Nanotechnological advances for the delivery of CNS therapeutics

Charge-switchable cell-penetrating peptides for rerouting nanoparticles to glioblastoma treatment

Glioblastoma (GB) is one of the most lethal types of neoplasms with unique anatomic, physiologic, and pathologic features that usually persist after exposure to standard therapeutic modalities. It is biologically aggressive, and the existence of the blood-brain barrier (BBB) limits the efficacy of standard therapies. In this work, we hypothesize the potential of surface-functionalized ultra-small nanostructured lipid carriers (usNLCs) with charge-switchable cell-penetrating peptides (CPPs) to overcome this biological barrier and improve targeted delivery to brain tumor tissues. The big question is: what is the potential of CPPs in directing nanoparticles toward brain tumor tissue? To answer this question, the usNLCs were functionalized with distinct biomolecules [five CPPs, c(RGDfK) and transferrin, Tf] through electrostatic interaction and its ability as a targeting approach to BBB (HBMEC) and glioma cells (U87 cells) evaluated in terms of physicochemical properties, cellular uptake, permeability in a 2D-BBB model, and tumor growth inhibition. Monte Carlo simulations elucidated CPP adsorption patterns. The permeability studies revealed that targeted usNLCs, especially usNLCsTf and usNLCsCPP4, exhibited an increased permeability coefficient compared to the non-targeted usNLCs. Functionalized usNLCs evidenced enhanced uptake in BBB cells, with smaller CPPs showing higher internalization (CPP1 and CPP2). Similarly, functionalized usNLCs exhibited more significant cytotoxicity in glioma cells, with specific CPPs promoting favorable internalization. Analysis of the endocytic pathway indicated that usNLCsCPPs were mainly internalized by direct translocation and caveolae-mediated endocytosis. Optimal usNLCs with dual targeting capabilities to both BBB and GB cells provide a promising therapeutic strategy for GB.

Tailored Borneol-Modified Lipid Nanoparticles Nasal Spray for Enhanced Nose-to-Brain Delivery to Central Nervous System Diseases

The nanodrug delivery system-based nasal spray (NDDS-NS) can bypass the blood-brain barrier and deliver drugs directly to the brain, offering unparalleled advantages in the treatment of central nervous system (CNS) diseases. However, the current design of NNDS-NS is excessively focused on mucosal absorption while neglecting the impact of nasal deposition on nose-to-brain drug delivery, resulting in an unsatisfactory nose-to-brain delivery efficiency. In this study, the effect of the dispersion medium viscosity on nasal drug deposition and nose-to-brain delivery in NDDS-NS was elucidated. The optimized formulation F5 (39.36 mPa·s) demonstrated significantly higher olfactory deposition fraction (ODF) of 23.58%, and a strong correlation between ODF and intracerebral drug delivery (R2 = 0.7755) was observed. Building upon this understanding, a borneol-modified lipid nanoparticle nasal spray (BLNP-NS) that combined both nasal deposition and mucosal absorption was designed for efficient nose-to-brain delivery. BLNP-NS exhibited an accelerated onset of action and enhanced brain targeting efficiency, which could be attributed to borneol modification facilitating the opening of tight junction channels. Furthermore, BLNP-NS showed superiority in a chronic migraine rat model. It not only provided rapid relief of migraine symptoms but also reversed neuroinflammation-induced hyperalgesia. The results revealed that borneol modification could induce the polarization of microglia, regulate the neuroinflammatory microenvironment, and repair the neuronal damage caused by neuroinflammation. This study highlights the impact of dispersion medium viscosity on the nose-to-brain delivery process of NDDS-NS and serves as a bridge between the formulation development and clinical transformation of NDDS-NS for the treatment of CNS diseases.

Advances in Intrathecal Nanoparticle Delivery: Targeting the Blood-Cerebrospinal Fluid Barrier for Enhanced CNS Drug Delivery

The blood-cerebrospinal fluid barrier (BCSFB) tightly regulates molecular exchanges between the bloodstream and cerebrospinal fluid (CSF), creating challenges for effective central nervous system (CNS) drug delivery. This review assesses intrathecal (IT) nanoparticle (NP) delivery systems that aim to enhance drug delivery by circumventing the BCSFB, complementing approaches that target the blood-brain barrier (BBB). Active pharmaceutical ingredients (APIs) face hurdles like restricted CNS distribution and rapid clearance, which diminish the efficacy of IT therapies. NPs can be engineered to extend drug circulation times, improve CNS penetration, and facilitate sustained release. This review discusses key pharmacokinetic (PK) parameters essential for the effectiveness of these systems. NPs can quickly traverse the subarachnoid space and remain within the leptomeninges for extended periods, often exceeding three weeks. Some designs enable deeper brain parenchyma penetration. Approximately 80% of NPs in the CSF are cleared through the perivascular glymphatic pathway, with microglia-mediated transport significantly contributing to their paravascular clearance. This review synthesizes recent progress in IT-NP delivery across the BCSFB, highlighting critical findings, ongoing challenges, and the therapeutic potential of surface modifications and targeted delivery strategies.

Design, synthesis, biological evaluation, and molecular modeling simulations of new phthalazine-1,4-dione derivatives as anti-Alzheimer's agents

The development of targeted phthalazine-1,4-dione acetylcholinesterase (AChE) inhibitors for treating Alzheimer's disease involved the synthesis of 32 compounds via a multistage process. Various analytical techniques confirmed the compounds' identities. Thirteen compounds were found to inhibit AChE by more than 50% without affecting butyrylcholinesterase (BChE). Among these, three compounds, 8m, 8n, and 8p, exhibited extraordinary activity similar to donepezil, a reference AChE inhibitor. During enzyme kinetic studies, compound 8n, displaying the highest AChE inhibitory activity, underwent evaluation at three concentrations (2 × IC50, IC50, and IC50/2). Lineweaver-Burk plots indicated mixed inhibition activity for compound 8n against AChE, suggesting a combination of competitive and noncompetitive characteristics. Additionally, effective derivatives 8m, 8n, and 8p exhibited high blood-brain barrier (BBB) permeability in in vitro parallel artificial membrane permeability assay tests. Molecular docking studies revealed that these compounds bind to the enzyme's active site residues in a position similar to donepezil. Molecular dynamic simulations confirmed the stability of the protein-ligand system, and the chemical reactivity characteristics of the compounds were investigated using density functional theory. The compounds' wide energy gaps suggest stability and therapeutic potential. This research represents a significant step toward finding a potential cure for Alzheimer's disease. However, further research and testing are required to determine the compounds' safety and efficacy. The unique structure of phthalazine derivatives makes them suitable for various biological activities, and these compounds show promise for developing effective drugs for treating Alzheimer's disease. Overall, the development of these targeted compounds is a crucial advancement in the search for an effective treatment for Alzheimer's disease.

Liposomal Nanomaterials: A Rising Star in Glioma Treatment

Glioma is a primary malignant tumor in the central nervous system. In recent years, the treatment of glioma has developed rapidly, but the overall survival of glioma patients has not significantly improved. Due to the presence of the blood-brain barrier and intracranial tumor barrier, many drugs with good effects to cure glioma in vitro cannot be accurately transported to the corresponding lesions. In order to enable anti-tumor drugs to overcome the barriers and target glioma, nanodrug delivery systems have emerged recently. It is gratifying that liposomes, as a multifunctional nanodrug delivery carrier, which can be compatible with hydrophilic and hydrophobic drugs, easily functionalized by various targeted ligands, biodegradable, and hypoimmunogenic in vivo, has become a quality choice to solve the intractable problem of glioma medication. Therefore, we focused on the liposome nanodrug delivery system, and summarized its current research progress in glioma. Hopefully, this review may provide new ideas for the research and development of liposome-based nanomaterials for the clinical treatment of glioma.

Lipid nanoparticle mediated small interfering RNA delivery as a potential therapy for Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative condition that exhibits a gradual decline in cognitive function and is prevalent among a significant number of individuals globally. The use of small interfering RNA (siRNA) molecules in RNA interference (RNAi) presents a promising therapeutic strategy for AD. Lipid nanoparticles (LNPs) have been developed as a delivery vehicle for siRNA, which can selectively suppress target genes, by enhancing cellular uptake and safeguarding siRNA from degradation. Numerous research studies have exhibited the effectiveness of LNP-mediated siRNA delivery in reducing amyloid beta (Aβ) levels and enhancing cognitive function in animal models of AD. The feasibility of employing LNP-mediated siRNA delivery as a therapeutic approach for AD is emphasized by the encouraging outcomes reported in clinical studies for other medical conditions. The use of LNP-mediated siRNA delivery has emerged as a promising strategy to slow down or even reverse the progression of AD by targeting the synthesis of tau phosphorylation and other genes linked to the condition. Improvement of the delivery mechanism and determination of the most suitable siRNA targets are crucial for the efficacious management of AD. This review focuses on the delivery of siRNA through LNPs as a promising therapeutic strategy for AD, based on the available literature.

Advances in Engineered Nanoparticles for the Treatment of Ischemic Stroke by Enhancing Angiogenesis

Angiogenesis, or the formation of new blood vessels, is a natural defensive mechanism that aids in the restoration of oxygen and nutrition delivery to injured brain tissue after an ischemic stroke. Angiogenesis, by increasing vessel development, may maintain brain perfusion, enabling neuronal survival, brain plasticity, and neurologic recovery. Induction of angiogenesis and the formation of new vessels aid in neurorepair processes such as neurogenesis and synaptogenesis. Advanced nano drug delivery systems hold promise for treatment stroke by facilitating efficient transportation across the the blood-brain barrier and maintaining optimal drug concentrations. Nanoparticle has recently been shown to greatly boost angiogenesis and decrease vascular permeability, as well as improve neuroplasticity and neurological recovery after ischemic stroke. We describe current breakthroughs in the development of nanoparticle-based treatments for better angiogenesis therapy for ischemic stroke employing polymeric nanoparticles, liposomes, inorganic nanoparticles, and biomimetic nanoparticles in this study. We outline new nanoparticles in detail, review the hurdles and strategies for conveying nanoparticle to lesions, and demonstrate the most recent advances in nanoparticle in angiogenesis for stroke treatment.

Blood-brain barrier biomarkers

The blood-brain barrier (BBB) is a dynamic interface that regulates the exchange of molecules and cells between the brain parenchyma and the peripheral blood. The BBB is mainly composed of endothelial cells, astrocytes and pericytes. The integrity of this structure is essential for maintaining brain and spinal cord homeostasis and protection from injury or disease. However, in various neurological disorders, such as traumatic brain injury, Alzheimer's disease, and multiple sclerosis, the BBB can become compromised thus allowing passage of molecules and cells in and out of the central nervous system parenchyma. These agents, however, can serve as biomarkers of BBB permeability and neuronal damage, and provide valuable information for diagnosis, prognosis and treatment. Herein, we provide an overview of the BBB and changes due to aging, and summarize current knowledge on biomarkers of BBB disruption and neurodegeneration, including permeability, cellular, molecular and imaging biomarkers. We also discuss the challenges and opportunities for developing a biomarker toolkit that can reliably assess the BBB in physiologic and pathophysiologic states.

Receptor-Assisted Nanotherapeutics for Overcoming the Blood-Brain Barrier

Blood-brain barrier (BBB) is a distinguishing checkpoint that segregates peripheral organs from neural compartment. It protects the central nervous system from harmful ambush of antigens and pathogens. Owing to such explicit selectivity, the BBB hinders passage of various neuroprotective drug molecules that escalates into poor attainability of neuroprotective agents towards the brain. However, few molecules can surpass the BBB and gain access in the brain parenchyma by exploiting surface transporters and receptors. For successful development of brain-targeted therapy, understanding of BBB transporters and receptors is crucial. This review focuses on the transporter and receptor-based mechanistic pathway that can be manoeuvred for better comprehension of reciprocity of receptors and nanotechnological vehicle delivery. Nanotechnology has emerged as one of the expedient noninvasive approaches for brain targeting via manipulating the hurdle of the BBB. Various nanovehicles are being reported for brain-targeted delivery such as nanoparticles, nanocrystals, nanoemulsion, nanolipid carriers, liposomes and other nanovesicles. Nanotechnology-aided brain targeting can be a strategic approach to circumvent the BBB without altering the inherent nature of the BBB.

Application of Nanocomposites and Nanoparticles in Treating Neurodegenerative Disorders

Neurodegenerative diseases represent a formidable global health challenge, affecting millions and imposing substantial burdens on healthcare systems worldwide. Conditions, like Alzheimer's, Parkinson's, and Huntington's diseases, among others, share common characteristics, such as neuronal loss, misfolded protein aggregation, and nervous system dysfunction. One of the major obstacles in treating these diseases is the presence of the blood-brain barrier, limiting the delivery of therapeutic agents to the central nervous system. Nanotechnology offers promising solutions to overcome these challenges. In Alzheimer's disease, NPs loaded with various compounds have shown remarkable promise in preventing amyloid-beta (Aβ) aggregation and reducing neurotoxicity. Parkinson's disease benefits from improved dopamine delivery and neuroprotection. Huntington's disease poses its own set of challenges, but nanotechnology continues to offer innovative solutions. The promising developments in nanoparticle-based interventions for neurodegenerative diseases, like amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS), have offered new avenues for effective treatment. Nanotechnology represents a promising frontier in biomedical research, offering tailored solutions to the complex challenges posed by neurodegenerative diseases. While much progress has been made, ongoing research is essential to optimize nanomaterial designs, improve targeting, and ensure biocompatibility and safety. Nanomaterials possess unique properties that make them excellent candidates for targeted drug delivery and neuroprotection. They can effectively bypass the blood-brain barrier, opening doors to precise drug delivery strategies. This review explores the extensive research on nanoparticles (NPs) and nanocomposites in diagnosing and treating neurodegenerative disorders. These nanomaterials exhibit exceptional abilities to target neurodegenerative processes and halt disease progression.

Optimized lipopolymers with curcumin to enhance AZD5582 and GDC0152 activity and downregulate inhibitors of apoptosis proteins in glioblastoma multiforme

Inhibition to glioblastoma multiforme (GBM) propagation is a critical challenge in clinical practice because binding of inhibitors of apoptosis proteins (IAPs) to caspase prevents cancer cells from death. In this study, folic acid (FA), lactoferrin (Lf) and rabies virus glycoprotein (RVG) were grafted on lipopolymers (LPs) composed of poly(ε-caprolactone) and Compritol 888 ATO to encapsulate AZD5582 (AZD), GDC0152 (GDC) and curcumin (CURC). The standard deviations of initial particle diameter and particle diameter after storage for 30 days were involved in LP composition optimization. The functionalized LPs were used to permeate the blood-brain barrier (BBB) and constrain IAP quantity in GBM cells. Experimental results revealed that an increase in Span 20 (emulsifier) concentration enlarged the size of LPs, and enhanced the entrapment and releasing efficiency of AZD, DGC and CURC. 1H nuclear magnetic resonance spectra showed that the hydrogen bonds between the LPs and drugs supported the sustained release of AZD, DGC and CURC from the LPs. The LPs modified with the three targeting biomolecules facilitated the penetration of AZD, GDC and CURC across the BBB, and could recognize U87MG cells and human brain cancer stem cells. Immunofluorescence staining, flow cytometry and western blot demonstrated that CURC-incorporated LPs enhanced AZD and GDC activity in suppressing cellular IAP 1 (cIAP1) and X-linked IAP (XIAP) levels, and raising caspase-3 level in GBM. Surface FA, Lf and RVG also promoted the ability of the drug-loaded LPs to avoid carcinoma growth. The current FA-, Lf- and RVG-crosslinked LPs carrying AZD, DGC and CURC can be promising in hindering IAP expressions for GBM management.

Microparticles and nanoparticles-based approaches to improve oral treatment of Helicobacter pylori infection

Helicobacter pylori is a gram-negative, spiral-shaped, flagellated bacterium that colonizes the stomach of half the world's population. Helicobacter pylori infection causes pathologies of varying severity. Standard oral therapy fails in 15-20% since the barriers of the oral route decrease the bioavailability of antibiotics and the intrinsic factors of bacteria increase the rates of resistance. Nanoparticles and microparticles are promising strategies for drug delivery into the gastric mucosa and targeting H. pylori. The variety of building blocks creates systems with distinct colloidal, surface, and biological properties. These features improve drug-pathogen interactions, eliminate drug depletion and overuse, and enable the association of multiple actives combating H. pylori on several fronts. Nanoparticles and microparticles are successfully used to overcome the barriers of the oral route, physicochemical inconveniences, and lack of selectivity of current therapy. They have proven efficient in employing promising anti-H. pylori compounds whose limitation is oral route instability, such as some antibiotics and natural products. However, the current challenge is the applicability of these strategies in clinical practice. For this reason, strategies employing a rational design are necessary, including in the development of nano- and microsystems for the oral route.

Exosomes as cutting-edge therapeutics in various biomedical applications: An update on engineering, delivery, and preclinical studies

Exosomes are cell-derived nanovesicles, circulating in different body fluids, and acting as an intercellular mechanism. They can be purified from culture media of different cell types and carry an enriched content of various protein and nucleic acid molecules originating from their parental cells. It was indicated that the exosomal cargo can mediate immune responses via many signaling pathways. Over recent years, the therapeutic effects of various exosome types were broadly investigated in many preclinical studies. Herein, we present an update on recent preclinical studies on exosomes as therapeutic and/or delivery agents for various applications. The exosome origin, structural modifications, natural or loaded active ingredients, size, and research outcomes were summarized for various diseases. Overall, the present article provides an overview of the latest exosome research interests and developments to clear the way for the clinical study design and application.

Recent Advancements in Nanocarrier-assisted Brain Delivery of Phytochemicals Against Neurological Diseases

Despite ongoing advancements in research, the inability of therapeutics to cross the blood-brain barrier (BBB) makes the treatment of neurological disorders (NDs) a challenging task, offering only partial symptomatic relief. Various adverse effects associated with existing approaches are another significant barrier that prompts the usage of structurally diverse phytochemicals as preventive/therapeutic lead against NDs in preclinical and clinical settings. Despite numerous beneficial properties, phytochemicals suffer from poor pharmacokinetic profile which limits their pharmacological activity and necessitates the utility of nanotechnology for efficient drug delivery. Nanocarriers have been shown to be proficient carriers that can enhance drug delivery, bioavailability, biocompatibility, and stability of phytochemicals. We, thus, conducted a meticulous literature survey using several electronic databases to gather relevant studies in order to provide a comprehensive summary about the use of nanocarriers in delivering phytochemicals as a treatment approach for NDs. Additionally, the review highlights the mechanisms of drug transport of nanocarriers across the BBB and explores their potential future applications in this emerging field.

Nanogels as novel drug nanocarriers for CNS drug delivery

Nanogels are highly recognized as adaptable drug delivery systems that significantly contribute to improving various therapies and diagnostic examinations for different human diseases. These three-dimensional, hydrophilic cross-linked polymers have the ability to absorb large amounts of water or biological fluids. Due to the growing demand for enhancing current therapies, nanogels have emerged as the next-generation drug delivery system. They effectively address the limitations of conventional drug therapy, such as poor stability, large particle size, and low drug loading efficiency. Nanogels find extensive use in the controlled delivery of therapeutic agents, reducing adverse drug effects and enabling lower therapeutic doses while maintaining enhanced efficacy and patient compliance. They are considered an innovative drug delivery system that highlights the shortcomings of traditional methods. This article covers several topics, including the involvement of nanogels in the nanomedicine sector, their advantages and limitations, ideal properties like biocompatibility, biodegradability, drug loading capacity, particle size, permeability, non-immunological response, and colloidal stability. Additionally, it provides information on nanogel classification, synthesis, drug release mechanisms, and various biological applications. The article also discusses barriers associated with brain targeting and the progress of nanogels as nanocarriers for delivering therapeutic agents to the central nervous system.

Cell membrane-based biomimetic vehicles for effective central nervous system target delivery: Insights and challenges

Central nervous system (CNS) disorders, including brain tumor, ischemic stroke, Alzheimer's disease, and Parkinson's disease, threaten human health. And the existence of the blood-brain barrier (BBB) hinders the delivery of drugs and the design of drug targeting delivery vehicles. Over the past decades, great interest has been given to cell membrane-based biomimetic vehicles since the rise of targeting drug delivery systems and biomimetic nanotechnology. Cell membranes are regarded as natural multifunction biomaterials, and provide potential for targeting delivery design and modification. Cell membrane-based biomimetic vehicles appear timely with the participation of cell membranes and nanoparticles, and raises new lights for BBB recognition and transport, and effective therapy with its biological multifunction and high biocompatibility. This review summarizes existing challenges in CNS target delivery and recent advances of different kinds of cell membrane-based biomimetic vehicles for effective CNS target delivery, and deliberates the BBB targeting mechanism. It also discusses the challenges and possibility of clinical translation, and presents new insights for development.

Small extracellular vesicles: a novel drug delivery system for neurodegenerative disorders

Neurodegenerative diseases (NDs) have a slow onset and are usually detected late during disease. NDs are often difficult to cure due to the presence of the blood-brain barrier (BBB), which makes it difficult to find effective treatments and drugs, causing great stress and financial burden to families and society. Currently, small extracellular vesicles (sEVs) are the most promising drug delivery systems (DDSs) for targeted delivery of molecules to specific sites in the brain as a therapeutic vehicle due to their low toxicity, low immunogenicity, high stability, high delivery efficiency, high biocompatibility and trans-BBB functionality. Here, we review the therapeutic application of sEVs in several NDs, including Alzheimer's disease, Parkinson's disease, and Huntington's disease, discuss the current barriers associated with sEVs and brain-targeted DDS, and suggest future research directions.

Intranasal Lipid Nanoparticles Containing Bioactive Compounds Obtained from Marine Sources to Manage Neurodegenerative Diseases

Marine sources contain several bioactive compounds with high therapeutic potential, such as remarkable antioxidant activity that can reduce oxidative stress related to the pathogenesis of neurodegenerative diseases. Indeed, there has been a growing interest in these natural sources, especially those resulting from the processing of marine organisms (i.e., marine bio-waste), to obtain natural antioxidants as an alternative to synthetic antioxidants in a sustainable approach to promote circularity by recovering and creating value from these bio-wastes. However, despite their expected potential to prevent, delay, or treat neurodegenerative diseases, antioxidant compounds may have difficulty reaching the brain due to the need to cross the blood–brain barrier (BBB). In this regard, alternative delivery systems administered by different routes have been proposed, including intranasal administration of lipid nanoparticles, such as solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC), which have shown promising results. Intranasal administration shows several advantages, including the fact that molecules do not need to cross the BBB to reach the central nervous system (CNS), as they can be transported directly from the nasal cavity to the brain (i.e., nose-to-brain transport). The benefits of using SLN and NLC for intranasal delivery of natural bioactive compounds for the treatment of neurodegenerative diseases have shown relevant outcomes through in vitro and in vivo studies. Noteworthy, for bioactive compounds obtained from marine bio-waste, few studies have been reported, showing the open potential of this research area. This review updates the state of the art of using SLN and NLC to transport bioactive compounds from different sources, in particular, those obtained from marine bio-waste, and their potential application in the treatment of neurodegenerative diseases.

Harnessing nanobiotechnology for cerebral ischemic stroke management

Cerebral ischemic stroke remains one of the most serious neurological disorders that pose threats to human health, causing a large amount of long-term disability or even death throughout the world. Based on its physiologic and pathological features, there are limited available therapeutic options for effective ischemic stroke management. Encouragingly, a rapid advancement of nanobiotechnology is bringing new insights into exploring more alternative strategies against cerebral ischemic stroke, which can cleverly overcome the limitations related to conventional treatment methods. Therefore, this review focuses on the recent achievements of nanobiotechnology for ischemic stroke management, which emphasizes diverse targeted delivery strategies using various nanoplatforms including liposomes, micelles, polymeric nanoparticles, nanogels, inorganic nanomaterials, and cell-derived nano-vectors based on the pathophysiological features of ischemic stroke. Moreover, different therapeutic approaches against ischemic stroke such as neuroprotection, anti-inflammation, thrombolysis, increased blood-brain barrier penetration and reactive oxygen species scavenging are highlighted. Meanwhile, this review discusses how these versatile nanoplatforms were designed to assist in the treatment of ischemic stroke. Based on this, challenges, opportunities, and future perspectives using nanobiotechnology through rational design for effective ischemic stroke management are revealed.

Role of Nanomedicine-Based Therapeutics in the Treatment of CNS Disorders

Central nervous system disorders, especially neurodegenerative diseases, are a public health priority and demand a strong scientific response. Various therapy procedures have been used in the past, but their therapeutic value has been insufficient. The blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier is two of the barriers that protect the central nervous system (CNS), but are the main barriers to medicine delivery into the CNS for treating CNS disorders, such as brain tumors, Parkinson's disease, Alzheimer's disease, and Huntington's disease. Nanotechnology-based medicinal approaches deliver valuable cargos targeting molecular and cellular processes with greater safety, efficacy, and specificity than traditional approaches. CNS diseases include a wide range of brain ailments connected to short- and long-term disability. They affect millions of people worldwide and are anticipated to become more common in the coming years. Nanotechnology-based brain therapy could solve the BBB problem. This review analyzes nanomedicine's role in medication delivery; immunotherapy, chemotherapy, and gene therapy are combined with nanomedicines to treat CNS disorders. We also evaluated nanotechnology-based approaches for CNS disease amelioration, with the intention of stimulating the immune system by delivering medications across the BBB.

Progresses in Nano-Enabled Platforms for the Treatment of Vaginal Disorders

BACKGROUND

The most common vaginal disorders are within the uterus. According to the latest statistics, vaginal disorders occur in 50% to 60% of females. Although curative treatments rely on surgical therapy, still first-line treatment is a non invasive drug. Conventional therapies are available in the oral and parenteral route, leading to nonspecific targeting, which can cause dose-related side effects. Vaginal disorders are localized uterine disorders in which intrauterine delivery via the vaginal site is deemed the preferable route to mitigate clinical drug delivery limitations.

OBJECTIVE

This study emphasizes the progress of site-specific and controlled delivery of therapeutics in the treatment of vaginal disorders and systemic adverse effects as well as the therapeutic efficacy.

METHODS

Related research reports and patents associated with topics are collected, utilized, and summarized the key findings.

RESULTS

The comprehensive literature study and patents like (US 9393216 B2), (JP6672370B2), and (WO2018041268A1) indicated that nanocarriers are effective above traditional treatments and have some significant efficacy with novelty.

CONCLUSION

Nowadays, site-specific and controlled delivery of therapeutics for the treatment of vaginal disorders is essential to prevent systemic adverse effects and therapeutic efficacy would be more effective. Nanocarriers have therefore been used to bypass the problems associated with traditional delivery systems for the vaginal disorder.

Multifaceted role of polyphenols in the treatment and management of neurodegenerative diseases

Neurodegenerative diseases (NDDs) are conditions that cause neuron structure and/or function to deteriorate over time. Genetic alterations may be responsible for several NDDs. However, a multitude of physiological systems can trigger neurodegeneration. Several NDDs, such as Huntington's, Parkinson's, and Alzheimer's, are assigned to oxidative stress (OS). Low concentrations of reactive oxygen and nitrogen species are crucial for maintaining normal brain activities, as their increasing concentrations can promote neural apoptosis. OS-mediated neurodegeneration has been linked to several factors, including notable dysfunction of mitochondria, excitotoxicity, and Ca²⁺ stress. However, synthetic drugs are commonly utilized to treat most NDDs, and these treatments have been known to have side effects during treatment. According to providing empirical evidence, studies have discovered many occurring natural components in plants used to treat NDDs. Polyphenols are often safer and have lesser side effects. As, epigallocatechin-3-gallate, resveratrol, curcumin, quercetin, celastrol, berberine, genistein, and luteolin have p-values less than 0.05, so they are typically considered to be statistically significant. These polyphenols could be a choice of interest as therapeutics for NDDs. This review highlighted to discusses the putative effectiveness of polyphenols against the most prevalent NDDs.

Lipid nanoparticles strategies to modify pharmacokinetics of central nervous system targeting drugs: Crossing or circumventing the blood-brain barrier (BBB) to manage neurological disorders

The main limitation to the success of central nervous system (CNS) therapies lies in the difficulty for drugs to cross the blood-brain barrier (BBB) and reach the brain. Regarding its structure and enzymatic complexity, crossing the BBB is a challenge, although several alternatives have been identified. For instance, the use of drugs encapsulated in lipid nanoparticles has been described as one of the most efficient approaches to bypass the BBB, as they allow the passage of drugs through this barrier, improving brain bioavailability. In particular, solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) have been a focus of research related to drug delivery to the brain. These systems provide protection of lipophilic drugs, improved delivery and bioavailability, having a major impact on treatments outcomes. In addition, the use of lipid nanoparticles administered via routes that transport drugs directly into the brain seems a promising solution to avoid the difficulties in crossing the BBB. For instance, the nose-to-brain route has gained considerable interest, as it has shown efficacy in 3D human nasal models and in animal models. This review addresses the state of the art on the use of lipid nanoparticles to modify the pharmacokinetics of drugs employed in the management of neurological disorders. A description of the structural components of the BBB, the role of the neurovascular unit and limitations for drugs to entry into the CNS is first addressed, along with the developments to increase drug delivery to the brain, with a special focus on lipid nanoparticles. In addition, the obstacle of BBB complexity in the creation of new effective drugs for the treatment of the most prevalent neurological disorders is also addressed. Finally, the proposed strategies for lipid nanoparticles to reach the CNS, crossing or circumventing the BBB, are described. Although promising results have been reported, especially with the nose-to-brain route, they are still ongoing to assess its real efficacy in vivo in the management of neurological disorders.

Exploring the role of nanomedicines for the therapeutic approach of central nervous system dysfunction: At a glance

In recent decades, research scientists, molecular biologists, and pharmacologists have placed a strong emphasis on cutting-edge nanostructured materials technologies to increase medicine delivery to the central nervous system (CNS). The application of nanoscience for the treatment of neurodegenerative diseases (NDs) such as Alzheimer’s disease (AD), Parkinson’s disease (PD), multiple sclerosis (MS), Huntington’s disease (HD), brain cancer, and hemorrhage has the potential to transform care. Multiple studies have indicated that nanomaterials can be used to successfully treat CNS disorders in the case of neurodegeneration. Nanomedicine development for the cure of degenerative and inflammatory diseases of the nervous system is critical. Nanoparticles may act as a drug transporter that can precisely target sick brain sub-regions, boosting therapy success. It is important to develop strategies that can penetrate the blood–brain barrier (BBB) and improve the effectiveness of medications. One of the probable tactics is the use of different nanoscale materials. These nano-based pharmaceuticals offer low toxicity, tailored delivery, high stability, and drug loading capacity. They may also increase therapeutic effectiveness. A few examples of the many different kinds and forms of nanomaterials that have been widely employed to treat neurological diseases include quantum dots, dendrimers, metallic nanoparticles, polymeric nanoparticles, carbon nanotubes, liposomes, and micelles. These unique qualities, including sensitivity, selectivity, and ability to traverse the BBB when employed in nano-sized particles, make these nanoparticles useful for imaging studies and treatment of NDs. Multifunctional nanoparticles carrying pharmacological medications serve two purposes: they improve medication distribution while also enabling cell dynamics imaging and pharmacokinetic study. However, because of the potential for wide-ranging clinical implications, safety concerns persist, limiting any potential for translation. The evidence for using nanotechnology to create drug delivery systems that could pass across the BBB and deliver therapeutic chemicals to CNS was examined in this study.

Signature Effects of Vector-Guided Systemic Nano Bioconjugate Delivery Across Blood-Brain Barrier of Normal, Alzheimer's, and Tumor Mouse Models

The ability to cross the blood-brain barrier (BBB) is critical for targeted therapy of the central nerve system (CNS). Six peptide vectors were covalently attached to a 50 kDa poly(β-l-malic acid)-trileucine polymer forming P/LLL(40%)/vector conjugates. The vectors were Angiopep-2 (AP2), B6, Miniap-4 (M4), and d-configurated peptides D1, D3, and ACI-89, with specificity for transcytosis receptors low-density lipoprotein receptor-related protein-1 (LRP-1), transferrin receptor (TfR), bee venom-derived ion channel, and Aβ/LRP-1 related transcytosis complex, respectively. The BBB-permeation efficacies were substantially increased ("boosted") in vector conjugates of P/LLL(40%). We have found that the copolymer group binds at the endothelial membrane and, by an allosterically membrane rearrangement, exposes the sites for vector-receptor complex formation. The specificity of vectors is indicated by competition experiments with nonconjugated vectors. P/LLL(40%) does not function as an inhibitor, suggesting that the copolymer binding site is eliminated after binding of the vector-nanoconjugate. The two-step mechanism, binding to endothelial membrane and allosteric exposure of transcytosis receptors, is supposed to be an integral feature of nanoconjugate-transcytosis pathways. In vivo brain delivery signatures of the nanoconjugates were recapitulated in mouse brains of normal, tumor (glioblastoma), and Alzheimer's disease (AD) models. BBB permeation of the tumor was most efficient, followed by normal and then AD-like brain. In tumor-bearing and normal brains, AP2 was the top performing vector; however, in AD models, D3 and D1 peptides were superior ones. The TfR vector B6 was equally efficient in normal and AD-model brains. Cross-permeation efficacies are manifested through modulated vector coligation and dosage escalation such as supra-linear dose dependence and crossover transcytosis activities.

Innovative treatments for epilepsy: Venom peptides, cannabinoids, and neurostimulation

Antiepileptic drugs have been successfully treating epilepsy and providing individuals sustained seizure freedom. However, about 30% of the patients with epilepsy present drug resistance, which means they are not responsive to the pharmacological treatment. Considering this, it becomes extremely relevant to pursue alternative therapeutic approaches, in order to provide appropriate treatment for those patients and also improve their quality of life. In the light of that, this review aims to discuss some innovative options for the treatment of epilepsy, which are currently under investigation, addressing strategies that go from therapeutic compounds to clinical procedures. For instance, peptides derived from animal venoms, such as wasps, spiders, and scorpions, demonstrate to be promising antiepileptic molecules, acting on a variety of targets. Other options are cannabinoids and compounds that modulate the endocannabinoid system, since it is now known that this network is involved in the pathophysiology of epilepsy. Furthermore, neurostimulation is another strategy, being an alternative clinical procedure for drug-resistant patients who are not eligible for palliative surgeries.

Surface Engineered Dendrimers: A Potential Nanocarrier for the Effective Management of Glioblastoma Multiforme

Gliomas are the most prevailing intracranial tumors, which account for approximately 36% of the primary brain tumors of glial cells. Glioblastoma multiforme (GBM) possesses a higher degree of malignancy among different gliomas. The blood-brain barrier (BBB) protects the brain against infections and toxic substances by preventing foreign molecules or unwanted cells from entering the brain parenchyma. Nano-carriers such as liposomes, nanoparticles, dendrimers, etc. boost the brain permeability of various anticancer drugs or other drugs. The favorable properties like small size, better solubility, and the modifiable surface of dendrimers have proven their broad applicability in the better management of GBM. However, in vitro and in vivo toxicities caused by dendrimers have been a significant concern. The presence of multiple functionalities on the surface of dendrimers enables the grafting of target ligand and/or therapeutic moieties. Surface engineering improves certain properties like targeting efficiency, pharmacokinetic profile, therapeutic effect, and toxicity reduction. This review will be focused on the role of different surface-modified dendrimers in the effective management of GBM.

Nanogels as Novel Nanocarrier Systems for Efficient Delivery of CNS Therapeutics

Nanogels have come out as a great potential drug delivery platform due to its prominently high colloidal stability, high drug loading, core-shell structure, good permeation property and can be responsive to environmental stimuli. Such nanoscopic drug carriers have more excellent abilities over conventional nanomaterials for permeating to brain parenchyma in vitro and in vivo. Nanogel-based system can be nanoengineered to bypass physiological barriers via non-invasive treatment, rendering it a most suitable platform for the management of neurological conditions such as neurodegenerative disorders, brain tumors, epilepsy and ischemic stroke, etc. Therapeutics of central nervous system (CNS) diseases have shown marked limited site-specific delivery of CNS by the poor access of various drugs into the brain, due to the presences of the blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCSFB). Hence, the availability of therapeutics delivery strategies is considered as one of the most major challenges facing the treatment of CNS diseases. The primary objective of this review is to elaborate the newer advances of nanogel for CNS drugs delivery, discuss the early preclinical success in the field of nanogel technology and highlight different insights on its potential neurotoxicity.

Comparison of Tau and Amyloid-β Targeted Immunotherapy Nanoparticles for Alzheimer’s Disease

Alzheimer’s disease (AD) is a rapidly growing global concern associated with the accumulation of amyloid-β plaques and intracellular neurofibrillary tangles in the brain combined with a high acetylcholinesterase activity. AD diagnosis is usually made too late, when patients have an extensive neuronal death, and brain damage is irreversible. Several therapeutic targets have been defined mainly related to two hypotheses of AD: the tau hypothesis and the amyloid-β hypothesis. Here, we intend to investigate and to compare different therapeutic approaches for AD, mainly based on nanoparticles (NPs) targeted at the brain and at the pathological hallmarks of the disease. We analyzed preclinical trials that have successfully improved drug bioavailability in the brain by using targeted nanocarriers towards either tau, amyloid-β, or both. We then compared these trials to find out which protein is more efficient in therapeutic targeting. We found that the search for a cure was mostly based on the amyloid-β hypothesis, with Aβ dysplasia emerging as the most confirmed and convincing therapeutic target. Targeted NPs have proven useful to enhance both the bioavailability and the performance of therapies against AD in animal models. A better understanding of AD mechanisms will help the successful application of targeted NPs for combined therapies.

Non-small molecule PROTACs (NSM-PROTACs): Protein degradation kaleidoscope

The proteolysis targeting chimeras (PROTACs) technology has been rapidly developed since its birth in 2001, attracting rapidly growing attention of scientific institutes and pharmaceutical companies. At present, a variety of small molecule PROTACs have entered the clinical trial. However, as small molecule PROTACs flourish, non-small molecule PROTACs (NSM-PROTACs) such as peptide PROTACs, nucleic acid PROTACs and antibody PROTACs have also advanced considerably over recent years, exhibiting the unique characters beyond the small molecule PROTACs. Here, we briefly introduce the types of NSM-PROTACs, describe the advantages of NSM-PROTACs, and summarize the development of NSM-PROTACs so far in detail. We hope this article could not only provide useful insights into NSM-PROTACs, but also expand the research interest of NSM-PROTACs.

Neuropathogenesis of HIV and emerging therapeutic targets

INTRODUCTION

HIV infection causes a wide range of neurological complications, many of which are among the most common complications of chronic HIV infection in the era of combined antiretroviral therapy. These neurological conditions arise due to complex interactions between HIV viral proteins and neuronal and glial cells that lead to the activation of various inflammatory and neurotoxic pathways across the nervous system.

AREAS COVERED

This review summarizes the current literature on the pathogenesis and clinical manifestations of neurological injuries associated with HIV in the brain, spinal cord, and peripheral nervous system. Molecular pathways relevant for possible therapeutic targets or advancements are emphasized. Gaps in knowledge and current challenges in therapeutic design are also discussed.

EXPERT OPINION

Several challenges exist in the development of therapeutic targets for HIV-associated cognitive impairments. However, recent developments in drug delivery systems and treatment strategies are encouraging. Treatments for HIV-associated pain and peripheral sensory neuropathies currently consist of symptomatic management, but a greater understanding of their pathogenesis can lead to the development of targeted molecular therapies and disease-modifying therapies. HIV-associated autonomic dysfunction may affect the course of systemic disease via disrupted neuro-immune interactions; however, more research is needed to facilitate our understanding of how these processes present clinically.

An Overview of the Neuropharmacological Potential of Thymoquinone and its Targeted Delivery Prospects for CNS Disorder

At present, people and patients worldwide are relying on the medicinal plant as a therapeutic agent over pharmaceuticals because the medicinal plant is considered safer, especially for chronic disorders. Several medicinal plants and their components are being researched and explored for their possible therapeutic contribution to CNS disorders. Thymoquinone (TQ) is one such molecule. Thymoquinone, one of the constituents of Plant Nigella Sativa, is effective against several neurodegenerative diseases like; Alzheimer's, Depression, Encephalomyelitis, Epilepsy, Ischemia, Parkinson's, and Traumatic. This review article presents the neuropharmacological potential of TQ's, their challenges, and delivery prospects, explicitly focusing on neurological disorders along with their chemistry, pharmacokinetics, and toxicity. Since TQ has some pharmacokinetic challenges, scientists have focused on novel formulations and delivery systems to enhance bioavailability and ultimately increase its therapeutic value. In the present work, the role of nanotechnology in neurodegenerative disease and how it improves bioavailability and delivery of a drug to the site of action has been discussed. There are a few limitations for developing novel drug formulation, including solubility, pH, and compatibility of nanomaterials. Since here we are targeting CNS disorders, the blood-brain barrier (BBB) becomes an additional challenge Hence, the review summarized the novel aspects of delivery and biocompatible nanoparticles-based approaches for targeted drug delivery into CNS, enhancing TQ bioavailability and its neurotherapeutic effects.

Advances in Nanomedicine Design: Multidisciplinary Strategies for Unmet Medical Needs

Globally, a rising burden of complex diseases takes a heavy toll on human lives and poses substantial clinical and economic challenges. This review covers nanomedicine and nanotechnology-enabled advanced drug delivery systems (DDS) designed to address various unmet medical needs. Key nanomedicine and DDSs, currently employed in the clinic to tackle some of these diseases, are discussed focusing on their versatility in diagnostics, anticancer therapy, and diabetes management. First-hand experiences from our own laboratory and the work of others are presented to provide insights into strategies to design and optimize nanomedicine- and nanotechnology-enabled DDS for enhancing therapeutic outcomes. Computational analysis is also briefly reviewed as a technology for rational design of controlled release DDS. Further explorations of DDS have illuminated the interplay of physiological barriers and their impact on DDS. It is demonstrated how such delivery systems can overcome these barriers for enhanced therapeutic efficacy and how new perspectives of next-generation DDS can be applied clinically.

Targeted Delivery Platforms for the Treatment of Multiple Sclerosis

Multiple sclerosis (MS) is a neurodegenerative condition of the central nervous system (CNS) that presents with varying levels of disability in patients, displaying the significance of timely and effective management of this complication. Though several treatments have been developed to protect nerves, comprehensive improvement of MS is still considered an essential bottleneck. Therefore, the development of innovative treatment methods for MS is one of the core research areas. In this regard, nanoscale platforms can offer practical and ideal approaches to the diagnosis and treatment of various diseases, especially immunological disorders such as MS, to improve the effectiveness of conventional therapies. It should be noted that there is significant progress in the development of neuroprotective strategies through the implementation of various nanoparticles, monoclonal antibodies, peptides, and aptamers. In this study, we summarize different particle systems as well as targeted therapies, such as antibodies, peptides, nucleic acids, and engineered cells for the treatment of MS, and discuss their potential in the treatment of MS in the preclinical and clinical stages. Future advances in targeted delivery of medical supplies may offer new strategies for complete recovery as well as practical treatment of progressive forms of MS.

Therapeutic Opportunities and Delivery Strategies for Brain Revascularization in Stroke, Neurodegeneration, and Aging

Central nervous system (CNS) diseases, especially acute ischemic events and neurodegenerative disorders, constitute a public health problem with no effective treatments to allow a persistent solution. Failed therapies targeting neuronal recovery have revealed the multifactorial and intricate pathophysiology underlying such CNS disorders as ischemic stroke, Alzheimeŕs disease, amyotrophic lateral sclerosis, vascular Parkisonism, vascular dementia, and aging, in which cerebral microvasculature impairment seems to play a key role. In fact, a reduction in vessel density and cerebral blood flow occurs in these scenarios, contributing to neuronal dysfunction and leading to loss of cognitive function. In this review, we provide an overview of healthy brain microvasculature structure and function in health and the effect of the aforementioned cerebral CNS diseases. We discuss the emerging new therapeutic opportunities, and their delivery approaches, aimed at recovering brain vascularization in this context. SIGNIFICANCE STATEMENT: The lack of effective treatments, mainly focused on neuron recovery, has prompted the search of other therapies to treat cerebral central nervous system diseases. The disruption and degeneration of cerebral microvasculature has been evidenced in neurodegenerative diseases, stroke, and aging, constituting a potential target for restoring vascularization, neuronal functioning, and cognitive capacities by the development of therapeutic pro-angiogenic strategies.

Donepezil HCl Liposomes: Development, Characterization, Cytotoxicity, and Pharmacokinetic Study

The current research work aims to study the pharmacokinetic and nasal ciliotoxicity of donepezil liposome-based in situ gel to treat Alzheimer's disease. The physicochemical properties and first-pass metabolism of donepezil HCl result in low concentrations reaching the brain post oral administration. To overcome this problem, donepezil HCl-loaded liposomes were formulated using the ethanol injection method. The donepezil HCl-loaded liposomes were spherical with a size of 103 ± 6.2 nm, polydispersity index of 0.108 ± 0.008, and entrapment efficiency of 93 ± 5.33 %. The optimized in situ gel with donepezil HCl-loaded liposomes showed 80.11 ± 7.77 % drug permeation than donepezil HCl solution-based in situ gel (13.12 ± 4.84 %) across sheep nasal mucosa. The nasal ciliotoxicity study indicated the safety of developed formulation for administration via nasal route. The pharmacokinetics and biodistribution study of developed formulation showed higher drug concentration (1239.61 ± 123.60 pg/g) in the brain after nasal administration indicating its better potential via the nasal pathway. To treat Alzheimer's disease, the administration of liposome-based in situ gel through the nasal pathway can therefore be considered as an effective and promising mode of drug delivery.

Potential innovation against Alzheimer's disorder: a tricomponent combination of natural antioxidants (vitamin E, quercetin, and basil oil) and the development of its intranasal delivery

Alzheimer's disorder (AD) is very difficult to manage and treat. The complexity of the brain, the blood-brain barrier influencing a multitude of parameters/biomarkers, as well as numerous other factors involved often contribute to the decline in the chances of treatment success. Development of the new drug moiety also takes time, being necessary to consider both its toxicity and related issues. As a strategic plan, a combined strategy is being developed and considered to address AD pathology using several approaches. A combination of vitamin E, quercetin, and basil oil in a nano-based formulation is designed to be administered nasally. The antioxidant present in these natural-based products helps to treat and alleviate AD if a synergistic approach is considered. The three active substances mentioned above are well known for the treatment of neurodegenerative disorders. The nanoformulation helps the co-delivery of the drug moiety to the brain through the intranasal route. In this review, a correlation and use of vitamin E, quercetin, and basil oil in a nano-based formulation is described as an effective way to treat AD. The intranasal administration of drugs is a promising approach for the treatment of neurodegenerative and mental disorders, as this route is non-invasive, enhances the bioavailability, allows a drug dose reduction, bypasses the blood-brain barrier, and reduces the systemic undesired effect. The use of natural products is generally considered to be just as safe; therefore, by using this combined approach, the level of toxicity can be minimized.

Alzheimer's Disease: Pathogenesis and Therapeutic Interventions

BACKGROUND

Alzheimer's Disease (AD) is the most common cause of dementia. Genetics, excessive exposure to environmental pollutants, as well as unhealthy lifestyle practices are often linked to the development of AD. No therapeutic approach has achieved complete success in treating AD; however, early detection and management with appropriate drugs are key to improving prognosis.

INTERVENTIONS

The pathogenesis of AD was extensively discussed in order to understand the reasons for the interventions suggested. The interventions reviewed include the use of different therapeutic agents and approaches, gene therapy, adherence to healthy dietary plans (Mediterranean diet, Okinawan diet and MIND diet), as well as the use of medicinal plants. The potential of nanotechnology as a multidisciplinary and interdisciplinary approach in the design of nano-formulations of AD drugs and the use of Superparamagnetic Iron Oxide Nanoparticles (SPIONs) as theranostic tools for early detection of Alzheimer's disease were also discussed.

Nanotechnology-based drug delivery for the treatment of CNS disorders

Approximately 6.8 million people die annually because of problems related to the central nervous system (CNS), and out of them, approximately 1 million people are affected by neurodegenerative diseases that include Alzheimer's disease, multiple sclerosis, epilepsy, and Parkinson's disease. CNS problems are a primary concern because of the complexity of the brain. There are various drugs available to treat CNS disorders and overcome problems with toxicity, specificity, and delivery. Barriers like the blood-brain barrier (BBB) are a challenge, as they do not allow therapeutic drugs to cross and reach their target. Researchers have been searching for ways to allow drugs to pass through the BBB and reach the target sites. These problems highlight the need of nanotechnology to alter or manipulate various processes at the cellular level to achieve the desired attributes. Due to their nanosize, nanoparticles are able to pass through the BBB and are an effective alternative to drug administration and other approaches. Nanotechnology has the potential to improve treatment and diagnostic techniques for CNS disorders and facilitate effective drug transfer. With the aid of nanoengineering, drugs could be modified to perform functions like transference across the BBB, altering signaling pathways, targeting specific cells, effective gene transfer, and promoting regeneration and preservation of nerve cells. The involvement of a nanocarrier framework inside the delivery of several neurotherapeutic agents used in the treatment of neurological diseases is reviewed in this study.

Advances in the research of nano delivery systems in ischemic stroke

Ischemic stroke is the most common type of cerebrovascular disease with high disability rate and mortality. The blood-brain barrier (BBB) protects the homeostasis of the brain's microenvironment and impedes the penetration of 98% of drugs. Therefore, effective treatment requires the better drug transport across membranes and increased drug distribution. Nanoparticles are a good choice for drugs to cross BBB. The main pathways of nano delivery systems through BBB include passive diffusion, adsorption-mediated endocytosis, receptor-mediated transport, carrier-mediated transport, etc. At present, the materials used in brain-targeted delivery can be divided into natural polymer, synthetic polymers, inorganic materials and phospholipid. In this review, we first introduced several ways of nano delivery systems crossing the BBB, and then summarized their applications in ischemic stroke. Based on their potential and challenges in the treatment of ischemic stroke, new ideas and prospects are proposed for designing feasible and effective nano delivery systems.

Human hepatitis B virus-derived virus-like particle as a drug and DNA delivery carrier

The controlled release of medications using nanoparticle-based drug delivery carriers is a promising method to increase the efficacy of pharmacotherapy and gene therapy. One critical issue that needs to be overcome with these drug delivery carriers is their target specificity. We focused on the cell tropism of a virus to solve this issue, i.e., we attempted to apply hepatitis B virus-like particle (HBV-VLP) as a novel hepatic cell-selective carrier for medication and DNA. To prepare HBV-VLP, 293T cells were transfected with expression plasmids carrying HBV envelope surface proteins, large envelope protein (L), and small envelope protein (S). After 72 h post-transfection, VLP-containing culture supernatants were harvested, and HBV-VLP was labeled with red fluorescent dye (DiI) and was purified by sucrose gradient ultracentrifugation. An anticancer drugs (geldanamycin or doxorubicin) and GFP-expressing plasmid DNA were incorporated into HBV-VLP, and medication- and plasmid DNA-loaded VLPs were prepared. We evaluated their delivery capabilities into hepatocytes, other organ-derived cells, and hepatocytes expressing sodium taurocholate cotransporting polypeptide (NTCP), which functions as the cellular receptor for HBV by binding to HBV L protein. HBV-VLP selectively delivered both anticancer drugs and plasmid DNA not into HepG2, Huh7, and other organ cells but into HepG2 cells expressing NTCP. In summary, we developed a novel delivery nanocarrier using HBV-VLP that could be used as a hepatitis selective drug- and DNA-carrier for cancer treatment and gene therapy.

The Dynamic Interactions between Nanoparticles and Macrophages Impact Their Fate in Brain Tumors

Functional nanomaterials such as iron oxide nanoparticles have been extensively explored for the diagnosis and treatment of central nervous system diseases. However, an insufficient understanding of the comprehensive nanomaterial-biological interactions in the brain hinders the nanomaterials from meeting the medical requirements for translational research. Here, FDA-approved ferumoxytol, an iron oxide nanoparticle, is chosen as the model nanomaterial for a systematic study of the dynamic interactions between ferumoxytol and immune cells, including microglia and macrophages, in the brain tumors. Strikingly, up to 90% of intratumorally injected ferumoxytol nanoparticles are recognized and phagocytized by tumor-associated microglia and macrophages. The dynamic trafficking progress of ferumoxytol in microglia and macrophages, including scavenger receptor-mediated endocytosis, lysosomal internalization, and extracellular vesicle-dominated excretion, is further studied. Importantly, the results demonstrate that extracellular vesicle-encapsulated nanoparticles could be gradually eliminated from the brain along with cerebrospinal fluid circulation over 21 days. Moreover, ferumoxytol exhibits no obvious long-term neurological toxicity after its injection. The study suggests that the dynamic biointeractions of nanoparticles with immune cells in the brain exert a key rate-limiting impact on the efficiency of targeting tumor cells and their in vivo fate and thus provide a deeper understanding of the nanomaterials in the brain for clinical applications.

Mechanisms Involved in Microglial-Interceded Alzheimer's Disease and Nanocarrier-Based Treatment Approaches

Alzheimer's disease (AD) is a common neurodegenerative disorder accountable for dementia and cognitive dysfunction. The etiology of AD is complex and multifactorial in origin. The formation and deposition of amyloid-beta (Aβ), hyperphosphorylated tau protein, neuroinflammation, persistent oxidative stress, and alteration in signaling pathways have been extensively explored among the various etiological hallmarks. However, more recently, the immunogenic regulation of AD has been identified, and macroglial activation is considered a limiting factor in its etiological cascade. Macroglial activation causes neuroinflammation via modulation of the NLRP3/NF-kB/p38 MAPKs pathway and is also involved in tau pathology via modulation of the GSK-3β/p38 MAPK pathways. Additionally, microglial activation contributes to the discrete release of neurotransmitters and an altered neuronal synaptic plasticity. Therefore, activated microglial cells appear to be an emerging target for managing and treating AD. This review article discussed the pathology of microglial activation in AD and the role of various nanocarrier-based anti-Alzeihmenr's therapeutic approaches that can either reverse or inhibit this activation. Thus, as a targeted drug delivery system, nanocarrier approaches could emerge as a novel means to overcome existing AD therapy limitations.

Optimizing the Design of Blood-Brain Barrier-Penetrating Polymer-Lipid-Hybrid Nanoparticles for Delivering Anticancer Drugs to Glioblastoma

PURPOSE

Chemotherapy for glioblastoma multiforme (GBM) remains ineffective due to insufficient penetration of therapeutic agents across the blood-brain barrier (BBB) and into the GBM tumor. Herein, is described, the optimization of the lipid composition and fabrication conditions for a BBB- and tumor penetrating terpolymer-lipid-hybrid nanoparticle (TPLN) for delivering doxorubicin (DOX) to GBM.

METHODS

The composition of TPLNs was first screened using different lipids based on nanoparticle properties and in vitro cytotoxicity by using 2³ full factorial experimental design. The leading DOX loaded TPLNs (DOX-TPLN) were prepared by further optimization of conditions and used to study cellular uptake mechanisms, in vitro cytotoxicity, three-dimensional (3D) glioma spheroid penetration, and in vivo biodistribution in a murine orthotopic GBM model.

RESULTS

Among various lipids studied, ethyl arachidate (EA) was found to provide excellent nanoparticle properties e.g., size, polydispersity index (PDI), zeta potential, encapsulation efficiency, drug loading, and colloidal stability, and highest anticancer efficacy for DOX-TPLN. Further optimized EA-based TPLNs were prepared with an optimal particle size (103.8 ± 33.4 nm) and PDI (0.208 ± 0.02). The resultant DOX-TPLNs showed ~ sevenfold higher efficacy than free DOX against human GBM U87-MG-RED-FLuc cells in vitro. The interaction between the TPLNs and the low-density lipoprotein receptors also facilitated cellular uptake, deep penetration into 3D glioma spheroids, and accumulation into the in vivo brain tumor regions of DOX-TPLNs.

CONCLUSION

This work demonstrated that the TPLN system can be optimized by rational selection of lipid type, lipid content, and preparation conditions to obtain DOX-TPLN with enhanced anticancer efficacy and GBM penetration and accumulation.

Perspective Insights to Bio-Nanomaterials for the Treatment of Neurological Disorders

The significance of biomaterials is well appreciated in nanotechnology, and its use has resulted in major advances in biomedical sciences. Although, currently, very little data is available on the clinical trial studies for treatment of neurological conditions, numerous promising advancements have been reported in drug delivery and regenerative therapies which can be applied in clinical practice. Among the commonly reported biomaterials in literature, the self-assembling peptides and hydrogels have been recognized as the most potential candidate for treatment of common neurological conditions such as Alzheimer's, Parkinson's, spinal cord injury, stroke and tumors. The hydrogels, specifically, offer advantages like flexibility and porosity, and mimics the properties of the extracellular matrix of the central nervous system. These factors make them an ideal scaffold for drug delivery through the blood-brain barrier and tissue regeneration (using stem cells). Thus, the use of biomaterials as suitable matrix for therapeutic purposes has emerged as a promising area of neurosciences. In this review, we describe the application of biomaterials, and the current advances, in treatment of statistically common neurological disorders.