Advances in designing of polymeric micelles for biomedical application in brain related diseases

Polymer-based nanocarriers to transport therapeutic biomacromolecules across the blood-brain barrier

Therapeutic biomacromolecules such as genetic material, antibodies, growth factors and enzymes represent a novel therapeutic alternative for neurological diseases and disorders. In comparison to traditional therapeutics, which are mainly based on small molecular weight drugs that address the symptoms of these disorders, therapeutic biomacromolecules can reduce undesired side effects and target specific pathological pathways, thus paving the way towards personalized medicine. However, these biomacromolecules undergo degradation/denaturation processes in the physiological environment and show poor capacity to cross the blood-brain barrier (BBB). Consequently, they rarely reach the central nervous system (CNS) in their active form. Herein, we critically overview several polymeric nanocarriers that can protect and deliver therapeutic biomacromolecules across the BBB. Polymeric nanocarriers are first categorized based on their architecture (biodegradable solid nanoparticles, nanogels, dendrimers, self-assembled nanoparticles) that ultimately determines their physico-chemical properties and function. The available polymeric formulations are then thoroughly analyzed, placing particular attention on those strategies that ensure the stability of the biomacromolecules during their encapsulation process and promote their passage across the BBB by controlling their physical (e.g., mechanical properties, size, surface charge) and chemical (e.g., surface functional groups, targeting motifs) properties. Accordingly, this review gives a unique perspective on polymeric nanocarriers for the delivery of therapeutic biomacromolecules across the BBB, representing a concise, complete and easy-to-follow guide, which will be of high interest for chemists, material scientists, pharmacologists, and biologists. Besides, it also provides a critical perspective about the limited clinical translation of these systems. STATEMENT OF SIGNIFICANCE: The increasing incidence of central nervous system disorders is a major health concern. The use of therapeutic biomacromolecules has been placed in the spotlight of many investigations. However, reaching therapeutic concentration levels of biomacromolecules in the central nervous system is restricted by the blood-brain barrier and, thus, this represents the main clinical challenge when developing efficient therapies. Herein, we provide a critical discussion about the use of polymeric nanocarriers to deliver therapeutic biomacromolecules into the central nervous system, highlighting potential future directions to overcome the current challenges.

Unraveling the mechanisms of glioblastoma's resistance: investigating the influence of tumor suppressor p53 and non-coding RNAs

Glioblastoma (GB) is one of the most fatal CNS malignancies, and its high resistance to therapy and poor outcomes have made it one of the primary challenges in oncology. Resistance to standard therapy, i.e., radio-chemotherapy with temozolomide, is one of the principal causes of the poor prognostic outcomes of GB. Finding the molecular basis of GB resistance to therapy is key to creating effective solution approaches. The general problem of GB resistance is supervised by cancer suppressive protein, p53, and has become a very special interest in molecular research in recent decades. The principal aim of this manuscript is to perform a comprehensive survey on the complex network of interactions developed by p53 with non-coding RNAs (ncRNA) in the context of GB resistance. The present article details the functional aspects of p53 as a cellular stress response protein, including its roles in apoptosis, cell cycle regulation, and DNA repair in glioblastoma (GB), along with the disruption of p53 and its involvement in chemoresistance (CR). It also highlights several classes of ncRNAs, namely microRNAs, long ncRNAs, and circular RNAs, that manipulate p53 signaling in GB-CR. The article likewise explains how disruption in the expression of these ncRNAs can promote GB-CR and how it interacts with essential cellular functions, such as proliferation, apoptosis, and DNA repair. The manuscript also describes the potential of targeting p53 and ncRNAs with their diagnostic and prognostic potential as novel promising therapeutics for GB. Nevertheless, ncRNA-based biomarkers still present challenges for their suitability in GB resistance. However, modern research continues to discover novel prediction targets, potentially enhancing patient outcomes and therapeutic options. Therefore, the neutralization of this intricate regulatory network of GB resistance might have a primary clinical effect in fighting GB resistance therapy and thus might lead to a substantial increase in patient survival and quality of life.

Advancement in the Nose-to-Brain Drug delivery of FDA-approved drugs for the better management of Depression and Psychiatric disorders

The Prevalence of Depressive and Psychiatric disorders is increasing globally, and despite the availability of numerous FDA-approved drugs, treatment remains challenging. Many conventional antidepressants and antipsychotic formulations face issues such as low solubility, high first-pass metabolism, poor bioavailability, inadequate blood-brain barrier penetration, and systemic side effects. These challenges lead to reduced efficacy, slower onset of action, and decreased patient adherence to treatment. To address these problems, recent studies have explored the nose-to-brain route for drug delivery. This method offers several advantages, including non-invasive drug administration, direct access to the brain, rapid onset of action, reduced systemic exposure and side effects, avoidance of first-pass metabolism, enhanced bioavailability, precision dosing, and improved patient compliance. The formulations used for this approach include lipidic nanoparticles, polymeric nanoparticles, nasal gels, cubosomes, niosomes, polymeric micelles, nanosuspensions, nanoemulsions, nanocapsules, and elastosomes. This review analyzes and summarizes the published work on the nose-to-brain delivery of FDA-approved antidepressants and antipsychotic drugs, with a focus on the preparation, characterization, pharmacokinetics, pharmacodynamics, and toxicity profiling of these nanoformulations.

Preparation and characterization of poly(ethylene glycol)-b-poly(tert-butyl methacrylate) micelles as potential nanocarriers for donepezil

Polymeric micelles were prepared for the delivery of donepezil, a leading Alzheimer's disease drug, to enhance its transport across the blood-brain barrier (BBB). Poly(ethylene glycol)-b-poly(tert-butyl methacrylate) amphiphilic block copolymers were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. The polymers were characterized by gel permeation chromatography and nuclear magnetic resonance spectroscopy. Empty and donepezil loaded polymer micelles were formed using the dialysis method and characterized by dynamic light scattering and transmission electron microscopy. Drug loading efficiency and release behavior were monitored using UV/Vis spectroscopy, and cytotoxicity was evaluated via colorimetric tests and impedance measurements. Additionally, the permeability of the nanocarriers across an in vitro BBB culture model was assessed. Drug-loaded micelles demonstrated similar permeability to free donepezil but offered sustained release and improved stability. This micellar delivery system holds significant potential for improving therapeutic outcomes in Alzheimer's treatment by enhancing donepezil's delivery across the BBB. Improved BBB permeability and sustained drug release could lead to more effective concentration of the drug in the brain, potentially reducing peripheral cholinergic side effects, such as nausea and vomiting, often observed with traditional donepezil administration. This could result in better patient compliance and improved cognitive outcomes, making this nanocarrier system a promising alternative for Alzheimer's therapy.

Controlled Drug Release Systems for Cerebrovascular Diseases

This review offers a comprehensive exploration of optimized drug delivery systems tailored for controlled release and their crucial role in addressing cerebrovascular diseases. Through an in‐depth analysis, various controlled release methods, including nanoparticles, liposomes, hydrogels, and other emerging technologies are examined. Highlighting the importance of precise drug targeting, it is delved into the underlying mechanisms of these delivery systems and their potential to improve therapeutic outcomes while minimizing adverse effects. Additionally, the specific applications of these optimized drug delivery systems in treating cerebrovascular disorders such as ischemic stroke, cerebral aneurysms, and intracranial hemorrhage are discussed. By shedding light on the advancements in drug delivery techniques and their implications in cerebrovascular medicine, this review offers valuable insights into the future of therapeutic interventions in neurology.

Breaking Barriers in Alzheimer's Disease: the Role of Advanced Drug Delivery Systems

Alzheimer's disease (AD), characterized by cognitive impairment, brain plaques, and tangles, is a global health concern affecting millions. It involves the build-up of amyloid-β (Aβ) and tau proteins, the formation of neuritic plaques and neurofibrillary tangles, cholinergic system dysfunction, genetic variations, and mitochondrial dysfunction. Various signaling pathways and metabolic processes are implicated in AD, along with numerous biomarkers used for diagnosis, risk assessment, and research. Despite these, there is no cure or effective treatment for AD. It is critically important to address this immediately to develop novel drug delivery systems (NDDS) capable of targeting the brain and delivering therapeutic agents to modulate the pathological processes of AD. This review summarizes AD, its pathogenesis, related signaling pathways, biomarkers, conventional treatments, the need for NDDS, and their application in AD treatment. It also covers preclinical, clinical, and ongoing trials, patents, and marketed AD formulations.

Nanomedicine in Neuroprotection, Neuroregeneration, and Blood-Brain Barrier Modulation: A Narrative Review

Nanomedicine is a newer, promising approach to promote neuroprotection, neuroregeneration, and modulation of the blood-brain barrier. This review includes the integration of various nanomaterials in neurological disorders. In addition, gelatin-based hydrogels, which have huge potential due to biocompatibility, maintenance of porosity, and enhanced neural process outgrowth, are reviewed. Chemical modification of these hydrogels, especially with guanidine moieties, has shown improved neuron viability and underscores tailored biomaterial design in neural applications. This review further discusses strategies to modulate the blood-brain barrier-a factor critically associated with the effective delivery of drugs to the central nervous system. These advances bring supportive solutions to the solving of neurological conditions and innovative therapies for their treatment. Nanomedicine, as applied to neuroscience, presents a significant leap forward in new therapeutic strategies that might help raise the treatment and management of neurological disorders to much better levels. Our aim was to summarize the current state-of-knowledge in this field.

Current Overview on the Use of Nanosized Drug Delivery Systems in the Treatment of Neurodegenerative Diseases

Neurodegenerative diseases, encompassing conditions such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, amyotrophic lateral sclerosis, prion disease, and Huntington's disease, present a growing health concern as human life expectancy increases. Despite this, effective treatments to halt disease progression remain elusive due to various factors, including challenges in drug delivery across physiological barriers like the blood-brain barrier and patient compliance issues leading to treatment discontinuation. In response, innovative treatment approaches leveraging noninvasive techniques with higher patient compliance are emerging as promising alternatives. This Review aims to synthesize current treatment options and the challenges encountered in managing neurodegenerative diseases, while also exploring innovative treatment modalities. Specifically, noninvasive strategies such as intranasal administration and nanosized drug delivery systems are gaining prominence for their potential to enhance treatment efficacy and patient adherence. Nanosized drug delivery systems, including liposomes, polymeric micelles, and nanoparticles, are evaluated within the context of outstanding studies. The advantages and disadvantages of these approaches are discussed, providing insights into their therapeutic potential and limitations. Through this comprehensive examination, this Review contributes to the ongoing discourse surrounding the development of effective treatments for neurodegenerative diseases.

How Precise are Nanomedicines in Overcoming the Blood-Brain Barrier? A Comprehensive Review of the Literature

New nanotechnology strategies for enhancing drug delivery in brain disorders have recently received increasing attention from drug designers. The treatment of neurological conditions, including brain tumors, stroke, Parkinson's Disease (PD), and Alzheimer's disease (AD), may be greatly influenced by nanotechnology. Numerous studies on neurodegeneration have demonstrated the effective application of nanomaterials in the treatment of brain illnesses. Nanocarriers (NCs) have made it easier to deliver drugs precisely to where they are needed. Thus, the most effective use of nanomaterials is in the treatment of various brain diseases, as this amplifies the overall impact of medication and emphasizes the significance of nanotherapeutics through gene therapy, enzyme replacement therapy, and blood-barrier mechanisms. Recent advances in nanotechnology have led to the development of multifunctional nanotherapeutic agents, a promising treatment for brain disorders. This novel method reduces the side effects and improves treatment outcomes. This review critically assesses efficient nano-based systems in light of obstacles and outstanding achievements. Nanocarriers that transfer medications across the blood-brain barrier and nano-assisted therapies, including nano-immunotherapy, nano-gene therapy, nano enzyme replacement therapy, scaffolds, and 3D to 6D printing, have been widely explored for the treatment of brain disorders. This study aimed to evaluate existing literature regarding the use of nanotechnology in the development of drug delivery systems that can penetrate the blood-brain barrier (BBB) and deliver therapeutic agents to treat various brain disorders.

Borneol-Modified Schisandrin B Micelles Cross the Blood-Brain Barrier To Treat Alzheimer's Disease in Aged Mice

Objective: Schisandrin B (Sch B) is a bioactive dibenzocyclooctadiene derizative that is prevalent in the fruit of Schisandra chinensis. Numerous studies have demonstrated that Sch B has a neuroprotective action by reducing oxidative stress and effectively preventing inflammation. It follows that Sch B is a potential treatment for Alzheimer's disease (AD). However, the drug's solubility, bioavailability, and lower permeability of the blood-brain barrier (BBB) can all reduce its efficacy during the therapy process. Therefore, this study constructed borneol-modified schisandrin B micelles (Bor-Sch B-Ms), which increase brain targeting by accurately delivering medications to the brain, effectively improving bioavailability. High therapeutic efficacy has been achieved at the pathological site. Methods: Bor-Sch B-Ms were prepared using the thin film dispersion approach in this article. On the one hand, to observe the targeting effect of borneol, we constructed a blood-brain barrier (BBB) model in vitro and studied the ability of micelles to cross the BBB. On the other hand, the distribution of micelle drugs and their related pharmacological effects on neuroinflammation, oxidative stress, and neuronal damage were studied through in vivo administration in mice. Results: In vitro studies have demonstrated that the drug uptake of bEnd.3 cells was increased by the borneol alteration on the surface of the nano micelles, implying that Bor-Sch B-Ms can promote the therapeutic effect of N2a cells. This could result in more medicines entering the BBB. In addition, in vivo studies revealed that the distribution and circulation time of medications in the brain tissue were significantly higher than those in other groups, making it more suitable for the treatment of central nervous system diseases. Conclusion: As a novel nanodrug delivery system, borneol modified schisandrin B micelles have promising research prospects in the treatment of Alzheimer's disease.

NIR-Emitting Gold Nanoclusters Encapsulated in PS-b-PEG Polymer Micelles

Gold nanoclusters (AuNCs) are an emerging type of luminescent probe, featuring good biocompatibility, high photostability, and large Stoke shifts. Their lack of colloidal stability is, however, a drawback for many applications. Here, we report the stabilization of AuNCs emitting in the NIR by a thiol-terminated polystyrene chain (Mn = 5000 g mol-1). The optical properties of this nanocomposite remain invariant for 2 years in THF. To use the PS5k-AuNCs in an aqueous environment, these were encapsulated into polymer micelles using a polystyrene-b-poly(ethylene glycol) copolymer. The resulting hierarchical constructs, with diameters of ca. 125 to 215 nm, have promising properties for applications as luminescent probes such as contrast agents for biomedical imaging.

Non-coding RNAs (ncRNAs) and multidrug resistance in glioblastoma: Therapeutic challenges and opportunities

Non-coding RNAs (ncRNAs) have been recognized as pivotal regulators of transcriptional and post-transcriptional gene modulation, exerting a profound influence on a diverse array of biological and pathological cascades, including the intricate mechanisms underlying tumorigenesis and the acquisition of drug resistance in neoplastic cells. Glioblastoma (GBM), recognized as the foremost and most aggressive neoplasm originating in the brain, is distinguished by its formidable resistance to the cytotoxic effects of chemotherapeutic agents and ionizing radiation. Recent years have witnessed an escalating interest in comprehending the involvement of ncRNAs, particularly lncRNAs, in GBM chemoresistance. LncRNAs, a subclass of ncRNAs, have been demonstrated as dynamic modulators of gene expression at the epigenetic, transcriptional, and post-transcriptional levels. Disruption in the regulation of lncRNAs has been observed across various human malignancies, including GBM, and has been linked with developing multidrug resistance (MDR) against standard chemotherapeutic agents. The potential of targeting specific ncRNAs or their downstream effectors to surmount chemoresistance is also critically evaluated, specifically focusing on ongoing preclinical and clinical investigations exploring ncRNA-based therapeutic strategies for glioblastoma. Nonetheless, targeting lncRNAs for therapeutic objectives presents hurdles, including overcoming the blood-brain barrier and the brief lifespan of oligonucleotide RNA molecules. Understanding the complex relationship between ncRNAs and the chemoresistance characteristic in glioblastoma provides valuable insights into the fundamental molecular mechanisms. It opens the path for the progression of innovative and effective therapeutic approaches to counter the therapeutic challenges posed by this aggressive brain tumor. This comprehensive review highlights the complex functions of diverse ncRNAs, including miRNAs, circRNAs, and lncRNAs, in mediating glioblastoma's chemoresistance.

Polymeric micelles loaded in situ gel with prednisolone acetate for ocular inflammation: development and evaluation

Aim: Our study developed a prednisolone acetate polymeric micelles (PM) system for ocular inflammation related to allergic uveitis. Methods: For PM development, a thin-film hydration procedure was used. Irritation, in vitro, ex vivo transcorneal permeation, micelle size, entrapment efficiency and histology within the eye were all calculated for PM. Results: The optimized in situ gel (A4) showed superior ex vivo transcorneal permeation with zero-order kinetics. Conclusion: The developed formulation could be a promising candidate for treating anterior uveitis via topical application to the anterior segment of the eye.

Polymeric micelles as potent islet amyloid inhibitors: current advances and future perspectives

Diabetes mellitus (DM) has become one of the most prevalent diseases across the globe, mainly because of the inability of existing treatment strategies to target its root cause (i.e., pancreatic β cell damage). Polymeric micelles (PMs) have gained attention as a treatment option for DM by targeting misfolded islet amyloid polypeptide protein (IAPP), which is common in more than 90% of patients with DM patients. Such misfolding could result from either oxidative stress or mutation in the gene encoding IAPP. In this review, we discuss progress in the design of PMs to halt islet amyloidosis along with their mechanism and dynamics of interactions with IAPP. We also discuss the clinical challenges associated with the translation of PMs as anti-islet amyloidogenic agents. Teaser: Polymeric micelles are able to target misfolding of islet amyloid polypeptide protein in the pancreas owing to their amphiphilic properties and could help protect against β cell damage, thereby offering effective management of diabetes mellitus.

Nanosystems for gene therapy targeting brain damage caused by viral infections

Several human pathogens can cause long-lasting neurological damage. Despite the increasing clinical knowledge about these conditions, most still lack efficient therapeutic interventions. Gene therapy (GT) approaches comprise strategies to modify or adjust the expression or function of a gene, thus providing therapy for human diseases. Since recombinant nucleic acids used in GT have physicochemical limitations and can fail to reach the desired tissue, viral and non-viral vectors are applied to mediate gene delivery. Although viral vectors are associated to high levels of transfection, non-viral vectors are safer and have been further explored. Different types of nanosystems consisting of lipids, polymeric and inorganic materials are applied as non-viral vectors. In this review, we discuss potential targets for GT intervention in order to prevent neurological damage associated to infectious diseases as well as the role of nanosized non-viral vectors as agents to help the selective delivery of these gene-modifying molecules. Application of non-viral vectors for delivery of GT effectors comprise a promising alternative to treat brain inflammation induced by viral infections.

Nano-inspired smart medicines targeting brain cancer: diagnosis and treatment

Cancer, despite being the bull's eye for the research community, accounts for a large number of morbidity and mortality. Cancer of the brain is considered the most intractable, with the least diagnosis rates, hence treatment and survival. Despite the extensive development of therapeutic molecules, their targeting to the diseased site is a challenge. Specially tailored nanoparticles can efficiently deliver drugs and genes to the brain to treat tumours and diseases. These nanotechnology-based strategies target the blood-brain barrier, the local space, or a specific cell type. These nanoparticles are preferred over other forms of targeted drug delivery due to the chances for controlled delivery of therapeutic cargo to the intended receptor. Targeted cancer therapy involves using specific receptor-blocking compounds that block the spreading or growth of cancerous cells. This review presents an account of the recent applications of nano-based cancer theragnostic, which deal in conjunct functionalities of nanoparticles for effective diagnosis and treatment of cancer. It commences with an introduction to tumours of the brain and their grades, followed by hurdles in its conventional diagnosis and treatment. The characteristic mechanism of nanoparticles for efficiently tracing brain tumour grade and delivery of therapeutic genes or drugs has been summarised. Nanocarriers like liposomes have been widely used and commercialized for human brain cancer treatment. However, nano-inspired structures await their translational recognition. The green synthesis of nanomaterials and their advantages have been discussed. The article highlights the challenges in the nano-modulation of brain cancer and its future outlook.

Role of nucleic acid-based polymeric micelles in treating lung diseases

The prevalence of lung diseases is increasing year by year and existing drug therapies only provide symptomatic relief rather than targeting the actual cause. Nucleic acids can be used as an alternative therapeutic approach owing to their potential to reform a homeostatic balance by upregulating protective genes or downregulating damaging genes. However, their inherent properties, such as poor stability, ineffective cellular uptake, negative charge and so on, hinder their clinical utility. Such limitations can be overcome by exploiting the functional chemistry of polymeric micelles (PMs) for site-specific delivery, transfection efficiency and improved stability. With this objective, the present work describes the advancements made in designing nucleic acid-based PMs for treating lung diseases followed by approaches requiring consideration for clinical applications.

Andrographis paniculata Dosage Forms and Advances in Nanoparticulate Delivery Systems: An Overview

Andrographis paniculata is a well-known Asian medicinal plant with a major phytoconstituent of diterpene lactones, such as andrographolide, 14-deoxyandrographolide, and neoandrographolide. A World Health Organization (WHO) monograph on selected medicinal plants showed that A. paniculata extracts and its major diterpene lactones have promising anti-inflammatory, antidiabetic, antimalarial, anticancer, antifungal, antibacterial, antioxidant, and hypoglycemic activities. However, these active phytochemicals have poor water solubility and bioavailability when delivered in a conventional dosage form. These biological barriers can be mitigated if the extract or isolated compound are delivered as nanoparticles. This review discusses existing studies and marketed products of A. paniculata in solid, liquid, semi-solid, and gaseous dosage forms, either as an extract or isolated pure compounds, as well as their deficits in reaching maximum bioavailability. The pharmaceutics and pharmacological activity of A. paniculata as a nano-delivery system are also discussed.