A facile, environment-friendly, versatile and reproducible approach to the successful oxidation of fullerenes (oxC₆₀) and the formation of highly hydrophilic fullerene derivatives is introduced. This synthesis relies on the widely known Staudenmaier’s method for the oxidation of graphite, to produce both epoxy and hydroxy groups on the surface of fullerenes (C₆₀) and thereby improve the solubility of the fullerene in polar solvents (e.g. water). The presence of epoxy groups allows for further functionalization via nucleophilic substitution reactions to generate new fullerene derivatives, which can potentially lead to a wealth of applications in the areas of medicine, biology, and composite materials. In order to justify the potential of oxidized C₆₀ derivatives for bio-applications, we investigated their cytotoxicity in vitro as well as their utilization as support in biocatalysis applications, taking the immobilization of laccase for the decolorization of synthetic industrial dyes as a trial case.

CO₂ hydrogenation toward methane, a reaction of high environmental and sustainable energy importance, was investigated at 200–600 °C and H₂/CO₂ = 4/1, over Rh nanoparticles dispersed on supports with different oxygen storage capacity characteristics (γ-Al₂O₃, alumina-ceria-zirconia, and ceria-zirconia). The effects of the support OSC and Rh particle size on reaction behavior under both integral and differential conditions were investigated, to elucidate the combined role of these crucial catalyst design parameters on methanation efficiency. A volcano-type variation of methanation turnover frequency was found in respect to support OSC; Rh/ACZ, with intermediate OSC, was the optimal catalyst. The structure sensitivity of the reaction was found to be a combined function of support OSC and Rh particle size: For Rh/γ-Al₂O₃ (lack of OSC) methanation was strongly favored on small particles—the opposite for Rh/CZ (high OSC). The findings are promising for rational design and optimization of CO₂ methanation catalysts by tailoring the aforementioned characteristics.

Much of the research effort concerning layered materials is directed toward their use as building blocks for the development of hybrid nanostructures with well-defined dimensions and behavior. Here, we report the fabrication through layer-by-layer deposition and intercalation chemistry of a new type of clay-based hybrid film, where functionalized carbon nanotubes are sandwiched between nanometer-sized smectite clay platelets. Single-walled carbon nanotubes (SWCNTs) were covalently functionalized in a single step with phenol groups, via 1,3-dipolar cycloaddition, to allow for stable dispersion in polar solvents. For the production of hybrid thin films, a bottom-up approach combining self-assembly with Langmuir–Schaefer deposition was applied. Smectite clay nanoplatelets act as a structure-directing interface and reaction media for grafting functionalized carbon nanotubes in a bidimensional array, allowing for a controllable layer-by-layer growth at a nanoscale. Hybrid clay/SWCNT multilayer films deposited on various substrates were characterized by X-ray reflectivity, Raman, and X-ray photoelectron spectroscopies, as well as atomic force microscopy.

In this work, we demonstrated the ability of the cyanobacterium Pseudanabaena/Limnothrix sp. to produce ultra-small silver nanoparticlesin the forms of metallic silver (Ag⁰) and silver oxides (Ag_xO_y) via a facile green synthetic process. The biological compounds in the cyanobacterial cellular extract acted both as reducing agents for silver ions and functional stabilizing agents for the silver nanoparticles. Furthermore, the antibacterical activity of the as-synthesized nanoparticles against Gram-negative Escherichia coli and Gram-positive Corynebacterium glutamicum bacterial cells was evaluated. The experimental results revealed a remarkable bactericidal activity of the nanoparticles that was both time-dependent and dose-dependent. In addition to their excellent bactericidal properties, the developed nanoparticles can be used as nanosupports in various environmental, biological, and medical applications.

Background: Graphene Oxide (GO) has shown great potential in biomedical applications for cancer therapeutics. The biosafety and stability issues of GO in biological media have been addressed by functionalization with polyethylene glycol (PEG). Methods: In this work, carboxylated, nanosized GO (nCGO) was evaluated as a potential carrier of paclitaxel (PCT). The effect of PEG characteristics on particle size and surface charge, colloidal stability, drug, and release, and the hemolytic potential of nCGO, was investigated. Optimum PEG-nCGO/PCT formulations based on the above properties were evaluated for their anticancer activity (cytotoxicity and apoptosis induction) in the A549 lung cancer cell line. Results: An increase in the length of linear PEG chains and the use of branched (4-arm) instead of linear PEG resulted in a decrease in hydrodynamic diameter and an increase in ζ potential of the pegylated nCGO particles. Pegylated nCGO exhibited high colloidal stability in phosphate-buffered saline and in cell culture media and low hemolytic effect, even at a relatively high concentration of 1 mg/mL. The molecular weight of PEG and branching adversely affected PCT loading. An increased rate of PCT release at an acidic pH of 6.0 compared to the physiological pH of 7.4 was observed with all types of pegylated nCGO/PCT. Pegylated nCGO exhibited lower cytotoxicity and apoptotic activity than non-pegylated nCGO. Cellular uptake of pegylated nCGO increased with incubation time with cells leading to increased cytotoxicity of PEG-nCGO/PCT with incubation time, which became higher than that of free PCT at 24 and 48 h of incubation. Conclusions: The increased biocompatibility of the pegylated nCGO and the enhanced anticancer activity of PEG-nCGO/PCT compared to free PCT are desirable properties with regard to the potential clinical application of PEG-nCGO/PCT as an anticancer nanomedicine.

Targeting cancer cells without affecting normal cells poses a particular challenge. Nevertheless, the utilization of innovative nanomaterials in targeted cancer therapy has witnessed significant growth in recent years. In this study, we examined two layered carbon nanomaterials, graphene and carbon nanodiscs (CNDs), both of which possess extraordinary physicochemical and structural properties alongside their nano-scale dimensions, and explored their potential as nanocarriers for quercetin, a bioactive flavonoid known for its potent anticancer properties. Within both graphitic allotropes, oxidation results in heightened hydrophilicity and the incorporation of oxygen functionalities. These factors are of great significance for drug delivery purposes. The successful oxidation and interaction of quercetin with both graphene (GO) and CNDs (oxCNDs) have been confirmed through a range of characterization techniques, including FTIR, Raman, and XPS spectroscopy, as well as XRD and AFM. In vitro anticancer tests were conducted on both normal (NIH/3T3) and glioblastoma (U87) cells. The results revealed that the bonding of quercetin with GO and oxCNDs enhances its cytotoxic effect on cancer cells. GO-Quercetin and oxCNDs-Quercetin induced G0/G1 cell cycle arrest in U87 cells, whereas oxCNDs caused G2/M arrest, indicating a distinct mode of action. In long-term survival studies, cancer cells exhibited significantly lower viability than normal cells at all corresponding doses of GO-Quercetin and oxCNDs-Quercetin. This work leads us to conclude that the conjugation of quercetin to GO and oxCNDs shows promising potential for targeted anticancer activity. However, further research at the molecular level is necessary to substantiate our preliminary findings.