Spatiotemporal tracking of gold nanorods after intranasal administration for brain targeting

Current strategic arsenal and advances in nose to brain nanotheranostics for therapeutic intervention of glioblastoma multiforme

The fight against Glioblastoma multiforme (GBM) is ongoing and the long-term outlook for GBM remains challenging due to low prognosis but every breakthrough brings us closer to improving patient outcomes. Significant hurdles in GBM are heterogeneity, fortified tumor location, and blood-brain barrier (BBB), hindering adequate drug concentrations within functioning brain regions, thus leading to low survival rates. The nasal passageway has become an appealing location to commence the course of cancer therapy. Utilization of the nose-to-brain (N2B) route for drug delivery takes a sidestep from the BBB to allow therapeutics to directly access the central nervous system (CNS) and enhance drug localization in the vicinity of the tumor. This comprehensive review provides insights into pertinent anatomy and cellular organization of the nasal cavity, present-day diagnostic tools, intracranial invasive therapies, and advancements in intranasal (IN) therapies in GBM models for better clinical outcomes. Also, this review highlights groundbreaking carriers and delivery techniques that could revolutionize GBM management such as biomimetics, image guiding-drug delivery, and photodynamic and photothermal therapies for GBM management.

The Secretome of the Inductive Tooth Germ Exhibits Signals Required for Tooth Development

Teeth develop from reciprocal signaling between inductive and receptive cells. The inductive signals for tooth development are initially in the epithelium of the developing branchial arch, but later shift to the underlying mesenchyme of a developing tooth germ. The inductive signals that are needed for tooth development have not yet been fully identified. Our lab previously provided a basis for bioengineering new teeth by separating the tooth germ's epithelial and mesenchyme cells into a single cell population and recombing them. This approach, however, is not clinically applicable as the cells lose their inductive ability when expanded in vitro. In this study, we investigate whether the secretome and small extracellular vehicles (sEV) derived from inductive tooth germ mesenchyme can contribute to inductive signals required for tooth development. To address this, small extracellular vesicles and secretome were purified from inductive tooth germ mesenchyme and characterized. We investigated the proteome of sEV and proteome of inductive tooth germ mesenchyme and the impact of the culture condition and duration on the proteome. Additionally, we investigated the transcriptomic changes in tooth germ epithelium after treatment with sEV from inductive tooth germ mesenchyme. We show that culture duration of inductive tooth germ mesenchyme has an impact on the proteome of sEV purified from these cells. Similarly, culturing these cells in 2D and 3D environments results in different protein content. Proteome unique to sEV derived from inductive shows an association with multiple signaling pathways related to tooth development. Our RNASeq results show that treatment of tooth germ epithelial cells with small extracellular vesicles derived from inductive tooth germ mesenchyme results in an increased expression of some of the known odontogenic genes. Whilst further analysis is required to harvest the full potential of these sEV, our results suggests that extracellular vehicles contribute to signals required during tooth development, potentially through modulation of cellular metabolism and ECM organization.

Intranasal iron administration induces iron deposition, immunoactivation, and cell-specific vulnerability in the olfactory bulb of C57BL/6 mice

Iron is the most abundant transition metal in the brain and is essential for brain development and neuronal function; however, its abnormal accumulation is also implicated in various neurological disorders. The olfactory bulb (OB), an early target in neurodegenerative diseases, acts as a gateway for environmental toxins and contains diverse neuronal populations with distinct roles. This study explored the cell-specific vulnerability to iron in the OB using a mouse model of intranasal administration of ferric ammonium citrate (FAC). Olfactory function was assessed through olfactory discrimination tests, while iron levels in OB tissues, cerebrospinal fluid (CSF), and serum were quantified using inductively coupled plasma mass spectrometry (ICP-MS), immunohistochemical staining, and iron assays. Transcriptomic changes and immune responses were assessed using RNA sequencing and immune cell infiltration analysis. Results showed that intranasal FAC administration impaired olfactory function, accompanied by iron deposition in the olfactory mucosa and OB, as well as damage to olfactory sensory neurons. Notably, these effects occurred without elevations in CSF or serum iron levels. OB iron accumulation activated multiple immune cells, including microglia and astrocytes, but did not trigger ferroptosis. Spatial transcriptomic sequencing of healthy adult mouse OBs revealed significant cellular heterogeneity, with an abundance of neuroglia and neurons. Among neurons, GABAergic neurons were the most prevalent, followed by glutamatergic and dopaminergic neurons, while cholinergic and serotonergic neurons were sparsely distributed. Under iron-stressed conditions, oligodendrocytes, dopaminergic neurons, and glutamatergic neurons exhibited significant damage, while GABAergic neurons remained unaffected. These findings highlight the selective vulnerability of neuronal and glial populations to iron-induced stress, offering novel insights into the loss of specific cell types in the OB during iron dysregulation.

Exploring intranasal drug delivery via nanocarriers: A promising glioblastoma therapy

Glioblastoma is one of the most recurring types of glioma, having the highest mortality rate among all other gliomas. Traditionally, the standard course of treatment for glioblastoma involved maximum surgical resection, followed by chemotherapy and radiation therapy. Nanocarriers have recently focused on enhancing the chemotherapeutic administration to the brain to satisfy unmet therapeutic requirements for treating brain-related disorders. Due to the significant drawbacks and high recurrence rates of gliomas, intranasal administration of nanocarrier systems presents several advantages. These include low toxicity, non-invasiveness, and the ability to cross the blood-brain barrier. By customizing their size, encasing them with mucoadhesive agents, or undergoing surface modification that encourages movement over the nose's mucosa, we can exceptionally engineer nanocarriers for intranasal administration. Olfactory and trigeminal nerves absorb drugs administered nasally and transport them to the brain, serving as the primary delivery mechanism for nose-to-brain administration. This review sums up the latest developments in chemotherapeutic nanocarriers, such as metallic nanoparticles, polymeric nanoparticles, nanogels, nano vesicular carriers, genetic material-based nanocarriers, and polymeric micelles. These nanocarriers have demonstrated efficient drug delivery from the nose to the brain, effectively overcoming mucociliary clearance. However, challenges persist, such as limitations in targeted chemotherapy and restricted drug loading capacity for intranasal administration. Additionally, the review addresses regulatory considerations and prospects for these innovative drug delivery systems.

Non-Invasive Techniques of Nose to Brain Delivery Using Nanoparticulate Carriers: Hopes and Hurdles

Intranasal drug delivery route has emerged as a promising non-invasive method of administering drugs directly to the brain, bypassing the blood-brain barrier (BBB) and blood-cerebrospinal fluid barriers (BCSF). BBB and BCSF prevent many therapeutic molecules from entering the brain. Intranasal drug delivery can transport drugs from the nasal mucosa to the brain, to treat a variety of Central nervous system (CNS) diseases. Intranasal drug delivery provides advantages over invasive drug delivery techniques such as intrathecal or intraparenchymal which can cause infection. Many strategies, including nanocarriers liposomes, solid-lipid NPs, nano-emulsion, nanostructured lipid carriers, dendrimers, exosomes, metal NPs, nano micelles, and quantum dots, are effective in nose-to-brain drug transport. However, the biggest obstacles to the nose-to-brain delivery of drugs include mucociliary clearance, poor drug retention, enzymatic degradation, poor permeability, bioavailability, and naso-mucosal toxicity. The current review aims to compile current approaches for drug delivery to the CNS via the nose, focusing on nanotherapeutics and nasal devices. Along with a brief overview of the related pathways or mechanisms, it also covers the advantages of nasal drug delivery as a potential method of drug administration. It also offers several possibilities to improve drug penetration across the nasal barrier. This article overviews various in-vitro, ex-vivo, and in-vivo techniques to assess drug transport from the nasal epithelium into the brain.

Intranasal delivery of imaging agents to the brain

The potential of intranasal administered imaging agents to altogether bypass the blood-brain barrier offers a promising non-invasive approach for delivery directly to the brain. This review provides a comprehensive analysis of the advancements and challenges of delivering neuroimaging agents to the brain by way of the intranasal route, focusing on the various imaging modalities and their applications in central nervous system diagnostics and therapeutics. The various imaging modalities provide distinct insights into the pharmacokinetics, biodistribution, and specific interactions of imaging agents within the brain, facilitated by the use of tailored tracers and contrast agents. Methods: A comprehensive literature search spanned PubMed, Scopus, Embase, and Web of Science, covering publications from 1989 to 2024 inclusive. Starting with advancements in tracer development, we going to explore the rationale for integration of imaging techniques, and the critical role novel formulations such as nanoparticles, nano- and micro-emulsions in enhancing imaging agent delivery and visualisation. Results: The review highlights the use of innovative formulations in improving intranasal administration of neuroimaging agents, showcasing their ability to navigate the complex anatomical and physiological barriers of the nose-to-brain pathway. Various imaging techniques, MRI, PET, SPECT, CT, FUS and OI, were evaluated for their effectiveness in tracking these agents. The findings indicate significant improvements in brain targeting efficiency, rapid uptake, and sustained brain presence using innovative formulations. Conclusion: Future directions involve the development of optimised tracers tailored for intranasal administration, the potential of multimodal imaging approaches, and the implications of these advancements for diagnosing and treating neurological disorders.

Tau- and α-synuclein-targeted gold nanoparticles: applications, opportunities, and future outlooks in the diagnosis and therapy of neurodegenerative diseases

The use of nanomaterials in medicine offers multiple opportunities to address neurodegenerative disorders such as Alzheimer's and Parkinson's disease. These diseases are a significant burden for society and the health system, affecting millions of people worldwide without sensitive and selective diagnostic methodologies or effective treatments to stop their progression. In this sense, the use of gold nanoparticles is a promising tool due to their unique properties at the nanometric level. They can be functionalized with specific molecules to selectively target pathological proteins such as Tau and α-synuclein for Alzheimer's and Parkinson's disease, respectively. Additionally, these proteins are used as diagnostic biomarkers, wherein gold nanoparticles play a key role in enhancing their signal, even at the low concentrations present in biological samples such as blood or cerebrospinal fluid, thus enabling an early and accurate diagnosis. On the other hand, gold nanoparticles act as drug delivery platforms, bringing therapeutic agents directly into the brain, improving treatment efficiency and precision, and reducing side effects in healthy tissues. However, despite the exciting potential of gold nanoparticles, it is crucial to address the challenges and issues associated with their use in the medical field before they can be widely applied in clinical settings. It is critical to ensure the safety and biocompatibility of these nanomaterials in the context of the central nervous system. Therefore, rigorous preclinical and clinical studies are needed to assess the efficacy and feasibility of these strategies in patients. Since there is scarce and sometimes contradictory literature about their use in this context, the main aim of this review is to discuss and analyze the current state-of-the-art of gold nanoparticles in relation to delivery, diagnosis, and therapy for Alzheimer's and Parkinson's disease, as well as recent research about their use in preclinical, clinical, and emerging research areas.

Insights into Targeted and Stimulus-Responsive Nanocarriers for Brain Cancer Treatment

Brain cancers, especially glioblastoma multiforme, are associated with poor prognosis due to the limited efficacy of current therapies. Nanomedicine has emerged as a versatile technology to treat various diseases, including cancers, and has played an indispensable role in combatting the COVID-19 pandemic as evidenced by the role that lipid nanocarrier-based vaccines have played. The tunability of nanocarrier physicochemical properties -including size, shape, surface chemistry, and drug release kinetics- has resulted in the development of a wide range of nanocarriers for brain cancer treatment. These nanocarriers can improve the pharmacokinetics of drugs, increase blood-brain barrier transfer efficiency, and specifically target brain cancer cells. These unique features would potentially allow for more efficient treatment of brain cancer with fewer side effects and better therapeutic outcomes. This review provides an overview of brain cancers, current therapeutic options, and challenges to efficient brain cancer treatment. The latest advances in nanomedicine strategies are investigated with an emphasis on targeted and stimulus-responsive nanocarriers and their potential for clinical translation.

Intranasal Therapy in Palliative Care

In recent years, the use of the intranasal route has been actively explored as a possible drug delivery method in the palliative patient population. There are reports demonstrating the effectiveness of nasally administered medications that are routinely used in patients at the end of life. The subject of this study is the intranasal drug administration among palliative patients. The aim is to summarize currently used intranasal therapies among palliative patients, determine the benefits and difficulties, and identify potential areas for future research. A review of available medical literature published between 2013 and 2023 was performed using online scientific databases. The following descriptors were used when searching for articles: "palliative", "intranasal", "nasal", "end-of-life care", "intranasal drug delivery" and "nasal drug delivery". Out of 774 articles, 55 directly related to the topic were finally selected and thoroughly analyzed. Based on the bibliographic analysis, it was shown that drugs administered intranasally may be a good, effective, and convenient form of treatment for patients receiving palliative care, in both children and adults. This topic requires further, high-quality clinical research.

Nanotechnology for enhanced nose-to-brain drug delivery in treating neurological diseases

Despite the increasing global incidence of brain disorders, achieving sufficient delivery towards the central nervous system (CNS) remains a formidable challenge in terms of translating into improved clinical outcomes. The brain is highly safeguarded by physiological barriers, primarily the blood-brain barrier (BBB), which routinely excludes most therapeutics from entering the brain following systemic administration. Among various strategies investigated to circumvent this challenge, intranasal administration, a noninvasive method that bypasses the BBB to allow direct access of drugs to the CNS, has been showing promising results. Nanotechnology-based drug delivery systems, in particular, have demonstrated remarkable capacities in overcoming the challenges posed by nose-to-brain drug delivery and facilitating targeted drug accumulation within the brain while minimizing side effects of systemic distribution. This review comprehensively summarizes the barriers of nose-to-brain drug delivery, aiming to enhance our understanding of potential physiological obstacles and improve the efficacy of nasal delivery in future trials. We then highlight cutting-edge nanotechnology-based studies that enhance nose-to-brain drug delivery in three key aspects, demonstrating substantial potential for improved treatment of brain diseases. Furthermore, the attention towards clinical studies will ease the regulatory approval process for nasal administration of nanomedicines targeting brain disease.

Overcoming challenges in glioblastoma treatment: targeting infiltrating cancer cells and harnessing the tumor microenvironment

Glioblastoma (GB) is a highly malignant primary brain tumor with limited treatment options and poor prognosis. Despite current treatment approaches, including surgical resection, radiation therapy, and chemotherapy with temozolomide (TMZ), GB remains mostly incurable due to its invasive growth pattern, limited drug penetration beyond the blood-brain barrier (BBB), and resistance to conventional therapies. One of the main challenges in GB treatment is effectively eliminating infiltrating cancer cells that remain in the brain parenchyma after primary tumor resection. We've reviewed the most recent challenges and surveyed the potential strategies aimed at enhancing local treatment outcomes.

Exploration of inorganic nanoparticles for revolutionary drug delivery applications: a critical review

The nanosystems for delivering drugs which have evolved with time, are being designed for greater drug efficiency and lesser side-effects, and are also complemented by the advancement of numerous innovative materials. In comparison to the organic nanoparticles, the inorganic nanoparticles are stable, have a wide range of physicochemical, mechanical, magnetic, and optical characteristics, and also have the capability to get modified using some ligands to enrich their attraction towards the molecules at the target site, which makes them appealing for bio-imaging and drug delivery applications. One of the strong benefits of using the inorganic nanoparticles-drug conjugate is the possibility of delivering the drugs to the affected cells locally, thus reducing the side-effects like cytotoxicity, and facilitating a higher efficacy of the therapeutic drug. This review features the direct and indirect effects of such inorganic nanoparticles like gold, silver, graphene-based, hydroxyapatite, iron oxide, ZnO, and CeO2 nanoparticles in developing effective drug carrier systems. This article has remarked the peculiarities of these nanoparticle-based systems in pulmonary, ocular, wound healing, and antibacterial drug deliveries as well as in delivering drugs across Blood-Brain-Barrier (BBB) and acting as agents for cancer theranostics. Additionally, the article sheds light on the plausible modifications that can be carried out on the inorganic nanoparticles, from a researcher's perspective, which could open a new pathway.