The Puzzling Potential of Carbon Nanomaterials: General Properties, Application, and Toxicity

Nanocellulose: The Ultimate Green Aqueous Dispersant for Nanomaterials

Nanocellulose, a nanoscale derivative from renewable biomass sources, possesses remarkable colloidal properties in water, mechanical strength, and biocompatibility. It emerges as a promising bio-based dispersing agent for various nanomaterials in water. This mini-review explores the interaction between cellulose nanomaterials (nanocrystals or nanofibers) and water, elucidating how this may enable their potential as an eco-friendly dispersing agent. We explore the potential of nanocellulose derived from top-down processes, nanocrystals, and nanofibers for dispersing carbon nanomaterials, semiconducting oxide nanoparticles, and other nanomaterials in water. We also highlight its advantages over traditional methods by not only effectively dispersing those nanomaterials but also potentially eliminating the need for further chemical treatments or supporting stabilizers. This not only preserves the exceptional properties of nanomaterials in aqueous dispersion, but may even lead to the emergence of novel hybrid functionalities. Overall, this mini-review underscores the remarkable versatility of nanocellulose as a green dispersing agent for a variety of nanomaterials, inspiring further research to expand its potential to other nanomaterials and applications.

The impact of fullerenol nanoparticles on the growth of toxigenic Aspergillus flavus and aflatoxins production in vitro and in corn flour

Antifungal and antimycotoxigenic activity of fullerenol nanoparticles (FNPs) were investigated on Aspergillus flavus growth isolated from a real food sample and aflatoxins (AFs) (AFB1 and AFB2 ) production. The final FNPs concentrations in in vitro and in commercial corn flour after the stationary incubation period of 7 and 14 days were in the range 0.16-80 µg/mL and 0.16-80 µg/g, respectively. Nanocharacterization of FNPs revealed an average size of 5-20 nm and a zeta potential of -35 mV. The highest degree of A. flavus mycelium growth inhibition (28%) after 7 days was observed for applied FNP concentration of 8.0 µg/mL, while after 14 days FNP concentration of 0.32 µg/mL led to the maximal inhibition of A. flavus mycelium growth (36%). Spearman's correlations analysis revealed a strong positive correlation between AFB1 and AFB2 concentrations in YES broth after 7 (R = 0.994, p < 0.05) and 14 days (R = 0.976), as well as between AFs concentrations and A. flavus mycelium mass after 7 (R = 0.786 for AFB1 and R = 0.766 for AFB2 ) and 14 days (R = 0.810 for AFB1 and R = 0.833 for AFB2 ). Paired samples t-test showed the existence of a statistically significant difference (p < 0.05) between the produced AFs concentrations after the incubation of 7 and 14 days. Regarding the artificially inoculated corn flour the lower applied FNP concentrations (0.16-0.8 µg/g) achieved a reduction of AFB1 up to 42% and 60% after 7 and 14 days, respectively.

Therapeutic applications of carbon nanomaterials in renal cancer

Carbon nanomaterials (CNMs), including carbon nanotubes (CNTs), graphene, and nanodiamonds (NDs), have shown great promise in detecting and treating numerous cancers, including kidney cancer. CNMs can increase the sensitivity of diagnostic techniques for better kidney cancer identification and surveillance. They enable targeted medicine delivery specifically to tumour locations, with little effect on healthy tissue. Because of their unique chemical and physical characteristics, they can avoid the body's defence mechanisms, making it easier to accumulate where tumours exist. Consequently, CNMs provide more effective drug delivery to kidney cancer cells. It also helps in improving the efficacy of treatment. This review explores the potential of several CNMs in improving therapeutic strategies for kidney cancer. We briefly covered the physicochemical properties and therapeutic applications of CNMs. Additionally, we discussed how structural modifications in CNMs enhance their precision in treating renal cancer. A thorough overview of CNM-based gene, peptide, and drug delivery strategies for the treatment of renal cancer is presented in this review. It covers information on other CNM-based therapeutic approaches, such as hyperthermia, photodynamic therapy, and photoacoustic therapy. Also, the interactions of CNMs with the tumour microenvironment (TME) are explored, including modulation of the immune response, regulation of tumour hypoxia, interactions between CNMs and TME cells, effects of TME pH on CNMs, and more. Finally, potential side effects of CNMs, such as toxicity, bio corona formation, enzymatic degradation, and biocompatibility, are also discussed.

Potential Efficacy of Herbal Medicine-Derived Carbon Dots in the Treatment of Diseases: From Mechanism to Clinic

Carbon dots (CDs), a crucial component of nanomaterials, are zero-dimensional nanomaterials with carbon as the backbone structure and smaller than 10 nm. Due to their beneficial characteristics, they are widely used in biomedical fields such as biosensors, drug delivery, bio-imaging, and interactions with DNA. Interestingly, a novel type of carbon dot, generated by using herbal medicines as synthetic raw materials, has emerged as the most recent incomer in the family of CDs with the extensive growth in the number of materials selected for carbon dots synthesis. Herbal medicine-derived carbon dots (HM-CDs) have been employed in the biomedical industry, and are rapidly emerging as "modern nanomaterials" due to their unique structures and exceptional capabilities. Emerging trends suggest that their specific properties can be used in bleeding disorders, gastrointestinal disorders, inflammation-related diseases, and other common intractable diseases including cancer, menopausal syndrome, central nervous system disorders, and pain of various forms and causes. In addition, HM-CDs have been found to have organ-protective and antioxidant properties, as evidenced by extensive studies. This research provides a more comprehensive understanding of the biomedical applications of HM-CDs for the aforementioned disorders and investigates the intrinsic pharmacological activities and mechanisms of these HM-CDs to further advance their clinical applications.

Unveiling the Effects of Carbon-Based Nanomaterials on Crop Growth: From Benefits to Detriments

To systematically assess the impact of typical CNMs on the growth effects of cereal crops, we conducted a meta-analysis of 48 independent studies worldwide. The pooled results showed that shoot weight (13.39%) and antioxidant metabolite content (SOD: 106.32%, POD: 32.29%, CAT: 22.63%) of cereal crops exposed to the presence of CNMs were significantly increased, but phytohormones secretion (17.84%) was inhibited. The results of subgroup analysis showed that there were differences in the results of different CNM types with the same exposure concentration on growth effects. Short-term exposure adversely affected the root and photosynthetic capacity of the crop, but prolonged exposure instead showed a promoting effect. Multiple linear regression analysis showed that the concentration of CNMs and cereal variety variables were significantly associated with changes in multiple growth effect values. This work could offer references and fresh perspectives for investigating how nanoparticles and crops interact.

In vitro and in silico studies of the antiviral activity of polyhydrated fullerenes against influenza A (H1N1) virus

As of today, influenza viruses remain a relevant target for the development of antiviral compounds due to their rapid evolution and acquisition of the resistance to existing drugs. Fullerene derivatives have already shown the ability to successfully interact with viruses, and polyhydrated fullerenes (or fullerenols) are particularly attractive due to their compatibility with biological fluids and low toxicity. Therefore, the goal of this work was to study the effect of two batches of a mixture of polyhydrated fullerenes with a mass ratio of 78.1% C₆₀/C₇₀ and 21.9% C₇₆/C₇₈/C₈₄ on the influenza A (H1N1) virus. It was determined that the mixture of fullerenols, along with the low toxicity, showed high antiviral activity with a decrease in the viral infectious titer up to 4 orders of magnitude. In addition, studied fullerenols did not affect the hemagglutination process and did not show any significant prophylactic activity. With the help of molecular docking and molecular dynamics simulation, the likely target of fullerenols' action was determined-the binding site of the RNA primer of the viral RNA-dependent RNA polymerase. Therefore, we assume that the high antiviral effect of polyhydrated fullerenes on influenza A virus is related to their interaction with the viral RNA polymerase.

Potential Role of Carbon Nanomaterials in the Treatment of Malignant Brain Gliomas

Malignant gliomas are the most common primary brain tumors in adults up to an extent of 78% of all primary malignant brain tumors. However, total surgical resection is almost unachievable due to the considerable infiltrative ability of glial cells. The efficacy of current multimodal therapeutic strategies is, furthermore, limited by the lack of specific therapies against malignant cells, and, therefore, the prognosis of these in patients is still very unfavorable. The limitations of conventional therapies, which may result from inefficient delivery of the therapeutic or contrast agent to brain tumors, are major reasons for this unsolved clinical problem. The major problem in brain drug delivery is the presence of the blood-brain barrier, which limits the delivery of many chemotherapeutic agents. Nanoparticles, thanks to their chemical configuration, are able to go through the blood-brain barrier carrying drugs or genes targeted against gliomas. Carbon nanomaterials show distinct properties including electronic properties, a penetrating capability on the cell membrane, high drug-loading and pH-dependent therapeutic unloading capacities, thermal properties, a large surface area, and easy modification with molecules, which render them as suitable candidates for deliver drugs. In this review, we will focus on the potential effectiveness of the use of carbon nanomaterials in the treatment of malignant gliomas and discuss the current progress of in vitro and in vivo researches of carbon nanomaterials-based drug delivery to brain.

Toxicity of micro(nano)plastics with different size and surface charge on human nasal epithelial cells and rats via intranasal exposure

Micro (nano)plastics (MNPs) have become emerging environmental contaminants, yet their toxicity and systemic effects via intranasal exposure remain unclear. This study investigated the in vitro toxicity of thirteen polystyrene MNPs with different surface functionalization (carboxylic (C-PS), amino (A-PS), and bare (PS)) and sizes (20-2000 nm) on human nasal epithelial cells (HNEpCs) at 10-1250 μg/mL as well as their in vivo toxicity to rats via intranasal administration at 125 μg/mL. The in vitro study showed that PS20, PS50, A-PS50, PS500, and A-PS500 significantly inhibited cell viability, which was dependent on particle concentration. A-PS induced higher cytotoxicity than C-PS and PS, and most MNPs inhibited cell proliferation after 24-h. Flow cytometry analysis suggested that PS induced cell apoptosis, while A-PS caused cell necrosis. MNPs were phagocytosed by HNEpCs and entered nucleus. The in vivo study showed that MNPs inhibited dietary behaviors of rats. Histological analysis indicated that PS20, PS200, and A-PS50 thinned out nasal mucosa. Immunohistochemical analysis revealed that exposure to PS20, PS200, and A-PS50 enhanced expression of transient receptor potential cation channel subfamily M (melastatin) member 8 (TRPM8). Systemic effects including hepatocyte cytoplasmic vacuolation and renal tubule dilatation were observed. The results suggested that nasal inhalation of MNPs may disturb energy metabolism and damage upper respiratory tract, liver, and kidneys.

Carbon nanostructures: a comprehensive review of potential applications and toxic effects

There is no doubt that nanotechnology has revolutionized our life since the 1970s when it was first introduced. Nanomaterials have helped us to improve the current products and services we use. Among the different types of nanomaterials, the application of carbon-based nanomaterials in every aspect of our lives has rapidly grown over recent decades. This review discusses recent advances of those applications in distinct categories, including medical, industrial, and environmental applications. The first main section introduces nanomaterials, especially carbon-based nanomaterials. In the first section, we discussed medical applications, including medical biosensors, drug and gene delivery, cell and tissue labeling and imaging, tissue engineering, and the fight against bacterial and fungal infections. The next section discusses industrial applications, including agriculture, plastic, electronic, energy, and food industries. In addition, the environmental applications, including detection of air and water pollutions and removal of environmental pollutants, were vastly reviewed in the last section. In the conclusion section, we discussed challenges and future perspectives.

Protective Effects of Zingiberis Carbonisata-Based Carbon Dots on Diabetic Liver Injury in Mice

To explain the active components of ZRC-CDs from the perspective of nanomaterials and investigate the potential mechanism for the treatment of diabetic liver injury, the structure, electron transfer properties, and elemental composition of ZRC-CDs were characterized. The protective effects of ZRC-CDs on the diabetic liver injury were demonstrated using the Alloxan-induced diabetic model. The ZRC-CDs are spherical, with a diameter ranging from 1.0–4.5 nm and a yield of 0.56%. The results showed that ZRC-CDs decreased the levels of blood glucose in diabetic mice and had a mitigating effect on elevated ALT and AST. More studies found that ZRC-CDs were able to decrease the levels of inflammatory cytokines and suppress the protein expression in related signaling pathways.

Biodegradable iron oxide nanoparticles for intraoperative parathyroid gland imaging in thyroidectomy

Parathyroid gland (PG) injury is the most common complication of thyroidectomy owing to the lack of approaches for surgeons to effectively distinguish PGs from surrounding thyroid glands (TGs) in the operation room. Herein, we report the development of biodegradable iron oxide nanoparticles (IONPs) as a promising contrast agent candidate for intraoperative PG visualization. We elucidated that locally administrated dark-colored IONPs readily diffuse in TGs but cannot infiltrate tissue-dense PGs, yielding a distinguishable contrast enhancement between PGs and TGs by naked eye observation. We performed unbiased and quantitative in vivo screenings to optimize particle size and concentration of IONPs for PG/TG contrast enhancement. Moreover, in vivo applications of IONPs via the local administration route demonstrate no adverse toxicities and can be biodegraded in the thyroid microenvironment within 3 months. To our knowledge, these promising findings provide the first in vivo evidence that IONPs can serve as a safe, biodegradable, and effective contrast agent candidate for improving PG visualization in thyroidectomy.

Endohedral Gd-Containing Fullerenol: Toxicity, Antioxidant Activity, and Regulation of Reactive Oxygen Species in Cellular and Enzymatic Systems

The Gd-containing metallofullerene derivatives are perspective magnetic resonance imaging contrast agents. We studied the bioeffects of a water-soluble fullerene derivative, gadolinium-endohedral fullerenol, with 40−42 oxygen groups (Gd@Fln). Bioluminescent cellular and enzymatic assays were applied to monitor toxicity and antioxidant activity of Gd@Fln in model solutions; bioluminescence was applied as a signaling physiological parameter. The Gd@Fln inhibited bioluminescence at high concentrations (>2·10−1 gL−1), revealing lower toxicity as compared to the previously studied fullerenols. Efficient activation of bioluminescence (up to almost 100%) and consumption of reactive oxygen species (ROS) in bacterial suspension were observed under low-concentration exposure to Gd@Fln (10−3−2·10−1 gL−1). Antioxidant capability of Gd@Fln was studied under conditions of model oxidative stress (i.e., solutions of model organic and inorganic oxidizers); antioxidant coefficients of Gd@Fln were determined at different concentrations and times of exposure. Contents of ROS were evaluated and correlations with toxicity/antioxidant coefficients were determined. The bioeffects of Gd@Fln were explained by hydrophobic interactions, electron affinity, and disturbing of ROS balance in the bioluminescence systems. The results contribute to understanding the molecular mechanism of “hormetic” cellular responses. Advantages of the bioluminescence assays to compare bioeffects of fullerenols based on their structural characteristics were demonstrated.

Graphene oxide links alterations of anti-viral signaling pathways with lipid metabolism via suppressing TLR3 in vascular smooth muscle cells

Vascular smooth muscle cells (VSMCs), the main cells constructing blood vessels, are important in the regulation of the pathophysiology of vascular systems; however, relatively few studies have investigated the influence of nanomaterials (NMs) on VSMCs.

Influences of Unmodified and Carboxylated Carbon Nanotubes on Lipid Profiles in THP-1 Macrophages: A Lipidomics Study

Since the possible roles of surface modifications in determining multi-walled carbon nanotube (MWCNT)-promoted endoplasmic reticulum (ER) stress-mediated lipid-laden macrophage foam cell formation are still in debate, we compared unmodified and carboxylated MWCNT-induced cytotoxicity, lipid profile changes, and expression of ER stress genes in THP-1 macrophages. Particularly, we focused on lipid profile changes by using lipidomics approaches. We found that unmodified and carboxylated MWCNTs significantly decreased cellular viability and appeared to damage the cellular membrane to a similar extent. Likewise, the results from Oil Red O staining showed that both types of MWCNTs slightly but significantly induced lipid accumulation. In keeping with Oil Red O staining results, lipidomics data showed that both types of MWCNTs up-regulated most of the lipid classes. Interestingly, almost all lipid classes were relatively higher in carboxylated MWCNT-exposed THP-1 macrophages compared with unmodified MWCNT-exposed cells, indicating that carboxylated MWCNTs more effectively changed lipid profiles. But in contrast to our expectation, none of the MWCNTs significantly induced the expression of ER stress genes. Even, compared with carboxylated MWCNTs, unmodified MWCNTs induced higher expression of lipid genes, including macrophage scavenger receptor 1 and fatty acid synthase. Combined, our results suggested that even though carboxylation did not significantly affect MWCNT-induced lipid accumulation, carboxylated MWCNTs were more potent to alter lipid profiles in THP-1 macrophages, indicating the need to use omics techniques to understand the exact nanotoxicological effects of MWCNTs. However, the differential effects of unmodified and carboxylated MWCNTs on lipid profiles might not be related with the induction of ER stress.

Inorganic Materials and Metal-Organic Frameworks: Editorial Announcement

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In Vitro and In Vivo Biocompatibility of Boron/Nitrogen Co-Doped Carbon Nano-Onions

Boron/nitrogen, co-doped, carbon nano-onions (BN-CNOs) have recently shown great promise as catalysts for the oxygen reduction reaction, due to the improved electronic properties imparted by the dopant atoms; however, the interactions of BN-CNOs with biological systems have not yet been explored. In this study, we examined the toxicological profiles of BN-CNOs and oxidized BN-CNOs (oxi-BN-CNOs) in vitro in both healthy and cancer cell lines, as well as on the embryonic stages of zebrafish (Danio rerio) in vivo. The cell viabilities of both cell lines cells were not affected after treatment with different concentrations of both doped CNO derivatives. On the other hand, the analysis of BN-CNOs and oxidized BN-CNO interactions with zebrafish embryos did not report any kind of perturbations, in agreement with the in vitro results. Our results show that both doped CNO derivatives possess a high biocompatibility and biosafety in cells and more complex systems.

Toxicity and Antioxidant Activity of Fullerenol C60,70 with Low Number of Oxygen Substituents

Fullerene is a nanosized carbon structure with potential drug delivery applications. We studied the bioeffects of a water-soluble fullerene derivative, fullerenol, with 10-12 oxygen groups (F10-12); its structure was characterized by IR and XPS spectroscopy. A bioluminescent enzyme system was used to study toxic and antioxidant effects of F10-12 at the enzymatic level. Antioxidant characteristics of F10-12 were revealed in model solutions of organic and inorganic oxidizers. Low-concentration activation of bioluminescence was validated statistically in oxidizer solutions. Toxic and antioxidant characteristics of F10-12 were compared to those of homologous fullerenols with a higher number of oxygen groups:F24-28 and F40-42. No simple dependency was found between the toxic/antioxidant characteristics and the number of oxygen groups on the fullerene’s carbon cage. Lower toxicity and higher antioxidant activity of F24-28 were identified and presumptively attributed to its higher solubility. An active role of reactive oxygen species (ROS) in the bioeffects of F10-12 was demonstrated. Correlations between toxic/antioxidant characteristics of F10-12 and ROS content were evaluated. Toxic and antioxidant effects were related to the decrease in ROS content in the enzyme solutions. Our results reveal a complexity of ROS effects in the enzymatic assay system.

Green Phellodendri Chinensis Cortex-based carbon dots for ameliorating imiquimod-induced psoriasis-like inflammation in mice

Background

Carbon dots (CDs) with multifaceted advantages have provided hope for development brand-new nanodrug for treating thorny diseases. This study developed a green and simple calcination method to prepare novel CDs as promising drug for psoriasis treatment. The as-prepared CDs using Phellodendri Chinensis Cortex (PCC) as sole precursor were characterized by a series of methods, mainly including electron microscopy, optical technology and X-ray photoelectron spectroscopy (XPS).

Results

Results displayed that fluorescence (Quantum yield = 5.63%) and nontoxic PCC-based CDs (PCC-CDs) with abundant chemical groups exhibited solubility and tiny sizes at average of (1.93 ± 0.53) nm, which may be beneficial for its inherent biological activity. Moreover, by using the typical imiquimod (IMQ)-induced psoriasis-like skin mouse model, we firstly demonstrated the pronounced anti-psoriasis activity of as-prepared PCC-CDs on ameliorating the appearance, psoriasis area and severity index (PASI) scores as well as histopathological morphology of both back skin tissues and right ears in IMQ-induced mouse. Further potential mechanisms behind the anti-psoriasis activities may be related to suppress M1 polarization and relatively promote M2 polarization of macrophage both in vitro and in vivo.

Conclusion

These results suggested that PCC-CDs have potential to be an anti-psoriasis candidate for clinical applications to treat psoriasis, which not only provided an evidence for further broadening the biological application of CDs, but also provided a potential hope for application nanodrugs to treat thorny diseases.

Graphic Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-00847-y.

Mechanism of action and cellular responses of HEK293 cells on challenge with zwitterionic carbon dots

Carbon, an extremely versatile element has great demand in the field of nanoscience. Carbon-based nanostructures are exponentially increased due to its wide range of applications in biotechnological and environmental approaches; hence, its safety assessment is of greater concern. In the present study, high quantum yielding zwitterionic carbon dots were synthesized, characterized and its safety assessment at different concentration ranges (50-1600 μgmL^-1) on HEK 293 cells was carried out. Cellular, mitochondrial, lysosomal integrity and ROS generation were assessed using specific fluorochromes.The key cellular event apoptosis was assessed by annexinpropidium iodide staining using imaging flow cytometry. Moreover, the mRNA levels of the apoptotic genes were determined by real-time PCR. The results revealed that the cell viability assays (MTT, NR) and mitochondrial membrane potential were altered on exposure to a higher concentration of zwitterionic CDs for 24 h. Also, annexinpropidiumiodidestaining exhibited an increased percentage of apoptotic cells upon exposure to zwitterionic CDs at higher concentrations. Further, apoptosis was confirmed by significantlyincreased expression of pro-apoptotic gene (Bax) together with decreased expression of Bcl-2/Bax ratio. Collectively, this study suggests that zwitterionic CDs induce apoptosis in HEK 293 at higher concentration and the safe range for its intended application is found to be 50-200 μg/mL.

Structure-directed formation of the dative/covalent bonds in complexes with C70piperidine

The combined experimental-computational study has been performed to investigate the complexes formed between C70 carbon allotrope and piperidine. The results of FT-IR, H-NMR, and C-NMR measurements, together with the calculations based on the DFT approach and molecular dynamics simulations, prove the existence of dative/covalent bonding in C70piperidine complexes. The dative bond forms not only at the region of five- and six-membered rings, observed previously with C60, but also at the region formed of six-membered rings. The structure, i.e., nonplanarity, explains the observed dative bond formation. New findings on the character of interaction of secondary amines with C70 bring new aspects for the rational design of modified fullerenes and their applications in electrocatalysis, spintronics, and energy storage.

Recent Advances in Methods for the Recovery of Carbon Nanominerals and Polyaromatic Hydrocarbons from Coal Fly Ash and Their Emerging Applications

Coal fly ash is found to be one of the key pollutants worldwide due to its toxic heavy metal content. However, due to advancements in technology, coal fly ash has gained importance in various emerging fields. They are rich sources of carbonaceous particles which remain unburnt during burning of various coals in thermal power plants (TPPs). Various carbonaceous nanoparticles in the form of fullerenes, soot, and carbon nanotubes could be recovered from coal fly ash by applying trending techniques. Moreover, coal fly ash is comprised of rich sources of organic carbons such as polycyclic and polyaromatic hydrocarbons that are used in various industries for the development of carbon-derived value-added materials and nanocomposites. Here, we focus on all the types of carbon nanominerals from coal fly ash with the latest techniques applied. Moreover, we also emphasize the recovery of organic carbons in polyaromatic (PAHs) and polycyclic hydrocarbons (PCHs) from coal fly ash (CFA). Finally, we try to elucidate the latest applications of such carbon particle in the industry.

New Nanostructured Carbon Coating Inhibits Bacterial Growth, but Does Not Influence on Animal Cells

An electrospark technology has been developed for obtaining a colloidal solution containing nanosized amorphous carbon. The advantages of the technology are its low cost and high performance. The colloidal solution of nanosized carbon is highly stable. The coatings on its basis are nanostructured. They are characterized by high adhesion and hydrophobicity. It was found that the propagation of microorganisms on nanosized carbon coatings is significantly hindered. At the same time, eukaryotic animal cells grow and develop on nanosized carbon coatings, as well as on the nitinol medical alloy. The use of a colloidal solution as available, cheap and non-toxic nanomaterial for the creation of antibacterial coatings to prevent biofilm formation seems to be very promising for modern medicine, pharmaceutical and food industries.