Distribution in the brain and possible neuroprotective effects of intranasally delivered multi-walled carbon nanotubes

UV-Vis quantification of the iron content in iteratively steam and HCl purified single-walled carbon nanotubes

As-produced carbon nanotubes contain impurities which can dominate the properties of the material and are thus undesired. Herein we present a multi-step purification treatment that combines the use of steam and hydrochloric acid in an iterative manner. This allows the reduction of the iron content down to 0.2 wt. % in samples of single-walled carbon nanotubes (SWCNTs). Remarkably, Raman spectroscopy analysis reveals that this purification strategy does not introduce structural defects into the SWCNTs' backbone. To complete the study, we also report on a simplified approach for the quantitative assessment of iron using UV-Vis spectroscopy. The amount of metal in SWCNTs is assessed by dissolving in HCl the residue obtained after the complete combustion of the sample. This leads to the creation of hexaaquairon(III) chloride which allows the determination of the amount of iron, from the catalyst, by UV-Vis spectroscopy. The main advantage of the proposed strategy is that it does not require the use of additional complexing agents.

Nasal Delivery to the Brain: Harnessing Nanoparticles for Effective Drug Transport

The nose-to-brain drug-delivery system has emerged as a promising strategy to overcome the challenges associated with conventional drug administration for central nervous system disorders. This emerging field is driven by the anatomical advantages of the nasal route, enabling the direct transport of drugs from the nasal cavity to the brain, thereby circumventing the blood-brain barrier. This review highlights the significance of the anatomical features of the nasal cavity, emphasizing its high permeability and rich blood supply that facilitate rapid drug absorption and onset of action, rendering it a promising domain for neurological therapeutics. Exploring recent developments and innovations in different nanocarriers such as liposomes, polymeric nanoparticles, solid lipid nanoparticles, dendrimers, micelles, nanoemulsions, nanosuspensions, carbon nanotubes, mesoporous silica nanoparticles, and nanogels unveils their diverse functions in improving drug-delivery efficiency and targeting specificity within this system. To minimize the potential risk of nanoparticle-induced toxicity in the nasal mucosa, this article also delves into the latest advancements in the formulation strategies commonly involving surface modifications, incorporating cutting-edge materials, the adjustment of particle properties, and the development of novel formulations to improve drug stability, release kinetics, and targeting specificity. These approaches aim to enhance drug absorption while minimizing adverse effects. These strategies hold the potential to catalyze the advancement of safer and more efficient nose-to-brain drug-delivery systems, consequently revolutionizing treatments for neurological disorders. This review provides a valuable resource for researchers, clinicians, and pharmaceutical-industry professionals seeking to advance the development of effective and safe therapies for central nervous system disorders.

Carbon nanotubes as neuroprotective agents

Carbon nanotubes, an emerging class of carbon nanomaterials, possess tremendous potential for application in biotechnology and biomedicine particularly in neurological disorders. Carbon nanotubes owing to their fascinating properties have the potential to revolutionize medicine and technology, particularly in the realm of drug delivery, biosensing, bioimaging, and as therapeutic agents to tackle complex neurological disorders such as Alzheimer's and Parkinson's disease. In this review, a summary of the use of carbon nanotubes for neuropathological outcomes such as alleviating oxidative stress and amyloid formation, which are well-studied molecular outcomes associated with Alzheimer's and Parkinson's disease. In the end, challenges associated with the clinical testing of carbon nanotubes and possible ways to overcome them are highlighted.

Intranasal delivery of mitochondria targeted neuroprotective compounds for traumatic brain injury: screening based on pharmacological and physiological properties

Targeting drugs to the mitochondrial level shows great promise for acute and chronic treatment of traumatic brain injury (TBI) in both military and civilian sectors. Perhaps the greatest obstacle to the successful delivery of drug therapies is the blood brain barrier (BBB). Intracerebroventricular and intraparenchymal routes may provide effective delivery of small and large molecule therapies for preclinical neuroprotection studies. However, clinically these delivery methods are invasive, and risk inadequate exposure to injured brain regions due to the rapid turnover of cerebral spinal fluid. The direct intranasal drug delivery approach to therapeutics holds great promise for the treatment of central nervous system (CNS) disorders, as this route is non-invasive, bypasses the BBB, enhances the bioavailability, facilitates drug dose reduction, and reduces adverse systemic effects. Using the intranasal method in animal models, researchers have successfully reduced stroke damage, reversed Alzheimer's neurodegeneration, reduced anxiety, improved memory, and delivered neurotrophic factors and neural stem cells to the brain. Based on literature spanning the past several decades, this review aims to highlight the advantages of intranasal administration over conventional routes for TBI, and other CNS disorders. More specifically, we have identified and compiled a list of most relevant mitochondria-targeted neuroprotective compounds for intranasal administration based on their mechanisms of action and pharmacological properties. Further, this review also discusses key considerations when selecting and testing future mitochondria-targeted drugs given intranasally for TBI.

Functionalised Carbon Nanotubes: Promising Drug Delivery Vehicles for Neurovascular Disorder Intervention

Neurovascular diseases are linked to the brain's blood vessels. These disorders are complicated to treat due to the strict selective characteristics of the blood-brain barrier. Consequently, the potency of the pharmacological treatments for these conditions is immensely diminished, leading to a rise in neurovascular-associated morbidity and mortality. Carbon nanotubes are regarded as essential nanoparticles with a promise of treating neurovascular disorders. Current findings have demonstrated the effectiveness of carbon nanotubes as vehicles for ferrying drugs to the site of interest. This review accentuates the theoretical utilisation of carbon nanotubes as drug nanocarriers equipped with the penetrating capability to the blood-brain barrier for treating neurovascular disorders such as ischemic stroke. The success of the carbon nanotube system may result in the development of a new and highly relevant drug delivery procedure. This review will also cover carbon nanotube functionalisation for applications in the biomedical fields, toxicity, in vitro and in vivo drugs and biomolecule delivery, and the future outlook of carbon nanotubes.

Nasal delivery of neurotherapeutics via nanocarriers: Facets, aspects, and prospects

Alzheimer’s disease (AD) is one of the neurological ailments which continue to represent a major public health challenge, owing to increased life expectancy and aging population. Progressive memory loss and decrease in cognitive behavior, owing to irreversible destruction of neurons along with expensive therapeutic interventions, call for an effective, alternate, yet affordable treatment for Alzheimer’s disease. Safe and effective delivery of neurotherapeutics in Alzheimer’s like central nervous system (CNS) disorders still remains elusive despite the major advances in both neuroscience and drug delivery research. The blood–brain barrier (BBB) with its tight endothelial cell layer surrounded by astrocyte foot processes poses as a major barrier for the entry of drugs into the brain. Nasal drug delivery has emerged as a reliable method to bypass this blood–brain barrier and deliver a wide range of neurotherapeutic agents to the brain effectively. This nasal route comprises the olfactory or trigeminal nerves originating from the brain and terminating into the nasal cavity at the respiratory epithelium or olfactory neuroepithelium. They represent the most direct method of noninvasive entry into the brain, opening the most suitable therapeutic avenue for treatment of neurological diseases. Also, drugs loaded into nanocarriers can have better interaction with the mucosa that assists in the direct brain delivery of active molecules bypassing the BBB and achieving rapid cerebrospinal fluid levels. Lipid particulate systems, emulsion-based systems, vesicular drug delivery systems, and other nanocarriers have evolved as promising drug delivery approaches for the effective brain delivery of anti-Alzheimer’s drugs with improved permeability and bioavailability via the nasal route. Charge, size, nature of neurotherapeutics, and formulation excipients influence the effective and targeted drug delivery using nanocarriers via the nasal route. This article elaborates on the recent advances in nanocarrier-based nasal drug delivery systems for the direct and effective brain delivery of the neurotherapeutic molecules. Additionally, we have attempted to highlight various experimental strategies, underlying mechanisms in the pathogenesis and therapy of central nervous system diseases, computational approaches, and clinical investigations pursued so far to attain and enhance the direct delivery of therapeutic agents to the brain via the nose-to-brain route, using nanocarriers.

Use of electroconductive biomaterials for engineering tissues by 3D printing and 3D bioprinting

Existing methods of engineering alternatives to restore or replace damaged or lost tissues are not satisfactory due to the lack of suitable constructs that can fit precisely, function properly and integrate into host tissues. Recently, three-dimensional (3D) bioprinting approaches have been developed to enable the fabrication of pre-programmed synthetic tissue constructs that have precise geometries and controlled cellular composition and spatial distribution. New bioinks with electroconductive properties have the potential to influence cellular fates and function for directed healing of different tissue types including bone, heart and nervous tissue with the possibility of improved outcomes. In the present paper, we review the use of electroconductive biomaterials for the engineering of tissues via 3D printing and 3D bioprinting. Despite significant advances, there remain challenges to effective tissue replacement and we address these challenges and describe new approaches to advanced tissue engineering.