Toxic Effect of Fullerene and Its Derivatives upon the Transmembrane β2-Adrenergic Receptors

Fullertubes inhibit mycobacterial viability and prevent biofilm formation by disrupting the cell wall

Mycobacterium tuberculosis and nontuberculous mycobacteria such as Mycobacterium abscessus cause diseases that are becoming increasingly difficult to treat due to emerging antibiotic resistance. The development of new antimicrobial molecules is vital for combating these pathogens. Carbon nanomaterials (CNMs) are a class of carbon-containing nanoparticles with promising antimicrobial effects. Fullertubes (C90 ) are novel carbon allotropes with a structure unique among CNMs. The effects of fullertubes on any living cell have not been studied. In this study, we demonstrate that pristine fullertube dispersions show antimicrobial effects on Mycobacterium smegmatis and M. abscessus. Using scanning electron microscopy, light microscopy, and molecular probes, we investigated the effects of these CNMs on mycobacterial cell viability, cellular integrity, and biofilm formation. C90 fullertubes at 1 µM inhibited mycobacterial viability by 97%. Scanning electron microscopy revealed that the cell wall structure of M. smegmatis and M. abscessus was severely damaged within 24 h of exposure to fullertubes. Additionally, exposure to fullertubes nearly abrogated the acid-fast staining property of M. smegmatis. Using SYTO-9 and propidium iodide, we show that exposure to the novel fullertubes compromises the integrity of the mycobacterial cell. We also show that the permeability of the mycobacterial cell wall was increased after exposure to fullertubes from our assays utilizing the molecular probe dichlorofluorescein and ethidium bromide transport. C90 fullertubes at 0.37 µM and C60 fullerenes at 0.56 µM inhibited pellicle biofilm formation by 70% and 90%, respectively. This is the first report on the antimycobacterial activities of fullertubes and fullerenes.

Effects of Endohedral Gd-Containing Fullerenols with a Different Number of Oxygen Substituents on Bacterial Bioluminescence

Gadolinium (Gd)-containing fullerenols are perspective agents for magnetic resonance imaging and cancer research. They combine the unique paramagnetic properties of Gd with solubility in water, low toxicity and antiradical activity of fullerenols. We compared the bioeffects of two Gd-containing fullerenols with a different number of oxygen groups-20 and 42: Gd@C82O20H14 and Gd@C82O42H32. The bioluminescent bacteria-based assay was applied to monitor the toxicity of fullerenols, bioluminescence was applied as a signal physiological parameter, and bacterial enzyme-based assay was used to evaluate the fullerenol effects on enzymatic intracellular processes. Chemiluminescence luminol assay was applied to monitor the content of reactive oxygen species (ROS) in bacterial and enzymatic media. It was shown that Gd@C82O42H32 and Gd@C82O20H14 inhibited bacterial bioluminescence at >10-1 and >10-2 gL-1, respectively, revealing a lower toxicity of Gd@C82O42H32. Low-concentration (10-3-10-1 gL-1) bacterial bioluminescence activation by Gd@C82O42H32 was observed, while this activation was not found under exposure to Gd@C82O20H14. Additional carboxyl groups in the structure of Gd@C82O42H32 were determined by infrared spectroscopy and confirmed by quantum chemical calculations. The groups were supposed to endow Gd@C82O42H32 with higher penetration ability through the cellular membrane, activation ability, lower toxicity, balancing of the ROS content in the bacterial suspensions, and lower aggregation in aqueous media.

Interactions between modified fullerenes and proteins in cancer nanotechnology

Fullerenes have numerous properties that fill the gap between small molecules and nanomaterials. Several types of chemical reaction allow their surface to be ornamented with functional groups designed to change them into 'ideal' nanodelivery systems. Improved stability, and bioavailability are important, but chemical modifications can render them practically soluble in water. 'Buckyball' fullerene scaffolds can interact with many biological targets and inhibit several proteins essential for tumorigeneses. Herein, we focus on the inhibitory properties of fullerene nanomaterials against essential proteins in cancer nanotechnology, as well as the use of dedicated proteins to improve the bioavailability of these promising nanomaterials.

Cytotoxicity of Carbon Nanotubes, Graphene, Fullerenes, and Dots

The cytotoxicity of carbon nanomaterials is a very important issue for microorganisms, animals, and humans. Here, we discuss the issues of cytotoxicity of carbon nanomaterials, carbon nanotubes, graphene, fullerene, and dots. Cytotoxicity issues, such as cell viability and drug release, are considered. The main part of the review is dedicated to important cell viability issues. They are presented for A549 human melanoma, E. coli, osteosarcoma, U2-OS, SAOS-2, MG63, U87, and U118 cell lines. Then, important drug release issues are discussed. Bioimaging results are shown here to illustrate the use of carbon derivatives as markers in any type of imaging used in vivo/in vitro. Finally, perspectives of the field are presented. The important issue is single-cell viability. It can allow a correlation of the functionality of organelles of single cells with the development of cancer. Such organelles are mitochondria, nuclei, vacuoles, and reticulum. It allows for finding biochemical evidence of cancer prevention in single cells. The development of investigation methods for single-cell level detection of viability stimulates the cytotoxicity investigative field. The development of single-cell microscopy is needed to improve the resolution and accuracy of investigations. The importance of cytotoxicity is drug release. It is important to control the amount of drug that is released. This is performed with pH, temperature, and electric stimulation. Further development of drug loading and bioimaging is important to decrease the cytotoxicity of carbon nanomaterials. We hope that this review is useful for researchers from all disciplines across the world.