Nanotechnology-novel therapeutics for CNS disorders

Intranasal Delivery of Cell-Penetrating Therapeutic Peptide Enhances Brain Delivery, Reduces Inflammation, and Improves Neurologic Function in Moderate Traumatic Brain Injury

Following traumatic brain injury (TBI), secondary brain damage due to chronic inflammation is the most predominant cause of the delayed onset of mood and memory disorders. Currently no therapeutic approach is available to effectively mitigate secondary brain injury after TBI. One reason is the blood-brain barrier (BBB), which prevents the passage of most therapeutic agents into the brain. Peptides have been among the leading candidates for CNS therapy due to their low immunogenicity and toxicity, bioavailability, and ease of modification. In this study, we demonstrated that non-invasive intranasal (IN) administration of KAFAK, a cell penetrating anti-inflammatory peptide, traversed the BBB in a murine model of diffuse, moderate TBI. Notably, KAFAK treatment reduced the production of proinflammatory cytokines that contribute to secondary injury. Furthermore, behavioral tests showed improved or restored neurological, memory, and locomotor performance after TBI in KAFAK-treated mice. This study demonstrates KAFAK's ability to cross the blood-brain barrier, to lower proinflammatory cytokines in vivo, and to restore function after a moderate TBI.

Recent advances of focused ultrasound induced blood-brain barrier opening for clinical applications of neurodegenerative diseases

With the aging population on the rise, neurodegenerative disorders have taken center stage as a significant health concern. The blood-brain barrier (BBB) plays an important role to maintain the stability of central nervous system, yet it poses a formidable obstacle to delivering drugs for neurodegenerative disease therapy. Various methods have been devised to confront this challenge, each carrying its own set of limitations. One particularly promising noninvasive approach involves the utilization of focused ultrasound (FUS) combined with contrast agents-microbubbles (MBs) to achieve transient and reversible BBB opening. This review provides a comprehensive exploration of the fundamental mechanisms behind FUS/MBs-mediated BBB opening and spotlights recent breakthroughs in its application for neurodegenerative diseases. Furthermore, it addresses the current challenges and presents future perspectives in this field.

Risperidone-Loaded Nasal Thermosensitive Polymeric Micelles: Quality by Design-Based Formulation Study

The current research aims to develop thermosensitive polymeric micelles loaded with risperidone for nasal administration, emphasizing the added benefits of their thermosensitive behavior under nasal conditions. An initial risk assessment facilitated the advanced development process, confirming that the key indicators of thermosensitivity were suitable for nasal application. The polymeric micelles exhibited an average size of 118.4 ± 3.1 nm at ambient temperature and a size of 20.47 ± 1.2 nm at 36.5 °C, in both cases in monodisperse distribution. Factors such as pH and viscosity did not significantly impact these parameters, demonstrating appropriate nasal applicability. The model formulations showed a rapid, burst-like drug release profile in vitro, accompanied by a quick and high permeation rate at nasal conditions. Overall, the Quality by Design-based risk assessment process led to the development of an advanced drug delivery system capable of administering risperidone through the nasal cavity.

The potential of graphene coatings as neural interfaces

Recent advances in nanotechnology design and fabrication have shaped the landscape for the development of ideal cell interfaces based on biomaterials. A holistic evaluation of the requirements for a cell interface is a highly complex task. Biocompatibility is a crucial requirement which is affected by the interface's properties, including elemental composition, morphology, and surface chemistry. This review explores the current state-of-the-art on graphene coatings produced by chemical vapor deposition (CVD) and applied as neural interfaces, detailing the key properties required to design an interface capable of physiologically interacting with neural cells. The interfaces are classified into substrates and scaffolds to differentiate the planar and three-dimensional environments where the cells can adhere and proliferate. The role of specific features such as mechanical properties, porosity and wettability are investigated. We further report on the specific brain-interface applications where CVD graphene paved the way to revolutionary advances in biomedicine. Future studies on the long-term effects of graphene-based materials in vivo will unlock even more potentially disruptive neuro-applications.

Tumor microenvironment targeting for glioblastoma multiforme treatment via hybrid cell membrane coating supramolecular micelles

Glioblastoma multiforme (GBM) is one of the most common primary intracranial tumors in the central nervous system with poor prognosis, high invasiveness, risk of recurrence and low survival rate. Thus, it is urgent and vital to develop drug effective delivery systems that efficiently to traverse the blood-brain barrier and targeted transport therapeutic agents into the GBM tumor site for the treatment of brain tumors. Recently, amphiphilic cucurbit[7]uril-polyethylene glycol-hydrophobic Chlorin e6 (CB[7]-PEG-Ce6) polymer was designed, prepared, and self-assembled into micells (CPC) in an aqueous solution, and chemo drug methyl-triazeno-imidazole-carboxamide (MTIC), loaded into the cavity of CB[7] was subsequently coated with hybrid membrane mUMH (HMC3 membrane: macrophage membrane: U87MG membrane = 1:1:2) to afford mUMH@CPC@MTIC. The surface hybrid membrane mUMH potentially enhance the targeted delivery of CPC@MTIC to GBM tissue. Bioactive MTIC was released from the cavity of CB[7] in response to the high spermine level in GBM tumor microenvironments for effective tumor chemotherapy. The biomimetic mUMH@CPC@MTIC exhibited superior antitumor efficacy against GBM in mice. These findings provide new strategies for the design of biomimetic nanoparticle-based drug delivery systems and promising therapy of GBM.

Protein Nanotubes as Advanced Material Platforms and Delivery Systems

Protein nanotubes (PNTs) as state-of-the-art nanocarriers are promising for various potential applications both in the food and pharmaceutical industries. Derived from edible starting sources like α-lactalbumin, lysozyme, and ovalbumin, PNTs bear properties of biocompatibility and biodegradability. Their large specific surface area and hydrophobic core facilitate chemical modification and loading of bioactive substances, respectively. Moreover, their enhanced permeability and penetration ability across biological barriers such as intestinal mucus, extracellular matrix, and thrombus clot, make it promising platforms for health-related applications. Most importantly, their simple preparation processes enable large-scale production, supporting applications in the biomedical and nanotechnological fields. Understanding the self-assembly principles is crucial for controlling their morphology, size, and shape, and thus provides the ground to a multitude of applications. Here, the current state-of-the-art of PNTs including their building materials, physicochemical properties, and self-assembly mechanisms are comprehensively reviewed. The advantages and limitations, as well as challenges and prospects for their successful applications in biomaterial and pharmaceutical sectors are then discussed and highlighted. Potential cytotoxicity of PNTs and the need of regulations as critical factors for enabling in vivo applications are also highlighted. In the end, a brief summary and future prospects for PNTs as advanced platforms and delivery systems are included.

Conformation and vibrational spectroscopic analysis of 2,6-bis(4-fluorophenyl)-3,3-dimethylpiperidin-4-one (BFDP) by DFT method: A potent anti-Parkinson's, anti-lung cancer, and anti-human infectious agent

The potential of 2,6-bis(4-fluorophenyl)-3,3-dimethylpiperidin-4-one (BFDP) as an anti-Parkinson's, anti-lung cancer, and anti-human infectious agent was extensively assessed in the current study. To accomplish this, the compound BFDP was synthesised and analysed using several spectroscopic approaches, such as NMR, mass and FT-IR spectral studies. The computational calculations for the molecule were carried out using density functional theory (DFT) at the B3LYP/6-311G++ (d,p) level of theory. A X-ray diffraction (XRD) study allows us to analyse the crystalline structure of our BFDP molecule. Intermolecular interactions were assessed using 3D Hirshfeld surfaces (3D-HS) and 2D fingerprint plots. AIM and NCI-RDG were done using quantum calculations and the DFT technique, and topological ELF and LOL, as well as vibrational parameters, have been obtained. The thermodynamic and thermal properties of the BFDP compound were determined. To investigate the pharmacokinetic characteristics of BFDP, a molecular docking study and an in silico ADMET study were done.

Advances of nanotechnology for intracerebral hemorrhage therapy

Intracerebral hemorrhage (ICH), the most devastating subtype of stoke, is of high mortality at 5 years and even those survivors usually would suffer permanent disabilities. Fortunately, various preclinical active drugs have been approached in ICH, meanwhile, the therapeutic effects of these pharmaceutical ingredients could be fully boosted with the assistance of nanotechnology. In this review, besides the pathology of ICH, some ICH therapeutically available active drugs and their employed nanotechnologies, material functions, and therapeutic principles were comprehensively discussed hoping to provide novel and efficient strategies for ICH therapy in the future.

Targeting multifunctional magnetic nanowires for drug delivery in cancer cell death: an emerging paradigm

Apoptosis, often known as programmed cell death is a mechanism used by numerous species to maintain tissue homeostasis. The process leading to cell death is complicated because it requires the stimulation of caspases. According to several studies, nanowires have important medical benefits, can kill cells by adhering to cancer cells, destroying them, and killing the entire cell using a triple attack that integrates vibration, heat, and drug delivery to trigger apoptosis. The sewage effluents and industrial, fertilizer and organic wastes decomposition can produce elevated levels of chemicals in the environment which may interrupt the cell cycle and activate apoptosis. The purpose of this review is to give a thorough summary of the evidence that is currently available on apoptosis. Current review discussed topics like the morphological and biochemical alterations that occur during apoptosis, as well as the various mechanisms that cause cell death, including the intrinsic (or mitochondrial), extrinsic (or death receptor), and intrinsic endoplasmic reticulum pathway. The apoptosis reduction in cancer development is mediated by (i) an imbalance between pro- and anti-apoptotic proteins, such as members of the B-cell lymphoma-2 (BCL2) family of proteins, tumour protein 53 and inhibitor of apoptosis proteins, (ii) a reduction in caspase activity, and (iii) impaired death receptor signalling. This review does an excellent task of outlining the function of nanowires in both apoptosis induction and targeted drug delivery for cancer cells. A comprehensive summary of the relevance of nanowires synthesised for the purpose of inducing apoptosis in cancer cells has been compiled collectively.

Insights into the promising prospect of medicinal chemistry studies against neurodegenerative disorders

Medicinal chemistry is an interdisciplinary field that incorporates organic chemistry, biochemistry, physical chemistry, pharmacology, informatics, molecular biology, structural biology, cell biology, and other disciplines. Additionally, it considers molecular factors such as the mode of action of the drugs, their chemical structure-activity relationship (SAR), and pharmacokinetic aspects like absorption, distribution, metabolism, elimination, and toxicity. Neurodegenerative disorders (NDs), which are defined by the breakdown of neurons over time, are affecting an increasing number of people. Oxidative stress, particularly the increased production of Reactive Oxygen Species (ROS), plays a crucial role in the growth of various disorders, as indicated by the identification of protein, lipid, and Deoxyribonucleic acid (DNA) oxidation products in vivo. Because of their inherent nature, most biological molecules are vulnerable to ROS, even if they play a role in metabolic parameters and cell signaling. Due to their high polyunsaturated fatty acid content, low antioxidant barrier, and high oxygen uptake, neurons are particularly vulnerable to oxidation by nature. As a result, excessive ROS generation in neurons looks especially harmful, and the mechanisms associated with biomolecule oxidative destruction are several and complex. This review focuses on the formation and management of ROS, as well as their chemical characteristics (both thermodynamic and kinetic), interactions, and implications in NDs.

The potential therapeutic value and application prospect of engineered exosomes in human diseases

Exosomes are tiny vesicles produced by a wide range of cells that contain complex RNA and protein. In the diagnosis, treatment, and prevention of illness, they offer great potential. In vitro engineering technique modifies exosomes to produce designed exosomes that include nucleic acids, proteins, and medicines, and are targeted to particular tissues or cells. Their applications range from tumor imaging and gene therapy to vaccine production and regenerative medicine to targeted medication delivery. Many disciplines have promising futures for using this technology. In this review, we'll look at the potential therapeutic usefulness and use of engineered exosomes in a variety of human illnesses with various systemic manifestations.

Diagnostics and theranostics of central nervous system diseases based on aggregation-induced emission luminogens

Central nervous system (CNS) diseases include Alzheimer's disease (AD), Parkinson's disease (PD), brain tumors, strokes, and other important diseases that are harmful and fatal to human beings. CNS diseases have the characteristics of high fatality rates, difficult diagnosis, and costly treatment. The diagnosis and treatment of CNS diseases by molecular imaging are usually limited by the depth of tissue penetration and the blood-brain barrier (BBB). Therefore, it is still a huge challenge to distinguish between the lesion and the surrounding parenchymal boundary with high sensitivity and specificity. Compared with traditional fluorophores with aggregation-caused quenching effect, luminogens with aggregation-induced emission (AIE) characteristics have strong near-infrared deep penetration, large Stokes shift, excellent biocompatibility, light stability, and desirable BBB permeability. In view of this, developing novel AIE-based materials for diagnostics and theranostics of CNS diseases is promising and of great significance. Herein, we highlight the recent research progress in this field with a special focus on near-infrared imaging and AIE nanorobots for CNS diseases. The design principle of AIE probes is discussed in detail, and the outlook is presented as well.

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.

Biomaterials and advanced technologies for the evaluation and treatment of ovarian aging

Ovarian aging is characterized by a progressive decline in ovarian function. With the increase in life expectancy worldwide, ovarian aging has gradually become a key health problem among women. Over the years, various strategies have been developed to preserve fertility in women, while there are currently no clinical treatments to delay ovarian aging. Recently, advances in biomaterials and technologies, such as three-dimensional (3D) printing and microfluidics for the encapsulation of follicles and nanoparticles as delivery systems for drugs, have shown potential to be translational strategies for ovarian aging. This review introduces the research progress on the mechanisms underlying ovarian aging, and summarizes the current state of biomaterials in the evaluation and treatment of ovarian aging, including safety, potential applications, future directions and difficulties in translation.

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.

An update on dual targeting strategy for cancer treatment

The key issue in the treatment of solid tumors is the lack of efficient strategies for the targeted delivery and accumulation of therapeutic cargoes in the tumor microenvironment (TME). Targeting approaches are designed for more efficient delivery of therapeutic agents to cancer cells while minimizing drug toxicity to normal cells and off-targeting effects, while maximizing the eradication of cancer cells. The highly complicated interrelationship between the physicochemical properties of nanoparticles, and the physiological and pathological barriers that are required to cross, dictates the need for the success of targeting strategies. Dual targeting is an approach that uses both purely biological strategies and physicochemical responsive smart delivery strategies to increase the accumulation of nanoparticles within the TME and improve targeting efficiency towards cancer cells. In both approaches, either one single ligand is used for targeting a single receptor on different cells, or two different ligands for targeting two different receptors on the same or different cells. Smart delivery strategies are able to respond to triggers that are typical of specific disease sites, such as pH, certain specific enzymes, or redox conditions. These strategies are expected to lead to more precise targeting and better accumulation of nano-therapeutics. This review describes the classification and principles of dual targeting approaches and critically reviews the efficiency of dual targeting strategies, and the rationale behind the choice of ligands. We focus on new approaches for smart drug delivery in which synthetic and/or biological moieties are attached to nanoparticles by TME-specific responsive linkers and advanced camouflaged nanoparticles.

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.

Where do we stand now regarding treatment of psychiatric and neurodegenerative disorders? Considerations in using magnetoelectric nanoparticles as an innovative approach

Almost 1000 million people have recently been diagnosed with a mental health or substance disorder (Ritchie & Roser, 2018). Psychiatric disorders, and their treatment, represent a big burden to the society worldwide, causing about 8 million deaths per year (Walker et al., 2015). Daily progress in science enables continuous advances in methods to treat patients; however, the brain remains to be the most unknown and complex organ of the body. There is a growing demand for innovative approaches to treat psychiatric as well as neurodegenerative disorders, disorders with unknown curability, and treatments mostly designed to slow disease progression. Based on that need and the peculiarity of the central nervous system, in the present review, we highlight the handicaps of the existing approaches as well as discuss the potential of the recently introduced magnetoelectric nanoparticles (MENPs) to become a game-changing tool in future applications for the treatment of brain alterations. Unlike other stimulation approaches, MENPs have the potential to enable a wirelessly controlled stimulation at a single-neuron level without requiring genetic modification of the neural tissue and no toxicity has yet been reported. Their potential as a new tool for targeting the brain is discussed. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Cardiovascular Disease Therapeutic Approaches and Drug Discovery > Neurological Disease.

Europium-Doped Cerium Oxide Nanoparticles for Microglial Amyloid Beta Clearance and Homeostasis

Alzheimer's disease (AD) is the most common neurodegenerative disorder. Pathologically, the disease is characterized by the deposition of amyloid beta (Aβ) plaques and the presence of neurofibrillary tangles. These drive microglia neuroinflammation and consequent neurodegeneration. While the means to affect Aβ plaque accumulation pharmacologically was achieved, how it affects disease outcomes remains uncertain. Cerium oxide (CeO₂) reduces Aβ plaques, oxidative stress, inflammation, and AD signs and symptoms. In particular, CeO₂ nanoparticles (CeO₂NPs) induce free-radical-scavenging and cell protective intracellular signaling. This can ameliorate the pathobiology of an AD-affected brain. To investigate whether CeO₂NPs affect microglia neurotoxic responses, a novel formulation of europium-doped CeO₂NPs (EuCeO₂NPs) was synthesized. We then tested EuCeO₂NPs for its ability to generate cellular immune homeostasis in AD models. EuCeO₂NPs attenuated microglia BV2 inflammatory activities after Aβ_1-42 exposure by increasing the cells' phagocytic and Aβ degradation activities. These were associated with increases in the expression of the CD36 scavenger receptor. EuCeO₂NPs facilitated Aβ endolysosomal trafficking and abrogated microglial inflammatory responses. We posit that EuCeO₂NPs may be developed as an AD immunomodulator.

Lipid-Based Nanocarriers for Neurological Disorders: A Review of the State-of-the-Art and Therapeutic Success to Date

Neurodegenerative disorders including Alzheimer's, Parkinson's, and dementia are chronic and advanced diseases that are associated with loss of neurons and other related pathologies. Furthermore, these disorders involve structural and functional defections of the blood-brain barrier (BBB). Consequently, advances in medicines and therapeutics have led to a better appreciation of various pathways associated with the development of neurodegenerative disorders, thus focusing on drug discovery and research for targeted drug therapy to the central nervous system (CNS). Although the BBB functions as a shield to prevent toxins in the blood from reaching the brain, drug delivery to the CNS is hindered by its presence. Owing to this, various formulation approaches, including the use of lipid-based nanocarriers, have been proposed to address shortcomings related to BBB permeation in CNS-targeted therapy, thus showing the potential of these carriers for translation into clinical use. Nevertheless, to date, none of these nanocarriers has been granted market authorization following the successful completion of all stages of clinical trials. While the aforementioned benefits of using lipid-based carriers underscores the need to fast-track their translational development into clinical practice, technological advances need to be initiated to achieve appropriate capacity for scale-up and the production of affordable dosage forms.

Carbodiimide-Driven Dimerization and Self-Assembly of Artificial, Ribose-Based Amphiphiles

The aqueous self‐assembly of amphiphiles into aggregates such as micelles and vesicles has been widely investigated over the past decades with applications ranging from materials science to drug delivery. The combination of characteristic properties of nucleic acids and amphiphiles is of substantial interest to mimic biological self‐organization and compartmentalization. Herein, we present ribose‐ and ribonucleotide‐based amphiphiles and investigate their self‐assembly as well as their fundamental reactivity. We found that various types of aggregates are formed, ranging in size from nanometers to micrometers and all amphiphiles exhibit aggregation‐induced emission (AIE) in solution as well as in the solid state. We also observed that the addition of 1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide (EDC) leads to rapid and selective dimerization of the amphiphiles into pyrophosphates, which decreases the critical aggregation concentration (CAC) by a factor of 25 when compared to the monomers. Since the propensity for amphiphile dimerization is correlated with their tendency to self‐assemble, our results may be relevant for the formation of rudimentary compartments under prebiotic conditions.

Cysteine Donor-Based Brain-Targeting Prodrug: Opportunities and Challenges

Overcoming blood-brain barrier (BBB) to improve brain bioavailability of therapeutic drug remains an ongoing concern. Prodrug is one of the most reliable approaches for delivering agents with low-level BBB permeability into the brain. The well-known antioxidant capacities of cysteine (Cys) and its vital role in glutathione (GSH) synthesis indicate that Cys-based prodrug could potentiate therapeutic drugs against oxidative stress-related neurodegenerative disorders. Moreover, prodrug with Cys moiety could be recognized by the excitatory amino acid transporter 3 (EAAT3) that is highly expressed at the BBB and transports drug into the brain. In this review, we summarized the strategies of crossing BBB, properties of EAAT3 and its natural substrates, Cys and its donors, and Cys donor-based brain-targeting prodrugs by referring to recent investigations. Moreover, the challenges that we are faced with and future research orientations were also addressed and proposed. It is hoped that present review will provide evidence for the pursuit of novel Cys donor-based brain-targeting prodrug.

Recent advancements in nanoparticle-mediated approaches for restoration of multiple sclerosis

Multiple Sclerosis (MS) is an autoimmune disease with complicated immunopathology which necessitates considering multifactorial aspects for its management. Nano-sized pharmaceutical carriers named nanoparticles (NPs) can support impressive management of disease not only in early detection and prognosis level but also in a therapeutic manner. The most prominent initiator of MS is the domination of cellular immunity to humoral immunity and increment of inflammatory cytokines. The administration of several platforms of NPs for MS management holds great promise so far. The efforts for MS management through in vitro and in vivo (experimental animal models) evaluations, pave a new way to a highly efficient therapeutic means and aiding its translation to the clinic in the near future.

Smart Nanomedicine to Enable Crossing Blood-Brain Barrier Delivery of Checkpoint Blockade Antibody for Immunotherapy of Glioma

Immune checkpoint blockade (ICB) therapy has shown tremendous promises in the treatment of various types of tumors. However, ICB therapy with antibodies appears to be less effective for glioma, partly owing to the existence of the blood-brain barrier (BBB) that impedes the entrance of therapeutics including most proteins to the central nervous system (CNS). Herein, considering the widely existing nicotinic acetylcholine receptors (nAChRs) and choline transporters (ChTs) on the surface of BBB, a choline analogue 2-methacryloyloxyethyl phosphorylcholine (MPC) is employed to fabricate the BBB-crossing copolymer via free-radical polymerization, followed by conjugation with antiprogrammed death-ligand 1 (anti-PD-L1) via a pH-sensitive traceless linker. The obtained nanoparticles exhibit significantly improved BBB-crossing capability owing to the receptor-mediated transportation after intravenous injection in an orthotopic glioma tumor model. Within the acidic glioma microenvironment, anti-PD-L1 would be released from such pH-responsive nanoparticles, further triggering highly effective ICB therapy of glioma to significantly prolong animal survival. This work thus realizes glioma microenvironment responsive BBB-crossing delivery of ICB antibodies, promising for the next generation immunotherapy of glioma.

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.

Characterization, Cytotoxicity and Anti-Inflammatory Effect Evaluation of Nanocapsules Containing Nicotine

(1) Background: Nanotechnology is an emerging field that can be applied in the biomedical area. In this study, Eudragit nanocapsules (NCs) containing nicotine were produced. Nicotine is the main alkaloid found in tobacco and has anti-inflammatory properties. NCs containing nicotine may be used as an adjuvant therapy in the treatment of inflammation in the central nervous system. (2) Methods: Nanocapsules were prepared by the interfacial deposition of the pre-formed polymer method and characterized in terms of zeta potential, diameter, polydispersity index, pH, encapsulation efficiency (EE), stability and sustained release profile. In vitro tests with the PC12 cell line were performed, such as MTT, LIVE/DEAD and ELISA assays, to verify their cytotoxic and anti-inflammatory effects. (3) Results: The nanocapsules presented satisfactory values of the characterization parameters; however, poor encapsulation was obtained for nicotine (8.17% ± 0.47). The in vitro tests showed that the treatment with nanocapsules reduced cell viability, which suggests that the Eudragit or the amount of polymer on top of the cells may be detrimental to them, as the cells were able to survive when treated with bulk nicotine. ELISA showed an increment in the expression of IL-6 and IL-1β, corroborating the hypothesis that NCs were toxic to the cells because of the increase in the levels of these pro-inflammatory cytokines. (4) Conclusions: This study demonstrates that NCs of Eudragit present toxicity. It is therefore necessary to improve NC formulation to obtain better values for the encapsulation efficiency and reduce toxicity of these nanodevices.

Development of Novel Therapeutics Targeting the Blood-Brain Barrier: From Barrier to Carrier

The blood-brain barrier (BBB) is a highly specialized neurovascular unit, initially described as an intact barrier to prevent toxins, pathogens, and potentially harmful substances from entering the brain. An intact BBB is also critical for the maintenance of normal neuronal function. In cerebral vascular diseases and neurological disorders, the BBB can be disrupted, contributing to disease progression. While restoration of BBB integrity serves as a robust biomarker of better clinical outcomes, the restrictive nature of the intact BBB presents a major hurdle for delivery of therapeutics into the brain. Recent studies show that the BBB is actively engaged in crosstalk between neuronal and the circulatory systems, which defines another important role of the BBB: as an interfacing conduit that mediates communication between two sides of the BBB. This role has been subject to extensive investigation for brain-targeted drug delivery and shows promising results. The dual roles of the BBB make it a unique target for drug development. Here, recent developments and novel strategies to target the BBB for therapeutic purposes are reviewed, from both barrier and carrier perspectives.

Emerging Applications of Nanotechnology in Healthcare Systems: Grand Challenges and Perspectives

Healthcare, as a basic human right, has often become the focus of the development of innovative technologies. Technological progress has significantly contributed to the provision of high-quality, on-time, acceptable, and affordable healthcare. Advancements in nanoscience have led to the emergence of a new generation of nanostructures. Each of them has a unique set of properties that account for their astonishing applications. Since its inception, nanotechnology has continuously affected healthcare and has exerted a tremendous influence on its transformation, contributing to better outcomes. In the last two decades, the world has seen nanotechnology taking steps towards its omnipresence and the process has been accelerated by extensive research in various healthcare sectors. The inclusion of nanotechnology and its allied nanocarriers/nanosystems in medicine is known as nanomedicine, a field that has brought about numerous benefits in disease prevention, diagnosis, and treatment. Various nanosystems have been found to be better candidates for theranostic purposes, in contrast to conventional ones. This review paper will shed light on medically significant nanosystems, as well as their applications and limitations in areas such as gene therapy, targeted drug delivery, and in the treatment of cancer and various genetic diseases. Although nanotechnology holds immense potential, it is yet to be exploited. More efforts need to be directed to overcome these limitations and make full use of its potential in order to revolutionize the healthcare sector in near future.

Nerve Growth Factor Biodelivery: A Limiting Step in Moving Toward Extensive Clinical Application?

Nerve growth factor (NGF) was the first-discovered member of the neurotrophin family, a class of bioactive molecules which exerts powerful biological effects on the CNS and other peripheral tissues, not only during development, but also during adulthood. While these molecules have long been regarded as potential drugs to combat acute and chronic neurodegenerative processes, as evidenced by the extensive data on their neuroprotective properties, their clinical application has been hindered by their unexpected side effects, as well as by difficulties in defining appropriate dosing and administration strategies. This paper reviews aspects related to the endogenous production of NGF in healthy and pathological conditions, along with conventional and biomaterial-assisted delivery strategies, in an attempt to clarify the impediments to the clinical application of this powerful molecule.

Ultrasound-activated nano-TiO2 loaded with temozolomide paves the way for resection of chemoresistant glioblastoma multiforme

Background

Glioblastoma multiforme (GBM) is one of the most daunting issues to modern therapeutics, with a higher mortality rate post-diagnosis. Temozolomide (TMZ) is the only available treatment; however, the frequent resistance leaves the oncologists at a dead end. Therefore, new approaches to circumvent the GBM are highly desired. We have employed TiO2 nanosticks loaded with TMZ as nanomedicine for TMZ-resistant GBM resection in this contribution.

Results

The ultrasonication triple-action effect could greatly facilitate tumor ablation by enhancing the TiO2 nanosticks traversing across BBB, releasing the TMZ payload from TiO2 nanosticks and reactive oxygen species (ROS) generation from TiO2 nanosticks within the GBM milieu. The tumor ablation was confirmed by MTT and Annexin(v)-PI assays, apoptotic proteins expression via western blot and ROS level detection in vitro, whereas tumor volume, weight, survival rate, and relative photon flux in the xenograft and orthoptic TMZ-resistant GBM murine models as in vivo.

Conclusion

We found this nanomedicine-based ultrasound modality highly efficient in GBM treatment and is of future clinical application value due to the employment of already FDA-approved techniques and nanomedicine.

The Prospect of Nanoparticle Systems for Modulating Immune Cell Polarization During Central Nervous System Infection

The blood-brain barrier (BBB) selectively restricts the entry of molecules from peripheral circulation into the central nervous system (CNS) parenchyma. Despite this protective barrier, bacteria and other pathogens can still invade the CNS, often as a consequence of immune deficiencies or complications following neurosurgical procedures. These infections are difficult to treat since many bacteria, such as Staphylococcus aureus, encode a repertoire of virulence factors, can acquire antibiotic resistance, and form biofilm. Additionally, pathogens can leverage virulence factor production to polarize host immune cells towards an anti-inflammatory phenotype, leading to chronic infection. The difficulty of pathogen clearance is magnified by the fact that antibiotics and other treatments cannot easily penetrate the BBB, which requires extended regimens to achieve therapeutic concentrations. Nanoparticle systems are rapidly emerging as a promising platform to treat a range of CNS disorders. Nanoparticles have several advantages, as they can be engineered to cross the BBB with specific functionality to increase cellular and molecular targeting, have controlled release of therapeutic agents, and superior bioavailability and circulation compared to traditional therapies. Within the CNS environment, therapeutic actions are not limited to directly targeting the pathogen, but can also be tailored to modulate immune cell activation to promote infection resolution. This perspective highlights the factors leading to infection persistence in the CNS and discusses how novel nanoparticle therapies can be engineered to provide enhanced treatment, specifically through modulation of immune cell polarization.

The Mechanism of Asparagine Endopeptidase in the Progression of Malignant Tumors: A Review

Asparagine endopeptidase (AEP), also called legumain, is currently the only known cysteine protease that specifically cleaves peptide bonds in asparaginyl residue in the mammalian genome. Since 2003, AEP has been reported to be widely expressed in a variety of carcinomas and is considered a potential therapeutic target. In the following years, researchers intensively investigated the substrates of AEP and the mechanism of AEP in partial tumors. With the identification of substrate proteins such as P53, integrin αvβ3, MMP-2, and MMP-9, the biochemical mechanism of AEP in carcinomas is also more precise. This review will clarify the probable mechanisms of AEP in the progression of breast carcinoma, glioblastoma, gastric carcinoma, and epithelial ovarian carcinoma. This review will also discuss the feasibility of targeted therapy with AEP inhibitor (AEPI) in these carcinomas.

The application of multifunctional nanomaterials in Alzheimer's disease: A potential theranostics strategy

By virtue of their small size, nanomaterials can cross the blood-brain barrier and, when modified to target specific cells or regions, can achieve high bioavailability at the intended site of action. Modified nanomaterials are therefore promising agents for the diagnosis and treatment of neurodegenerative diseases such as Alzheimer's disease (AD). Here we review the roles and mechanisms of action of nanomaterials in AD. First, we discuss the general characteristics of nanomaterials and their application to nanomedicine. Then, we summarize recent studies on the diagnosis and treatment of AD using modified nanomaterials. These studies indicate that using nanomaterials is a potential strategy for AD treatment by slowing the progression of AD through enhanced therapeutic effects.

Toxicity evaluation of cadmium-containing quantum dots: A review of optimizing physicochemical properties to diminish toxicity

Fluorescent quantum dots (QDs) have received extensive attention because of their excellent optical properties and wide utilization in biological and biomedical areas. Nonetheless, there have been intense concerns on the cytotoxicity assessment of cadmium-containing QDs due to free cadmium ions release and nano-size effects. This paper reviews the representative synthetic strategies for preparation of cadmium-containing QDs and their applications. Then the toxicity assessments of QDs from cell studies to animal models are discussed, which can aid in improving our understanding of the cytotoxicity of QDs, and the toxicity mechanism is proposed. Several critical physicochemical properties of QDs are discussed and suggestions are provided for optimizing QDs design in view of minimal cytotoxicity. Finally, accurate detection techniques and systematic methodologies for the toxicity assessment of QDs are expected to achieve further breakthroughs in the future, especially in-situ, real-time, and rapid quantitative analysis methods.

Hybrid Graphene-Gold Nanoparticle-based Nucleic Acid Conjugates for Cancer-Specific Multimodal Imaging and Combined Therapeutics

Nanoparticle-based nucleic acid conjugates (NP-NACs) hold great promise for theragnostic (diagnostic and therapeutic) applications. However, several limitations have hindered the realization of their full potential in the clinical treatment of cancer and other diseases. In diagnosis, NP-NACs, combined with conventional optical sensing systems, have been applied for cancer detection in vitro, but low signal-to-noise ratios limit their broad in vivo applications. Meanwhile, the efficiency of NP-NAC-mediated cancer therapies has been limited through the adaptation of alternative pro-survival pathways in cancer cells. The recent emergence of personalized and precision medicine has outlined the importance of both accurate diagnosis and efficient therapeutics in a single platform. As such, we report the controlled assembly of hybrid graphene oxide/gold nanoparticle-based cancer-specific NACs (Au@GO NP-NACs) for multimodal imaging and combined therapeutics. Our developed Au@GO NP-NACs shows excellent surface-enhanced Raman scattering (SERS)-mediated live-cell cancer detection and multimodal synergistic cancer therapy through the use of photothermal, genetic, and chemotherapeutic strategies. Synergistic and selective killing of cancer cells were then demonstrated by using in vitro microfluidic models and nine different cancer cell lines by further incorporating near-infrared photothermal hyperthermia, a Topoisomerase II anti-cancer drug, and cancer targeting peptides. Moreover, with distinctive advantages of the Au@GO NP-NACs for cancer theragnostics, we further demonstrated precision cancer treatment through the detection of cancer cells in vivo using SERS followed by efficient ablation of the tumor. Therefore, our Au@GO NP-NACs could pave a new road for the advanced theragnostics of cancer as well as many other diseases.

Advances in nanomedicines for diagnosis of central nervous system disorders

In spite of a great improvement in medical health services and an increase in lifespan, we have witnessed a skyrocket increase in the incidence of central nervous system (CNS) disorders including brain tumors, neurodegenerative diseases (Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease), ischemic stroke, and epilepsy, which have seriously undermined the quality of life and substantially increased economic and societal burdens. Development of diagnostic methods for CNS disorders is still in the early stage, and the clinical outcomes suggest these methods are not ready for the challenges associated with diagnosis of CNS disorders, such as early detection, specific binding, sharp contrast, and continuous monitoring of therapeutic interventions. Another challenge is to overcome various barrier structures during delivery of diagnostic agents, especially the blood-brain barrier (BBB). Fortunately, utilization of nanomaterials has been pursued as a potential and promising strategy to address these challenges. This review will discuss anatomical and functional structures of BBB and transport mechanisms of nanomaterials across the BBB, and special emphases will be placed on the state-of-the-art advances in the development of nanomedicines from a variety of nanomaterials for diagnosis of CNS disorders. Meanwhile, current challenges and future perspectives in this field are also highlighted.

Effective Modulation of CNS Inhibitory Microenvironment using Bioinspired Hybrid-Nanoscaffold-Based Therapeutic Interventions

Central nervous system (CNS) injuries are often debilitating, and most currently have no cure. This is due to the formation of a neuroinhibitory microenvironment at injury sites, which includes neuroinflammatory signaling and non-permissive extracellular matrix (ECM) components. To address this challenge, a viscous interfacial self-assembly approach, to generate a bioinspired hybrid 3D porous nanoscaffold platform for delivering anti-inflammatory molecules and establish a favorable 3D-ECM environment for the effective suppression of the neuroinhibitory microenvironment, is developed. By tailoring the structural and biochemical properties of the 3D porous nanoscaffold, enhanced axonal growth from the dual-targeting therapeutic strategy in a human induced pluripotent stem cell (hiPSC)-based in vitro model of neuroinflammation is demonstrated. Moreover, nanoscaffold-based approaches promote significant axonal growth and functional recovery in vivo in a spinal cord injury model through a unique mechanism of anti-inflammation-based fibrotic scar reduction. Given the critical role of neuroinflammation and ECM microenvironments in neuroinhibitory signaling, the developed nanobiomaterial-based therapeutic intervention may pave a new road for treating CNS injuries.

Nanostructured Lipid Carriers Made of Ω-3 Polyunsaturated Fatty Acids: In Vitro Evaluation of Emerging Nanocarriers to Treat Neurodegenerative Diseases

Neurodegenerative diseases (ND) are one of the main problems of public health systems in the 21st century. The rise of nanotechnology-based drug delivery systems (DDS) has become in an emerging approach to target and treat these disorders related to the central nervous system (CNS). Among others, the use of nanostructured lipid carriers (NLCs) has increased in the last few years. Up to today, most of the developed NLCs have been made of a mixture of solid and liquid lipids without any active role in preventing or treating diseases. In this study, we successfully developed NLCs made of a functional lipid, such as the hydroxylated derivate of docohexaenoic acid (DHAH), named DHAH-NLCs. The newly developed nanocarriers were around 100 nm in size, with a polydispersity index (PDI) value of <0.3, and they exhibited positive zeta potential due to the successful chitosan (CS) and TAT coating. DHAH-NLCs were shown to be safe in both dopaminergic and microglia primary cell cultures. Moreover, they exhibited neuroprotective effects in dopaminergic neuron cell cultures after exposition to 6-hydroxydopamine hydrochloride (6-OHDA) neurotoxin and decreased the proinflammatory cytokine levels in microglia primary cell cultures after lipopolysaccharide (LPS) stimuli. The levels of the three tested cytokines, IL-6, IL-1β and TNF-α were decreased almost to control levels after the treatment with DHAH-NLCs. Taken together, these data suggest the suitability of DHAH-NLCs to attaining enhanced and synergistic effects for the treatment of NDs.

Blood-brain barrier amenable gold nanoparticles biofabrication in aged cell culture medium

Green fabrication of nanoscale materials is highly desirable because of associated adverse effects with conventional nanomaterial biomedical applications. Moreover, the higher selective nature of the blood-brain barrier (BBB) limits the brain ailments treatment through conventional chemotherapy, thus providing room for nanotechnology-based modalities for BBB traversing. In this contribution, we have biosynthesized gold nanoparticles from the HAuCl4 solution in the aged cells culture medium. This approach is highly facile without any other chemical utilization. The cell culture medium age and cell number can tune the Au nanoparticles (AuNPs) size from 2 to several hundred nm. The 24 h MTT assay and cell uptake studies in vitro and murine models' vital organs (liver, kidney, spleen, lung, and heart) study up to 48 h demonstrated that biosynthesized AuNPs were biocompatible and BBB amenable. Interestingly, the transferrin and cell culture medium isolated proteins were found factors responsible for HAuCl4 solution biomineralization and size control. Moreover, the protein corona on biosynthesized AuNPs could help them traverse BBB both in vitro and in vivo, suggesting their potential applications for brain disease theranostics. In conclusion, the biosynthesis of AuNPs from aged cells medium is highly facile, green, and biocompatible for brain disease theranostics.

Nanoemulsions for targeting the neurodegenerative diseases: Alzheimer's, Parkinson's and Prion's

Neurodegenerative diseases need the drugs to be delivered right inside the brain to maximizing the therapeutic effects. This can be achieved by use of novel targeted delivery systems such as nanoemulsions. Nanoemulsions (NE) are nano-sized emulsions that are manufactured for enhancing the delivery of drugs to the targeted site and minimize adverse effects and toxic reactions. Looking into the advanced pharmaceutical applications of NE, the present review gives an insight to the understanding of the application of NE in NDs like AD, PD and Prion's disease. The review also touches upon the pathophysiology of these ND diseases to have a clear understanding of the molecular aspects of the disease. Finally, the review sets a standpoint of nanoemulsion's significance in the treatment therapy of ND besides the drawbacks associated with the current drug therapy in NDs.

Current insights on lipid nanocarrier-assisted drug delivery in the treatment of neurodegenerative diseases

The central nervous system (CNS) is vulnerable to pathologic processes that lead to the development of neurodegenerative disorders like Alzheimer's, Parkinson's and Huntington's diseases, Multiple sclerosis or Amyotrophic lateral sclerosis. These are chronic and progressive pathologies characterized by the loss of neurons and the formation of misfolded proteins. Additionally, neurodegenerative diseases are accompanied by a structural and functional dysfunction of the blood-brain barrier (BBB). Although serving as a protection for the CNS, the existence of physiological barriers, especially the BBB, limits the access of several therapeutic agents to the brain, constituting a major hindrance in neurotherapeutics advancement. In this regard, nanotechnology-based approaches have arisen as a promising strategy to not only improve drug targeting to the brain, but also to increase bioavailability. Lipid nanocarriers such as liposomes, solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC), microemulsions and nanoemulsions, have already proven their potential for enhancing brain transport, crossing more easily into the CNS and allowing the administration of medicines that could benefit the treatment of neurological pathologies. Given the socioeconomic impact of such conditions and the advent of nanotechnology that inevitably leads to more effective and superior therapeutics for their management, it is imperative to constantly update on the current knowledge of these topics. Herein, we provide insight on the BBB and the pathophysiology of the main neurodegenerative disorders. Moreover, this review seeks to highlight the several approaches that can be used to improve the delivery of therapeutic agents to the CNS, while also offering an extensive overview of the latest efforts regarding the use of lipid-based nanocarriers in the management of neurodegenerative diseases.

Development of a hybrid nanocarrier-recognizing tumor vasculature and penetrating the BBB for glioblastoma multi-targeting therapy

The success of glioma chemotherapy is hampered by poor drug penetration ability across the blood-brain barrier (BBB) and low intratumoral drug concentration. Novel tumor-targeted delivery systems are useful in specifically accumulating in the tumor foci and penetrating into the glioma core after entering into the brain. Here we show that a multi-targeting hybrid nanocarrier (Pep-MLHA HNPs) system based on hyaluronic acid (HA)-modified polymer and a functional peptide possesses multi-target capability and stronger penetration ability into the core of three-dimensional tumor spheroids, could migrate efficiently across the BBB in vitro. The intensity of the Pep-MLHA HNPs after transporting across the BBB was 5.2-fold and 5.6-fold higher than that of ML NPs in C6 and U87 cells, respectively. More interestingly, this multi-targeting hybrid system displayed high colloidal stability in PBS solution, and weak negative zeta potential (-1.99 ± 0.655 mV) minimizing nonspecific interactions with plasma proteins and promoting long-term circulation in vivo. Additionally, the multi-targeting hybrid system induced enhanced tumor localization in U87 in situ-bearing nude mice and xenograft-bearing nude mice after systemic administration. Furthermore, docetaxel (DTX)-loaded Pep-MLHA HNPs showed negligible systemic toxicity and enhanced therapeutic efficacy, with significantly improved survival rates in intracranial C6 glioma-bearing rats. The 50% survival rate of DTX/Pep-MLHA HNPs-treated rats (40 days) was significantly longer than that of rats treated with NS (22 days), Taxotere® (25 days), DTX/ML NPs (25 days), DTX/Pep NPs (32 days) and DTX/MLHA NPs (29 days). All the results suggested that the multi-targeting hybrid nanocarrier system is promising for glioma treatment.

Effects of gold nanostructures on differentiation of mesenchymal stem cells

Nanoparticles are nanocrystals with complex facets and defective structures that do not adopt an idealised shape. Various physicochemical parameters of nanoparticles, such as surface composition, size, and stiffness, can regulate differentiation in mesenchymal stem cells (MSCs), but the influence of shapes with many edges and corner regions has not been investigated. Herein, we investigated the effects of two gold nanostructures modified with 11-mercaptoundecanoic acid, namely gold nanocubes (MUA-AuNCs) and nanooctahedras (MUA-AuNOs), on viability and differentiation in rat bone marrow MSCs (bMSCs). Analysis of cytotoxicity and proliferation demonstrated good biocompatibility, with concentrations <100 μg·mL^-1 not significantly different from untreated controls. Alkaline phosphatase activity and Alizarin Red S staining revealed weaker potential for bMSCs to differentiate into osteoblasts following treatment with both low (5 μg·mL^-1) and high (25 μg·mL^-1) concentrations of the gold nanostructures. By contrast, Oil Red O staining showed that both nanostructures enhanced adipogenic differentiation, and upregulated peroxisome proliferator-activated receptor gamma (PPARγ) and fatty acid binding protein-4 (Fabp4) expression at both mRNA and protein levels. The effects on differentiation were both structure- and dose-dependent; MUA-AuNOs were more effective for enhancing adipogenic differentiation and weakening osteogenic differentiation, possibly due to generating higher levels of reactive oxygen species (ROS). These findings lay the foundation for using these nanoparticles as ex vivo labels in MSC-based imaging and therapy.

Dendrimer-Based Drug Delivery Systems for Brain Targeting

Human neuroscience has made remarkable progress in understanding basic aspects of functional organization; it is a renowned fact that the blood-brain barrier (BBB) impedes the permeation and access of most drugs to central nervous system (CNS) and that many neurological diseases remain undertreated. Therefore, a number of nanocarriers have been designed over the past few decades to deliver drugs to the brain. Among these nanomaterials, dendrimers have procured an enormous attention from scholars because of their nanoscale uniform size, ease of multi-functionalization, and available internal cavities. As hyper-branched 3D macromolecules, dendrimers can be maneuvered to transport diverse therapeutic agents, incorporating small molecules, peptides, and genes; diminishing their cytotoxicity; and improving their efficacy. Herein, the present review will give exhaustive details of extensive researches in the field of dendrimer-based vehicles to deliver drugs through the BBB in a secure and effectual manner. It is also a souvenir in commemorating Donald A. Tomalia on his 80th birthday.