Fluorinated Nanocarbons Cytotoxicity

Effect of Fluorographene Addition on Mechanical and Adhesive Properties of a New Core Build-Up Composite

This study aims to develop a restorative material having such mechanical and adhesive properties that it can be used both as a reconstruction material and as a luting cement. The experimental core build-up composite (CBC) was derived from a self-adhesive cement by the modification of its chemical formula, requiring the use of dedicated dentin and ceramic primers. The adhesive properties to zirconia and dentin were analyzed with a micro-Shear Bond Strength test (mSBS). The mechanical properties were analyzed by a flexural strength test. The results were compared with those obtained for other commercially available cements and core build-up materials, both before and after addition of 2 wt.% fluorographene. The CBC obtained average values in the mSBS of 49.7 ± 4.74 MPa for zirconia and 32.2 ± 4.9 MPa for dentin, as well as values of 110.9 ± 9.3 MPa for flexural strength and 6170.8 ± 703.2 MPa for Young's modulus. The addition of fluorographene, while increasing the Young's modulus of the core build-up composite by 10%, did not improve the adhesive capabilities of the primers and cement on either zirconia or dentin. The CBC showed adhesive and mechanical properties adequate both for a restoration material and a luting cement. The addition of 2 wt.% fluorographene was shown to interfere with the polymerization reaction of the material, suggesting the need for further studies.

Chemistry, properties, and applications of fluorographene

Fluorographene, formally a two-dimensional stoichiometric graphene derivative, attracted remarkable attention of the scientific community due to its extraordinary physical and chemical properties. We overview the strategies for the preparation of fluorinated graphene derivatives, based on top-down and bottom-up approaches. The physical and chemical properties of fluorographene, which is considered as one of the thinnest insulators with a wide electronic band gap, are presented. Special attention is paid to the rapidly developing chemistry of fluorographene, which was advanced in the last few years. The unusually high reactivity of fluorographene, which can be chemically considered perfluorinated hydrocarbon, enables facile and scalable access to a wide portfolio of graphene derivatives, such as graphene acid, cyanographene and allyl-graphene. Finally, we summarize the so far reported applications of fluorographene and fluorinated graphenes, spanning from sensing and bioimaging to separation, electronics and energy technologies.

Cellular proliferation and differentiation induced by single-layer molybdenum disulfide and mediation mechanisms of proteins via the Akt-mTOR-p70S6K signaling pathway

Single-layer molybdenum disulfide (SLMoS₂) is a novel kind of 2D nanosheet that has attracted great attention regarding its use in biosensors, drug delivery, tissue engineering, and therapy. However, our results demonstrated that SLMoS₂ accelerated proliferation and promoted myogenic differentiation and epithelial-mesenchymal transition (EMT) in human embryonic lung fibroblasts (HELFs). The abnormal proliferation and differentiation of HELFs contribute to idiopathic pulmonary fibrosis. Specifically, SLMoS₂ significantly stimulated the expression of myofibroblast- and mesenchymal-associated genes and proteins. The Akt-mTOR-p70S6K signaling pathway plays a critical role in the acceleration of proliferation and promotion of myogenic differentiation and EMT in HELFs induced by SLMoS₂. After cell uptake, SLMoS₂ was primarily located in the cytoplasm and the perinuclear region and activated Akt-dependent signaling due to the generation of reactive oxygen species (ROS). Moreover, bovine serum albumin (BSA) binding markedly inhibited the cellular uptake of SLMoS₂ and the production of intracellular ROS due to an increased thickness and reduced adhesion of HELFs. BSA binding also mitigated the SLMoS₂-activated phosphorylation of Akt-dependent signaling pathways. This study is the first to illustrate the induction of cellular proliferation and differentiation by SLMoS₂ and the related mediation by proteins through Akt-mTOR-p70S6K signaling pathway.

Fluorine Functionalized Graphene Quantum Dots as Inhibitor against hIAPP Amyloid Aggregation

Fibrillar deposits of the human islet amyloid polypeptide (hIAPP) are considered as a root of Type II diabetes mellitus. Fluorinated graphene quantum dots (FGQDs) are new carbon nanomaterials with unique physicochemical properties containing highly electronegative F atoms. Herein we report a single step synthesis method of FGQDs with an inhibitory effect on aggregation and cytotoxicity of hIAPP in vitro. Highly fluorescent and water dispersible FGQDs, less than 3 nm in size, were synthesized by the microwave-assisted hydrothermal method. Efficient inhibition capability of FGQDs to amyloid aggregation was demonstrated. The morphologies of hIAPP aggregates were observed to change from the entangled long fibrils to short thin fibrils and amorphous aggregates in the presence of FGQDs. In thioflavin T fluorescence analysis, inhibited aggregation with prolonged lag time and reduced fluorescence intensity at equilibrium were observed when hIAPP was incubated together with FGQDs. Circular dichroism spectrum results reveal that FGQDs could inhibit conformational transition of the peptide from native structure to β-sheets. FGQDs could also rescue the cytotoxicity of INS-1 cells induced by hIAPP in a dose dependent manner. This study could be beneficial for design and preparation of inhibitors for amyloids, which is important for prevention and treatment of amyloidosis.

Cytotoxicity of fluorographene

Fluorinated graphenes (F-G) might inevitably be released into the environment through disposal and wearing of future commercial products incorporated with F-G. Therefore, we determined their cytotoxicity in this study.