Curing the Toxicity of Multi-Walled Carbon Nanotubes through Native Small-molecule Drugs

CNT and Graphene-Based Transistor Biosensors for Cancer Detection: A Review

An essential aspect of successful cancer diagnosis is the identification of malignant tumors during the early stages of development, as this can significantly diminish patient mortality rates and increase their chances of survival. This task is facilitated by cancer biomarkers, which play a crucial role in determining the stage of cancer cells, monitoring their growth, and evaluating the success of treatment. However, conventional cancer detection methods involve several intricate steps, such as time-consuming nucleic acid amplification, target detection, and a complex treatment process that may not be appropriate for rapid screening. Biosensors are emerging as promising diagnostic tools for detecting cancer, and carbon nanotube (CNT)- and graphene-based transistor biosensors have shown great potential due to their unique electrical and mechanical properties. These biosensors have high sensitivity and selectivity, allowing for the rapid detection of cancer biomarkers at low concentrations. This review article discusses recent advances in the development of CNT- and graphene-based transistor biosensors for cancer detection.

Carbon Nanotubes as Carriers in Drug Delivery for Non-Small Cell Lung Cancer, Mechanistic Analysis of Their Carcinogenic Potential, Safety Profiling and Identification of Biomarkers

Non-small cell lung cancer (NSCLC) is a global burden leading to millions of deaths worldwide every year. Nanomedicine refers to the use of materials at the nanoscale for drug delivery and subsequent therapeutic approaches in cancer. Carbon nanotubes (CNTs) are widely used as nanocarriers for therapeutic molecules such as plasmids, siRNAs, antisense agents, aptamers and molecules related to the immunotherapy for several cancers. They are usually functionalized and loaded with standard drug molecules to improve their therapeutic efficiency. Functionalization and drug loading possibly decrease the genotoxic and carcinogenic potential of CNTs. In addition, the targeted cytotoxic properties of the drug improve and undesired toxicity decreases after drug loading and/or conjugation with proteins, including antibodies. For intended drug delivery, a lysosomal pH of 5.5 is more suitable and effective for the slow and extended release of cytotoxic drugs than a physiological of pH 7.4. Remarkably, CNTs possess intrinsic antitumor properties and are usually internalized by endocytosis. After being internalized, several mechanisms are involved in the therapeutic and carcinogenic effects of CNTs. They are generally safe for therapy, and their toxicity profile remains dependent on their physicochemical properties. Moreover, the dose, route, duration of exposure, surface properties and degradative potential determine the toxicity outcomes of CNTs locally or systemically. In summary, the use of CNTs in drug delivery and NSCLC therapy, as well as their genotoxic and carcinogenic potential and the possible mechanisms, has been discussed in this review. The therapeutic index is generally high for NSCLC cells treated with drug-loaded CNTs; therefore, they are effective carriers in implementing targeted therapy for NSCLC.

Decadal Journey of CNT-Based Analytical Biosensing Platforms in the Detection of Human Viruses

It has been proven that viral infections pose a serious hazard to humans and also affect social health, including morbidity and mental suffering, as illustrated by the COVID-19 pandemic. The early detection and isolation of virally infected people are, thus, required to control the spread of viruses. Due to the outstanding and unparalleled properties of nanomaterials, numerous biosensors were developed for the early detection of viral diseases via sensitive, minimally invasive, and simple procedures. To that aim, viral detection technologies based on carbon nanotubes (CNTs) are being developed as viable alternatives to existing diagnostic approaches. This article summarizes the advancements in CNT-based biosensors since the last decade in the detection of different human viruses, namely, SARS-CoV-2, dengue, influenza, human immunodeficiency virus (HIV), and hepatitis. Finally, the shortcomings and benefits of CNT-based biosensors for the detection of viruses are outlined and discussed.

Carbon Nanotubes Induce Metabolomic Profile Disturbances in Zebrafish: NMR-Based Metabolomics Platform

The present study aims to investigate the metabolic effects of single-walled carbon nanotubes (SWCNT) on zebrafish (Danio rerio) using ¹H nuclear magnetic resonance (¹H-NMR) spectroscopy. However, there is no significant information available regarding the characterization of organic molecules, and metabolites with SWCNT exposure. Noninvasive biofluid methods have improved our understanding of SWCNT metabolism in zebrafish in recent years. Here, we used targeted metabolomics to quantify a set of metabolites within biological systems. SWCNT at various concentrations was given to zebrafish, and the metabolites were extracted using two immiscible solvent systems, methanol and chloroform. Metabolomics profiling was used in association with univariate and multivariate data analysis to determine metabolomic phenotyping. The metabolites, malate, oxalacetate, phenylaniline, taurine, sn-glycero-3-phosphate, glycine, N-acetyl mate, lactate, ATP, AMP, valine, pyruvate, ADP, serine, niacinamide are significantly impacted. The metabolism of amino acids, energy and nucleotides are influenced by SWCNT which might indicate a disturbance in metabolic reaction networks. In conclusion, using high-throughput analytical methods, we provide a perspective of metabolic impacts and the underlying associated metabolic pathways.

Toxicity of Carbon Nanotubes: Molecular Mechanisms, Signaling Cascades, and Remedies in Biomedical Applications

Carbon nanotubes (CNTs) are the most studied allotropic form of carbon. They can be used in various biomedical applications due to their novel physicochemical properties. In particular, the small size of CNTs, with a large surface area per unit volume, has a considerable impact on their toxicity. Despite of the use of CNTs in various applications, toxicity is a big problem that requires more research. In this Review, we discuss the toxicity of CNTs and the associated mechanisms. Physicochemical factors, such as metal impurities, length, size, solubilizing agents, CNTs functionalization, and agglomeration, that may lead to oxidative stress, toxic signaling pathways, and potential ways to control these mechanisms are also discussed. Moreover, with the latest mechanistic evidence described in this Review, we expect to give new insights into CNTs' toxicological effects at the molecular level and provide new clues for the mitigation of harmful effects emerging from exposure to CNTs.

Toxicity of multi-wall carbon nanotubes inhalation on the brain of rats

This study was designed to investigate the brain toxicity following the respiratory contact with multi-wall carbon nanotubes (MWCNTs) in male Wistar rats. Rats were exposed to 5 mg/m³ MWCNT aerosol in different sizes and purities for 5 h/day, 5 days/week for 2 weeks in a whole-body exposure chamber. After 2-week exposure, mitochondrial isolation was performed from different parts of rat brain (hippocampus, frontal cortex, and cerebellum) and parameters of mitochondrial toxicity including mitochondrial succinate dehydrogenase (SDH) activity, generation of reactive oxygen species (ROS), mitochondrial membrane potential (MMP) collapse, mitochondrial swelling, and cytochrome c release, ATP level, mitochondrial GSH, and lipid peroxidation were evaluated. Our results demonstrated that MWCNTs with different characteristics, in size and purity, significantly (P < 0.05) decreased SDH activity, GSH, and ATP level, and increased mitochondrial ROS production, lipid peroxidation, mitochondrial swelling, MMP collapse, and cytochrome c release in the brain mitochondria. In conclusion, we suggested that MWCNTs with different characteristics, in size and purity, induce damage in varying degrees on the mitochondrial respiratory chain and increase mitochondrial ROS formation in different parts of rat brain (hippocampus, frontal cortex, and cerebellum).

Nanomaterials and Their Negative Effects on Human Health

Mesostructured silica, dendrimers, and allotropes of carbon were exhaustively used in biomedical, cosmetics, semiconductors, and food industry applications. Considering the huge prospect of nanomaterials, their potential hazards on exposure to humans and their related ecotoxicological effects needs to be summarized. Nanoparticles with size below 100 nm could pass into the lung and then to blood through inhalation, ingestion, and skin contact. As nanotechnology innovation is expected to achieve $ 2231 million by 2025, humans will be exposed ever increasingly in day-to-day life and in industries. In this review, the latest synthetic methodology of silica, dendrimers, and CNTs, their biological applications (in vitro and in vivo) related to toxicity were discussed. In terms of structured silica, the toxic and non-toxic effect induced by specific templates (cetylpyridinium bromide, cetyltrimethylammonium bromide, dipalmitoylphosphatidylcholine, C16L-tryptophan, C16-L-histidine, and C16-L-poline) that are used to generate mesoporous silica, silica nanoparticle sizes (25, 50, 60, 115, and 500 nm), and silane functionalization (NH₂ and COOH) were discussed. The recent applications of different generations (G3, G4, G5, and G6) of amphiphilic Janus dendrimers were discussed along with toxicity effect of different charged dendrimers (cationic and anionic) and effect of PEGylation. Recent synthesis, advantages, and disadvantages of carbon nanotubes (CNTs) were presented for structures like single walled carbon nanotubes (SWCNTs) and multiwalled carbon nanotubes (MWCNTs). The influence of diameter of SWCNTs (linear and short), thickness (thin and thick), effect of oxidation, metal oxide species (TiO₂, Fe, and Au), and biocompatible polymers (polyethylene glycol, bisphosphonate, and alendronate) were shown in relation to molecular pathways in animal cells.

Recent advances in graphene-based nanomaterials: properties, toxicity and applications in chemistry, biology and medicine

This review (with 239 refs.) summarizes the progress that has been made in applications of graphene-based nanomaterials (such as plain graphene, graphene oxides, doped graphene oxides, graphene quantums dots) in biosensing, imaging, drug delivery and diagnosis. Following an introduction into the field, a first large section covers the toxicity of graphene and its derivatives (with subsections on bacterial toxicity and tissue toxicity). The use of graphene-based nanomaterials in sensors is reviewed next, with subsections on electrochemical, FET-based, fluorescent, chemiluminescent and colorimetric sensors and probes. The large field of imaging is treated next, with subchapters on optical, PET-based, and magnetic resonance based methods. A concluding section summarizes the current status, addresses current challenges, and gives an outlook on potential future trends. Graphical Abstract Schematic presentation of the potential applications of graphene-based materials in life science and biomedicine, emphatically reflected in some vital areas such as DNA analysis, biological monitoring, drug delivery, in vitro labelling, in vivo imaging, tumor target, etc.

The Advances in Biomedical Applications of Carbon Nanotubes

Unique chemical, physical, and biological features of carbon nanotubes make them an ideal candidate for myriad applications in industry and biomedicine. Carbon nanotubes have excellent electrical and thermal conductivity, high biocompatibility, flexibility, resistance to corrosion, nano-size, and a high surface area, which can be tailored and functionalized on demand. This review discusses the progress and main fields of bio-medical applications of carbon nanotubes based on recently-published reports. It encompasses the synthesis of carbon nanotubes and their application for bio-sensing, cancer treatment, hyperthermia induction, antibacterial therapy, and tissue engineering. Other areas of carbon nanotube applications were out of the scope of this review. Special attention has been paid to the problem of the toxicity of carbon nanotubes.

Towards the Extraction of Radioactive Cesium-137 from Water via Graphene/CNT and Nanostructured Prussian Blue Hybrid Nanocomposites: A Review

Cesium is a radioactive fission product generated in nuclear power plants and is disposed of as liquid waste. The recent catastrophe at the Fukushima Daiichi nuclear plant in Japan has increased the 137Cs and 134Cs concentrations in air, soil and water to lethal levels. 137Cs has a half-life of 30.4 years, while the half-life of 134Cs is around two years, therefore the formers' detrimental effects linger for a longer period. In addition, cesium is easily transported through water bodies making water contamination an urgent issue to address. Presently, efficient water remediation methods towards the extraction of 137Cs are being studied. Prussian blue (PB) and its analogs have shown very high efficiencies in the capture of 137Cs+ ions. In addition, combining them with magnetic nanoparticles such as Fe3O4 allows their recovery via magnetic extraction once exhausted. Graphene and carbon nanotubes (CNT) are the new generation carbon allotropes that possess high specific surface areas. Moreover, the possibility to functionalize them with organic or inorganic materials opens new avenues in water treatment. The combination of PB-CNT/Graphene has shown enhanced 137Cs+ extraction and their possible applications as membranes can be envisaged. This review will survey these nanocomposites, their efficiency in 137Cs+ extraction, their possible toxicity, and prospects in large-scale water remediation and succinctly survey other new developments in 137Cs+ extraction.

Evaluation of the resistance to bacterial growth of star-shaped poly(ε-caprolactone)-co-poly(ethylene glycol) grafted onto functionalized carbon nanotubes nanocomposites

Nanocomposites of functionalized carbon nanotubes (CNTs_f) as nanofillers, and a copolymer of star-shaped poly(ε-caprolactone) (stPCL) and poly(ethylene glycol) (PEG) as a polymeric matrix were synthesized, characterized, and their resistance to the growth of Staphylococcus aureus and Pseudomonas aeruginosa was evaluated. CNTs_f contain hydroxyl, carboxyl and acyl chloride groups attached to their surface. Nanocomposites were prepared by mixing CNTs_f to a solution of stPCL-PEG copolymer. Raman and FT-IR spectroscopies confirm the functionalization of carbon nanotubes (CNTs). Star-shaped PCL-PEG copolymer was characterized by Gel permeation chromatography (GPC), and ¹H-NMR and ¹³C-NMR spectroscopies. X-ray photoelectron spectroscopy (XPS) shows that CNTs_f are grafted to the stPCL-PEG copolymer. Crystallization behavior of the nanocomposites depends on the amount of CNTs_f used in their preparation, detecting nucleation (nanocomposites prepared with 0.5 wt.% of CNTs_f) or anti-nucleation (nanocomposites prepared with 1.0 wt.% of CNTs_f) effects. Young's Moduli and thermal stability of nanocomposites were higher, but their resistence to the proliferation of Staphylococcus aureus and Pseudomonas aeruginosa was lower than the observed for their pure polymer matrix.

Ocular toxicity of reduced graphene oxide or graphene oxide exposure in mouse eyes

With the wide application and mass production of nanoparticle products, environmental nanopollutants will become increasingly common. The eye is an important organ responsible for vision in most living organisms, and it is directly exposed to the atmosphere. Direct contact between the eye and nanoparticles in the environment can potentially lead to ocular damage. However, publications focusing on the eye-damaging potential of nanoparticles are scarce. Therefore, to evaluate the impact of nanoparticles on the eyes, we investigated the ocular toxicity of reduced graphene oxide (RGO) and graphene oxide (GO) using morphological and molecular biological methods in vivo and in vitro in the present work. The findings show that short-term repeated GO exposure can cause obvious intraocular inflammation, an incrassated corneal stromal layer, cell apoptosis in the cornea, iris neovascularization and significant cytotoxicity of rat corneal epithelial cells (rCECs), while RGO causes no significant ocular toxicity in mice.