The effect of lipid nanoparticle PEGylation on neuroinflammatory response in mouse brain

Advancing the Frontiers of Neuroelectrodes: A Paradigm Shift towards Enhanced Biocompatibility and Electrochemical Performance

The aim of this study is the fabrication of unprecedented neuroelectrodes, replete with exceptional biological and electrical attributes. Commencing with the synthesis of polyethylene glycol and polyethyleneimine-modified iron oxide nanoparticles, the grafting of Dimyristoyl phosphatidylcholine was embarked upon to generate DMPC-SPION nanoparticles. Subsequently, the deposition of DMPC-SPIONs onto a nickel-chromium alloy electrode facilitated the inception of an innovative neuroelectrode-DMPC-SPION. A meticulous characterization of DMPC-SPIONs ensued, encompassing zeta potential, infrared spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction analyses. Evaluations pertaining to hemolysis and cytotoxicity were conducted to ascertain the biocompatibility and biosafety of DMPC-SPIONs. Ultimately, a comprehensive assessment of the biocompatibility, electrochemical properties, and electrophysiological signal acquisition capabilities of DMPC-SPION neuroelectrodes was undertaken. These findings conclusively affirm the exemplary biocompatibility, electrochemical capabilities, and outstanding capability in recording electrical signals of DMPC-SPION neuroelectrodes, with an astounding 91.4% augmentation in electrode charge and a noteworthy 13% decline in impedance, with peak potentials reaching as high as 171 μV and an impressive signal-to-noise ratio of 15.92. Intriguingly, the novel DMPC-SPION neuroelectrodes herald an innovative pathway towards injury repair as well as the diagnosis and treatment of neurological disorders.

Blood-Brain Barrier-Targeting Nanoparticles: Biomaterial Properties and Biomedical Applications in Translational Neuroscience

Overcoming the blood-brain barrier (BBB) remains a significant hurdle in effective drug delivery to the brain. While the BBB serves as a crucial protective barrier, it poses challenges in delivering therapeutic agents to their intended targets within the brain parenchyma. To enhance drug delivery for the treatment of neurological diseases, several delivery technologies to circumvent the BBB have been developed in the last few years. Among them, nanoparticles (NPs) are one of the most versatile and promising tools. Here, we summarize the characteristics of NPs that facilitate BBB penetration, including their size, shape, chemical composition, surface charge, and importantly, their conjugation with various biological or synthetic molecules such as glucose, transferrin, insulin, polyethylene glycol, peptides, and aptamers. Additionally, we discuss the coating of NPs with surfactants. A comprehensive overview of the common in vitro and in vivo models of the BBB for NP penetration studies is also provided. The discussion extends to discussing BBB impairment under pathological conditions and leveraging BBB alterations under pathological conditions to enhance drug delivery. Emphasizing the need for future studies to uncover the inherent therapeutic properties of NPs, the review advocates for their role beyond delivery systems and calls for efforts translating NPs to the clinic as therapeutics. Overall, NPs stand out as a highly promising therapeutic strategy for precise BBB targeting and drug delivery in neurological disorders.

Comparative Studies of the Uptake and Internalization Pathways of Different Lipid Nano-Systems Intended for Brain Delivery

Lipid nano-systems were prepared and characterized in a series of well-established in vitro tests that could assess their interactions with the hCMEC/D3 and SH-SY5Y cell lines as a model for the blood-brain barrier and neuronal function, accordingly. The prepared formulations of nanoliposomes and nanostructured lipid carriers were characterized by z-average diameters of ~120 nm and ~105 nm, respectively, following a unimodal particle size distribution (PDI < 0.3) and negative Z-potential (-24.30 mV to -31.20 mV). Stability studies implied that the nano-systems were stable in a physiologically relevant medium as well as human plasma, except nanoliposomes containing poloxamer on their surface, where there was an increase in particle size of ~26%. The presence of stealth polymer tends to decrease the amount of adsorbed proteins onto a particle's surface, according to protein adsorption studies. Both formulations of nanoliposomes were characterized by a low cytotoxicity, while their cell viability was reduced when incubated with the highest concentration (100 μg/mL) of nanostructured lipid formulations, which could have been associated with the consumption of cellular energy, thus resulting in a reduction in metabolic active cells. The uptake of all the nano-systems in the hCMEC/D3 and SH-SY5Y cell lines was successful, most likely following ATP-dependent internalization, as well as transport via passive diffusion.

Recent Progress of Lipid Nanoparticles-Based Lipophilic Drug Delivery: Focus on Surface Modifications

Numerous drugs have emerged to treat various diseases, such as COVID-19, cancer, and protect human health. Approximately 40% of them are lipophilic and are used for treating diseases through various delivery routes, including skin absorption, oral administration, and injection. However, as lipophilic drugs have a low solubility in the human body, drug delivery systems (DDSs) are being actively developed to increase drug bioavailability. Liposomes, micro-sponges, and polymer-based nanoparticles have been proposed as DDS carriers for lipophilic drugs. However, their instability, cytotoxicity, and lack of targeting ability limit their commercialization. Lipid nanoparticles (LNPs) have fewer side effects, excellent biocompatibility, and high physical stability. LNPs are considered efficient vehicles of lipophilic drugs owing to their lipid-based internal structure. In addition, recent LNP studies suggest that the bioavailability of LNP can be increased through surface modifications, such as PEGylation, chitosan, and surfactant protein coating. Thus, their combinations have an abundant utilization potential in the fields of DDSs for carrying lipophilic drugs. In this review, the functions and efficiencies of various types of LNPs and surface modifications developed to optimize lipophilic drug delivery are discussed.

Carbon nanomaterials for drug delivery and tissue engineering

Carbon nanomaterials are some of the state-of-the-art materials used in drug-delivery and tissue-engineering research. Compared with traditional materials, carbon nanomaterials have the advantages of large specific surface areas and unique properties and are more suitable for use in drug delivery and tissue engineering after modification. Their characteristics, such as high drug loading and tissue loading, good biocompatibility, good targeting and long duration of action, indicate their great development potential for biomedical applications. In this paper, the synthesis and application of carbon dots (CDs), carbon nanotubes (CNTs) and graphene in drug delivery and tissue engineering are reviewed in detail. In this review, we discuss the current research focus and existing problems of carbon nanomaterials in order to provide a reference for the safe and effective application of carbon nanomaterials in drug delivery and tissue engineering.

Crossing the Blood-Brain Barrier: Advances in Nanoparticle Technology for Drug Delivery in Neuro-Oncology

The blood-brain barrier (BBB) constitutes a microvascular network responsible for excluding most drugs from the brain. Treatment of brain tumors is limited by the impermeability of the BBB and, consequently, survival outcomes for malignant brain tumors remain poor. Nanoparticles (NPs) represent a potential solution to improve drug transport to brain tumors, given their small size and capacity to target tumor cells. Here, we review the unique physical and chemical properties of NPs that aid in BBB transport and discuss mechanisms of NP transport across the BBB, including paracellular transport, carrier-mediated transport, and adsorptive- and receptor-mediated transcytosis. The major types of NPs investigated for treatment of brain tumors are detailed, including polymeric NPs, liposomes, solid lipid NPs, dendrimers, metals, quantum dots, and nanogels. In addition to their role in drug delivery, NPs can be used as imaging contrast agents and can be conjugated with imaging probes to assist in visualizing tumors, demarcating lesion boundaries and margins, and monitoring drug delivery and treatment response. Multifunctional NPs can be designed that are capable of targeting tumors for both imaging and therapeutic purposes. Finally, limitations of NPs for brain tumor treatment are discussed.

Nanoparticles for Diagnosis and Target Therapy in Pediatric Brain Cancers

Pediatric brain tumors represent the most common types of childhood cancer and novel diagnostic and therapeutic solutions are urgently needed. The gold standard treatment option for brain cancers in children, as in adults, is tumor resection followed by radio- and chemotherapy, but with discouraging therapeutic results. In particular, the last two treatments are often associated to significant neurotoxicity in the developing brain of a child, with resulting disabilities such as cognitive problems, neuroendocrine, and neurosensory dysfunctions/deficits. Nanoparticles have been increasingly and thoroughly investigated as they show great promises as diagnostic tools and vectors for gene/drug therapy for pediatric brain cancer due to their ability to cross the blood–brain barrier. In this review we will discuss the developments of nanoparticle-based strategies as novel precision nanomedicine tools for diagnosis and therapy in pediatric brain cancers, with a particular focus on targeting strategies to overcome the main physiological obstacles that are represented by blood–brain barrier.

Involvement of Microglia in Neurodegenerative Diseases: Beneficial Effects of Docosahexahenoic Acid (DHA) Supplied by Food or Combined with Nanoparticles

Neurodegenerative diseases represent a major public health issue and require better therapeutic management. The treatments developed mainly target neuronal activity. However, an inflammatory component must be considered, and microglia may constitute an important therapeutic target. Given the difficulty in developing molecules that can cross the blood–brain barrier, the use of food-derived molecules may be an interesting therapeutic avenue. Docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid (22:6 omega-3), has an inhibitory action on cell death and oxidative stress induced in the microglia. It also acts on the inflammatory activity of microglia. These data obtained in vitro or on animal models are corroborated by clinical trials showing a protective effect of DHA. Whereas DHA crosses the blood–brain barrier, nutritional intake lacks specificity at both the tissue and cellular level. Nanomedicine offers new tools which favor the delivery of DHA at the cerebral level, especially in microglial cells. Because of the biological activities of DHA and the associated nanotargeting techniques, DHA represents a therapeutic molecule of interest for the treatment of neurodegenerative diseases.

Safety considerations for nanoparticle gene delivery in pediatric brain tumors

Current standard of care for many CNS tumors involves surgical resection followed by chemotherapy and/or radiation. Some pediatric brain tumor types are infiltrative and diffuse in nature, which reduces the role for surgery. Furthermore, children are extremely vulnerable to neurological sequelae from surgery and radiation therapy, thus alternative approaches are in critical need. As molecular targets underlying various cancers become more clearly defined, there is an increasing push for targeted gene therapies. Viral vectors and nonviral nanoparticles have been thoroughly investigated for gene delivery and show promise as vectors for gene therapy for pediatric brain cancer. Here, we review inorganic and organic materials in development for nanoparticle gene delivery to the brain with a particular focus on safety.

Improved Physicochemical Properties of Curcumin-Loaded Solid Lipid Nanoparticles Stabilized by Sodium Caseinate-Lactose Maillard Conjugate

To improve the water solubility, antioxidant activity, and chemical stability of curcumin, solid lipid nanoparticles (SLNs) were fabricated using equal masses of propylene glycol monopalmitate and glyceryl monostearate as the lipid matrix and sodium caseinate-lactose (NaCas-Lac) Maillard conjugate as the emulsifier. The entrapment efficiency was more than 90% when curcumin was 2.5% and 5.0% of lipid mass, and the SLNs were stable during 30-day storage. SLNs stabilized by NaCas-Lac showed better physicochemical properties than those prepared with NaCas, including higher sphericity and homogeneity; higher entrapment efficiency; better stability against pH, ionic strength, and simulated gastrointestinal digestions; and more controlled release. SLNs also greatly enhanced the antioxidant activity of encapsulated curcumin and the retention of curcumin during storage. Therefore, the present SLNs may find applications to deliver lipophilic compounds in functional foods and beverages.

Nanoparticle-Based Strategies to Treat Neuro-Inflammation

Neuro-inflammation is a pivotal physio-pathological feature of brain disorders, including neurodegenerative diseases. As such, it is a relevant therapeutic target against which drugs have to be proposed. Targeting neuro-inflammation implies crossing the Blood-Brain Barrier (BBB) to reach the Central Nervous System (CNS). Engineered nanoparticles (ENPs) are promising candidates to carry and deliver drugs to the CNS by crossing the BBB. There are several strategies to design ENPs intended for crossing through the BBB. Herein, we first put nanotechnologies back in their historical context and introduce neuro-inflammation and its consequences in terms of public health. In a second part, we explain how ENPs can get access to the brain and review this area by highlighting recent papers in the field. Finally, after pointing out potential guidelines for preclinical studies involving ENPs, we conclude by opening the debate on the questions of nanosafety and toxicity of these ENPs and in particular on ecotoxicity related to regulatory issues and public concerns.

Calpain activation and disturbance of autophagy are induced in cortical neurons in vitro by exposure to HA/β-Ga2O3:Cr3+ nanoparticles

The toxicity of engineered nanoparticles remains a concern. The knowledge of biohazards associated with particular nanoparticles is crucial to make this cutting-edge technology more beneficial and safe. Here, we evaluated the toxicity of Ga₂O₃ nanoparticles (NPs), which are frequently used to enhance the performance of metal catalysts in a variety of catalytic reactions. The potential inflammatory signaling associated with the toxicity of HA/β-Ga₂O₃:Cr³⁺ NPs in primary cortical neurons was examined. We observed a dose-dependent decrease in cell viability and an increase in apoptosis in neurons following various concentrations (0, 1, 5, 25, 50, 100 µg/ml) of HA/β-Ga₂O₃:Cr³⁺ NPs treatment. Consistently, constitutively active forms of calcineurin (48 kDa) were significantly elevated in cultured primary cortical neurons, which was consistent with calpain activation indicated by the breakdown products of spectrin. Moreover, HA/β-Ga₂O₃:Cr³⁺ NPs result in the elevation of LC3-II formation, SQSTM/p62, and Cathepsin B, whereas phosphorylation of CaMKII (Thr286) and Synapsin I (Ser603) were downregulated in the same context. Taken together, these results demonstrate for the first time that calpain activation and a disturbance of autophagy signaling are evoked by exposure to HA/β-Ga₂O₃:Cr³⁺ NPs, which may contribute to neuronal injury in vitro.

Nanobody-Based Delivery Systems for Diagnosis and Targeted Tumor Therapy

The development of innovative targeted therapeutic approaches are expected to surpass the efficacy of current forms of treatments and cause less damage to healthy cells surrounding the tumor site. Since the first development of targeting agents from hybridoma’s, monoclonal antibodies (mAbs) have been employed to inhibit tumor growth and proliferation directly or to deliver effector molecules to tumor cells. However, the full potential of such a delivery strategy is hampered by the size of mAbs, which will obstruct the targeted delivery system to access the tumor tissue. By serendipity, a new kind of functional homodimeric antibody format was discovered in camelidae, known as heavy-chain antibodies (HCAbs). The cloning of the variable domain of HCAbs produces an attractive minimal-sized alternative for mAbs, referred to as VHH or nanobodies (Nbs). Apart from their dimensions in the single digit nanometer range, the unique characteristics of Nbs combine a high stability and solubility, low immunogenicity and excellent affinity and specificity against all possible targets including tumor markers. This stimulated the development of tumor-targeted therapeutic strategies. Some autonomous Nbs have been shown to act as antagonistic drugs, but more importantly, the targeting capacity of Nbs has been exploited to create drug delivery systems. Obviously, Nb-based targeted cancer therapy is mainly focused toward extracellular tumor markers, since the membrane barrier prevents antibodies to reach the most promising intracellular tumor markers. Potential strategies, such as lentiviral vectors and bacterial type 3 secretion system, are proposed to deliver target-specific Nbs into tumor cells and to block tumor markers intracellularly. Simultaneously, Nbs have also been employed for in vivo molecular imaging to diagnose diseased tissues and to monitor the treatment effects. Here, we review the state of the art and focus on recent developments with Nbs as targeting moieties for drug delivery systems in cancer therapy and cancer imaging.

Preclinical safety of solid lipid nanoparticles and nanostructured lipid carriers: Current evidence from in vitro and in vivo evaluation

Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) were designed as exceptionally safe colloidal carriers for the delivery of poorly soluble drugs. SLN/NLC have the particularity of being composed of excipientsalready approved for use in medicines for human use, which offers a great advantage over any other nanoparticulate system developed from novel materials. Despite this fact, any use of excipients in new route of administration or in new dosage form requires evidence of safety. After 25 years of research on SLN and NLC, enough evidence on their preclinical safety has been published. In the present work, published data on in vitro and in vivo compatibility of SLN/NLC have been surveyed, in order to provide evidence of high biocompatibility distinguished by intended administration route. We also identified critical factors and possible weak points in SLN/NLC formulations, such as the effect of surfactants on the cell viability in vitro, which should be considered for further development.

Cytotoxicity and antibacterial activity of a new generation of nanoparticle-based consolidants for restoration and contribution to the safe-by-design implementation

Works of art are constantly under physical, chemical and biological degradation, so constant restoration is required. Consolidation is an important step in restoration, and traditional approaches and materials have already shown their limitations. To solve these problems, new nanoparticle-based consolidants were developed. No information on their toxicity is yet available. In this work, we focused our attention on potential risks posed by three commercially available nanoparticle-based consolidants: silica (SiO2 NPs), silanized silica (silanized SiO2 NPs) and calcium hydroxide (nanolime) nanoparticle dispersions. Occupational exposure impact was tested on three in vitro models mimicking inhalation, dermal contact and systemic routes. While no toxic effects were observed for nanolime and silanized SiO2 NPs, bare SiO2 NPs showed a dose- and time-dependent damage in all considered models. Corrosion test on EpiSkin® revealed no viability reduction. Works of art degradation is partially due to microorganism activity. Consolidant antibacterial activity was evaluated on three representative bacterial strains. Silica NPs-based consolidants showed effect on specific bacterial groups, while no specificity was observed with nanolime. In conclusion, silanized SiO2 NPs-based consolidant emerged as the safest and bacteriologically active product. The different biological impact of bare and silanized SiO2 NPs highlights the importance of safe-by-design approach in developing nanoparticle-containing products.

Nanomaterial applications in multiple sclerosis inflamed brain

In the last years scientific progress in nanomaterials, where size and shape make the difference, has increased their utilization in medicine with the development of a promising new translational science: nanomedicine. Due to their surface and core biophysical properties, nanomaterials hold the promise for medical applications in central nervous system (CNS) diseases: inflammatory, degenerative and tumors. The present review is focused on nanomaterials at the neuro-immune interface, evaluating two aspects: the possible CNS inflammatory response induced by nanomaterials and the developments of nanomaterials to improve treatment and diagnosis of neuroinflammatory diseases, with a focus on multiple sclerosis (MS). Indeed, nanomedicine allows projecting new ways of drug delivery and novel techniques for CNS imaging. Despite the wide field of application in neurological diseases of nanomaterials, our topic here is to review the more recent development of nanomaterials that cross blood brain barrier (BBB) and reach specific target during CNS inflammatory diseases, a crucial strategy for CNS early diagnosis and drug delivery, indeed the main challenges of nanomedicine.

Novel drug-delivery approaches to the blood-brain barrier

The blood-brain barrier (BBB) maintains homeostasis by blocking toxic molecules from the circulation, but drugs are blocked at the same time. When the dose is increased to enhance the drug concentration in the central nervous system, there are side-effects on peripheral organs. In recent years, genetic therapeutic agents and small molecules have been used in various strategies to penetrate the BBB while minimizing the damage to systemic organs. In this review, we describe several representative methods to circumvent or cross the BBB, including chemical and physical strategies.

When neurons encounter nanoobjects: spotlight on calcium signalling

Nanosized objects are increasingly present in everyday life and in specialized technological applications. In recent years, as a consequence of concern about their potential adverse effects, intense research effort has led to a better understanding of the physicochemical properties that underlie their biocompatibility or potential toxicity, setting the basis for a rational approach to their use in the different fields of application. Among the functional parameters that can be perturbed by interaction between nanoparticles (NPs) and living structures, calcium homeostasis is one of the key players and has been actively investigated. One of the most relevant biological targets is represented by the nervous system (NS), since it has been shown that these objects can access the NS through several pathways; moreover, engineered nanoparticles are increasingly developed to be used for imaging and drug delivery in the NS. In neurons, calcium homeostasis is tightly regulated through a complex set of mechanisms controlling both calcium increases and recovery to the basal levels, and even minor perturbations can have severe consequences on neuronal viability and function, such as excitability and synaptic transmission. In this review, we will focus on the available knowledge about the effects of NPs on the mechanisms controlling calcium signalling and homeostasis in neurons. We have taken into account the data related to environmental NPs, and, in more detail, studies employing engineered NPs, since their more strictly controlled chemical and physical properties allow a better understanding of the relevant parameters that determine the biological responses they elicit. The literature on this specific subject is all quite recent, and we have based the review on the data present in papers dealing strictly with nanoparticles and calcium signals in neuronal cells; while they presently amount to about 20 papers, and no related review is available, the field is rapidly growing and some relevant information is already available. A few general findings can be summarized: most NPs interfere with neuronal calcium homeostasis by interactions at the plasmamembrane, and not following their internalization; influx from the extracellular medium is the main mechanism involved; the effects are dependent in a complex way from concentration, size and surface properties.

Uptake of silica nanoparticles: neurotoxicity and Alzheimer-like pathology in human SK-N-SH and mouse neuro2a neuroblastoma cells

Growing concern has been raised over the potential adverse effects of engineered nanoparticles on human health due to their increasing use in commercial and medical applications. Silica nanoparticles (SiNPs) are one of the most widely used nanoparticles in industry and have been formulated for cellular and non-viral gene delivery in the central nerve system. However, the potential neurotoxicity of SiNPs remains largely unclear. In this study, we investigated the cellular uptake of SiNPs in human SK-N-SH and mouse neuro2a (N2a) neuroblastoma cells treated with 10.0 μg/ml of 15-nm SiNPs for 24 h by transmission electron microscopy. We found that SiNPs were mainly localized in the cytoplasm of the treated cells. The treatment of SiNPs at various concentrations impaired the morphology of SK-N-SH and N2a cells, characterized by increased number of round cells, diminishing of dendrite-like processes and decreased cell density. SiNPs significantly decreased the cell viability, induced cellular apoptosis, and elevated the levels of intracellular reactive oxygen species (ROS) in a dose-dependent manner in both cell lines. Additionally, increased deposit of intracellular β-amyloid 1-42 (Aβ(1-42)) and enhanced phosphorylation of tau at Ser262 and Ser396, two specific pathological hallmarks of Alzheimer's disease (AD), were observed in both cell lines with SiNPs treatment. Concomitantly, the expression of amyloid precursor protein (APP) was up-regulated, while amyloid-β-degrading enzyme neprilysin was down-regulated in SiNP-treated cells. Finally, activity-dependent phosphorylation of glycogen syntheses kinase (GSK)-3β at Ser9 (inactive form) was significantly decreased in SiNP-treated SK-N-SH cells. Taken together, these data demonstrated that exposure to SiNPs induced neurotoxicity and pathological signs of AD. The pre-Alzheimer-like pathology induced by SiNPs might result from the dys-regulated expression of APP/neprilysin and activation of GSK-3β. This is the first study with direct evidence indicating that in addition to neurotoxicity induced by SiNPs, the application of SiNPs might increase the risk of developing AD.

Targeted therapy of brain ischaemia using Fas ligand antibody conjugated PEG-lipid nanoparticles

The translation of experimental stroke research from the laboratory to successful clinical practice remains a formidable challenge. We previously reported that PEGylated-lipid nanoparticles (PLNs) effectively transport across the blood-brain barrier along with less inflammatory responses. In the present study, PLNs conjugated to Fas ligand antibody that selectively present on brain ischaemic region were used for therapeutic targeting. Fluorescent analysis of the mice brain show that encapsulated 3-n-Butylphthalide (dl-NBP) in PLNs conjugated with Fas ligand antibody effectively delivered to ipsilateral region of ischaemic brain. Furthermore, the confocal immunohistochemical study demonstrated that brain-targeted nanocontainers specifically accumulated on OX42 positive microglia cells in ischaemic region of mice model. Finally, dl-NBP encapsulated nano-drug delivery system is resulted in significant improvements in brain injury and in neurological deficit after ischaemia, with the significantly reduced dosages versus regular dl-NBP. Overall, these data suggests that PLNs conjugated to an antibody specific to the Fas ligand constituted an ideal brain targeting drug delivery system for brain ischaemia.