, but most of them have failed clinical trials due to some side-effects such as toxicity and poor drug delivery to the brain. The major obstacle in the treatment of GBM is the presence of the blood-brain barrier (BBB). Due to their relatively high molecular weight, most therapeutic drugs fail to cross the BBB from the blood circulation.

OBJECTIVE

This paper sheds light on the characteristics of GBM and the challenges of current pharmacological treatments. A closer look is given to the role of nanotechnology in the field of drug delivery, and its application in the treatment of brain tumors such as GBM.

METHOD

For this purpose, effort was made to select the most recent studies using predefined search criteria that included at least one of the following keywords in the PubMed and Medline databases: glioblastoma, drug delivery, blood-brain barrier, nanotechnology, and nanoparticle.

CONCLUSION

Breakthrough in nanotechnology offers promising applications in cancer therapy and targeted drug delivery. However, more efforts need to be devoted to the development of novel therapeutic strategies that enable the delivery of drugs to desired areas of the brain with limited side-effects and higher therapeutic efficiency.

Drug and cell encapsulation: alternative delivery options for the treatment of malignant brain tumors

Malignant brain tumors including glioblastoma are incurable cancers. Over the last years a number of promising novel treatment approaches have been investigated including the application of inhibitors of receptor tyrosine kinases and downstream targets, immune-based therapies and anti-angiogenic agents. Unfortunately so far the major clinical trials in glioblastoma patients did not deliver clear clinical benefits. Systemic brain tumor therapy is seriously hampered by poor drug delivery to the brain. Although in glioblastoma, the blood brain barrier is disrupted in the tumor core, the major part of the tumor is largely protected by an intact blood brain barrier. Active cytotoxic compounds encapsulated into liposomes, micelles, and nanoparticles constitute novel treatment options because they can be designed to facilitate entry into the brain parenchyma. In the case of biological therapeutics, encapsulation of therapeutic cells and their implantation into the surgical cavity represents another promising approach. This technology provides long term release of the active compound at the tumor site and reduces side effects associated with systemic delivery. The proof of principle of encapsulated cell factories has been successfully demonstrated in experimental animal models and should pave the way for clinical application. Here we review the challenges associated with the treatment of brain tumors and the different encapsulation options available for drugs and living cells, with an emphasis on alginate based cell encapsulation technology.