In Vitro Mineralization Study of Chitosan/Carbon Nanotubes Scaffolds: Effect of Mineralization Cycles

Carbon nanotubes (CNTs) and carbon nanofibers (CNFs) are erroneously considered as singular material entities. Instead, they should be regarded as a heterogeneous class of materials bearing different properties eliciting peculiar biological outcomes both in vitro and in vivo. Given the pace at which the industrial production of CNTs/CNFs is increasing, it is becoming of utmost importance to acquire comprehensive knowledge regarding their biological activity and their hazardous effects in humans. Animal studies carried out by inhalation showed that some CNTs/CNFs species can cause deleterious effects such as inflammation and lung tissue remodeling. Their physico-chemical properties, biological behavior and biopersistence make them similar to asbestos fibers. Human studies suggest some mild effects in workers handling CNT/CNF. However, owing to their cross-sectional design, researchers have been as yet unable to firmly demonstrate a causal relationship between such an exposure and the observed effects. Estimation of acceptable exposure levels should warrant a proper risk management. The aim of this review is to challenge the conception of CNTs/CNFs as a single, unified material entity and prompt the establishment of standardized hazard and exposure assessment methodologies able to properly feeding risk assessment and management frameworks.

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New Mechanistic Insights on Carbon Nanotubes’ Nanotoxicity Using Isolated Submitochondrial Particles, Molecular Docking, and Nano-QSTR Approaches

Biology ◽

10.3390/biology10030171 ◽

2021 ◽

Vol 10 (3) ◽

pp. 171

Author(s):

Michael González-Durruthy ◽

Riccardo Concu ◽

Juan M. Ruso ◽

M. Natália D. S. Cordeiro

Keyword(s):

Carbon Nanotubes ◽

Network Models ◽

Single Walled Carbon Nanotubes ◽

Docking Studies ◽

Fractal Surface ◽

Submitochondrial Particles ◽

Elastic Network ◽

Elastic Network Models ◽

Walled Carbon Nanotubes

Single-walled carbon nanotubes can induce mitochondrial F0F1-ATPase nanotoxicity through inhibition. To completely characterize the mechanistic effect triggering the toxicity, we have developed a new approach based on the combination of experimental and computational study, since the use of only one or few techniques may not fully describe the phenomena. To this end, the in vitro inhibition responses in submitochondrial particles (SMP) was combined with docking, elastic network models, fractal surface analysis, and Nano-QSTR models. In vitro studies suggest that inhibition responses in SMP of F0F1-ATPase enzyme were strongly dependent on the concentration assay (from 3 to 5 µg/mL) for both pristine and COOH single-walled carbon nanotubes types (SWCNT). Besides, both SWCNTs show an interaction inhibition pattern mimicking the oligomycin A (the specific mitochondria F0F1-ATPase inhibitor blocking the c-ring F0 subunit). Performed docking studies denote the best crystallography binding pose obtained for the docking complexes based on the free energy of binding (FEB) fit well with the in vitro evidence from the thermodynamics point of view, following an affinity order such as: FEB (oligomycin A/F0-ATPase complex) = −9.8 kcal/mol > FEB (SWCNT-COOH/F0-ATPase complex) = −6.8 kcal/mol ~ FEB (SWCNT-pristine complex) = −5.9 kcal/mol, with predominance of van der Waals hydrophobic nano-interactions with key F0-ATPase binding site residues (Phe 55 and Phe 64). Elastic network models and fractal surface analysis were performed to study conformational perturbations induced by SWCNT. Our results suggest that interaction may be triggering abnormal allosteric responses and signals propagation in the inter-residue network, which could affect the substrate recognition ligand geometrical specificity of the F0F1-ATPase enzyme in order (SWCNT-pristine > SWCNT-COOH). In addition, Nano-QSTR models have been developed to predict toxicity induced by both SWCNTs, using results of in vitro and docking studies. Results show that this method may be used for the fast prediction of the nanotoxicity induced by SWCNT, avoiding time- and money-consuming techniques. Overall, the obtained results may open new avenues toward to the better understanding and prediction of new nanotoxicity mechanisms, rational drug design-based nanotechnology, and potential biomedical application in precision nanomedicine.

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Femtosecond pulsed laser microscopy: a new tool to assess the in vitro delivered dose of carbon nanotubes in cell culture experiments

Particle and Fibre Toxicology ◽

10.1186/s12989-021-00402-5 ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Dominique Lison ◽

Saloua Ibouraadaten ◽

Sybille van den Brule ◽

Milica Todea ◽

Adriana Vulpoi ◽

...

Keyword(s):

Carbon Nanotubes ◽

Cell Culture ◽

Pulsed Laser ◽

Lung Fibroblasts ◽

Laser Microscopy ◽

Cell Responses ◽

The Impact ◽

Delivered Dose ◽

Femtosecond Pulsed Laser

Abstract Background In vitro models are widely used in nanotoxicology. In these assays, a careful documentation of the fraction of nanomaterials that reaches the cells, i.e. the in vitro delivered dose, is a critical element for the interpretation of the data. The in vitro delivered dose can be measured by quantifying the amount of material in contact with the cells, or can be estimated by applying particokinetic models. For carbon nanotubes (CNTs), the determination of the in vitro delivered dose is not evident because their quantification in biological matrices is difficult, and particokinetic models are not adapted to high aspect ratio materials. Here, we applied a rapid and direct approach, based on femtosecond pulsed laser microscopy (FPLM), to assess the in vitro delivered dose of multi-walled CNTs (MWCNTs). Methods and results We incubated mouse lung fibroblasts (MLg) and differentiated human monocytic cells (THP-1) in 96-well plates for 24 h with a set of different MWCNTs. The cytotoxic response to the MWCNTs was evaluated using the WST-1 assay in both cell lines, and the pro-inflammatory response was determined by measuring the release of IL-1β by THP-1 cells. Contrasting cell responses were observed across the MWCNTs. The sedimentation rate of the different MWCNTs was assessed by monitoring turbidity decay with time in cell culture medium. These turbidity measurements revealed some differences among the MWCNT samples which, however, did not parallel the contrasting cell responses. FPLM measurements in cell culture wells revealed that the in vitro delivered MWCNT dose did not parallel sedimentation data, and suggested that cultured cells contributed to set up the delivered dose. The FPLM data allowed, for each MWCNT sample, an adjustment of the measured cytotoxicity and IL-1β responses to the delivered doses. This adjusted in vitro activity led to another toxicity ranking of the MWCNT samples as compared to the unadjusted activities. In macrophages, this adjusted ranking was consistent with existing knowledge on the impact of surface MWCNT functionalization on cytotoxicity, and might better reflect the intrinsic activity of the MWCNT samples. Conclusion The present study further highlights the need to estimate the in vitro delivered dose in cell culture experiments with nanomaterials. The FPLM measurement of the in vitro delivered dose of MWCNTs can enrich experimental results, and may refine our understanding of their interactions with cells.

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Profiling of Sub-Lethal in Vitro Effects of Multi-Walled Carbon Nanotubes Reveals Changes in Chemokines and Chemokine Receptors

Nanomaterials ◽

10.3390/nano11040883 ◽

2021 ◽

Vol 11 (4) ◽

pp. 883 ◽

Cited By ~ 1

Author(s):

Sandeep Keshavan ◽

Fernando Torres Andón ◽

Audrey Gallud ◽

Wei Chen ◽

Knut Reinert ◽

...

Keyword(s):

Carbon Nanotubes ◽

Chemokine Receptors ◽

Research Centre ◽

Target Cells ◽

Joint Research ◽

Chemokine Signaling ◽

Multi Walled Carbon Nanotubes ◽

Downstream Analysis ◽

Walled Carbon Nanotubes

Engineered nanomaterials are potentially very useful for a variety of applications, but studies are needed to ascertain whether these materials pose a risk to human health. Here, we studied three benchmark nanomaterials (Ag nanoparticles, TiO2 nanoparticles, and multi-walled carbon nanotubes, MWCNTs) procured from the nanomaterial repository at the Joint Research Centre of the European Commission. Having established a sub-lethal concentration of these materials using two human cell lines representative of the immune system and the lungs, respectively, we performed RNA sequencing of the macrophage-like cell line after exposure for 6, 12, and 24 h. Downstream analysis of the transcriptomics data revealed significant effects on chemokine signaling pathways. CCR2 was identified as the most significantly upregulated gene in MWCNT-exposed cells. Using multiplex assays to evaluate cytokine and chemokine secretion, we could show significant effects of MWCNTs on several chemokines, including CCL2, a ligand of CCR2. The results demonstrate the importance of evaluating sub-lethal concentrations of nanomaterials in relevant target cells.

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Synthesis of Poly(methacrylic acid-co-butyl acrylate) Grafted onto Functionalized Carbon Nanotube Nanocomposites for Drug Delivery

Polymers ◽

10.3390/polym13040533 ◽

2021 ◽

Vol 13 (4) ◽

pp. 533 ◽

Cited By ~ 1

Author(s):

Josué A. Torres-Ávalos ◽

Leonardo R. Cajero-Zul ◽

Milton Vázquez-Lepe ◽

Fernando A. López-Dellamary ◽

Antonio Martínez-Richa ◽

...

Keyword(s):

Carbon Nanotubes ◽

Drug Delivery ◽

Methacrylic Acid ◽

Butyl Acrylate ◽

Chemical Vapor ◽

Vis Spectroscopy ◽

Ir And Raman Spectroscopies ◽

Ft Ir

Design of a smart drug delivery system is a topic of current interest. Under this perspective, polymer nanocomposites (PNs) of butyl acrylate (BA), methacrylic acid (MAA), and functionalized carbon nanotubes (CNTsf) were synthesized by in situ emulsion polymerization (IEP). Carbon nanotubes were synthesized by chemical vapor deposition (CVD) and purified with steam. Purified CNTs were analyzed by FE-SEM and HR-TEM. CNTsf contain acyl chloride groups attached to their surface. Purified and functionalized CNTs were studied by FT-IR and Raman spectroscopies. The synthesized nanocomposites were studied by XPS, 13C-NMR, and DSC. Anhydride groups link CNTsf to MAA–BA polymeric chains. The potentiality of the prepared nanocomposites, and of their pure polymer matrices to deliver hydrocortisone, was evaluated in vitro by UV–VIS spectroscopy. The relationship between the chemical structure of the synthesized nanocomposites, or their pure polymeric matrices, and their ability to release hydrocortisone was studied by FT-IR spectroscopy. The hydrocortisone release profile of some of the studied nanocomposites is driven by a change in the inter-associated to self-associated hydrogen bonds balance. The CNTsf used to prepare the studied nanocomposites act as hydrocortisone reservoirs.

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Biocompatibility Characteristics of Titanium Coated with Multi Walled Carbon Nanotubes—Hydroxyapatite Nanocomposites

Materials ◽

10.3390/ma12020224 ◽

2019 ◽

Vol 12 (2) ◽

pp. 224 ◽

Cited By ~ 5

Author(s):

Jung-Eun Park ◽

Yong-Seok Jang ◽

Tae-Sung Bae ◽

Min-Ho Lee

Keyword(s):

Electron Microscopy ◽

Carbon Nanotubes ◽

Sol Gel ◽

Pure Titanium ◽

Cell Proliferation And Differentiation ◽

Transmission Electron ◽

Proliferation And Differentiation ◽

Multi Walled Carbon Nanotubes ◽

Walled Carbon Nanotubes

Multi walled carbon nanotubes-hydroxyapatite (MWCNTs-HA) with various contents of MWCNTs was synthesized using the sol-gel method. MWCNTs-HA composites were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). HA particles were generated on the surface of MWCNT. Produced MWCNTs-HA nanocomposites were coated on pure titanium (PT). Characteristic of the titanium coated MWCNTs-HA was evaluated by field-emission scanning electron microscopy (FE-SEM) and XRD. The results show that the titanium surface was covered with MWCNTs-HA nanoparticles and MWCNTs help form the crystalized hydroxyapatite. Furthermore, the MWCNTs-HA coated titanium was investigated for in vitro cellular responses. Cell proliferation and differentiation were improved on the surface of MWCNT-HA coated titanium.

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In Vitro Mineralization and Cell Adhesion on Surface Modified Poly (2 - hydroxy ethyl methacrylate-co-methyl methacrylate

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.309-311.493 ◽

2006 ◽

Vol 309-311 ◽

pp. 493-496 ◽

Cited By ~ 3

Author(s):

G.S. Sailaja ◽

T.V. Kumari ◽

Yoshiyuki Yokogawa ◽

H.K. Varma

Keyword(s):

Cell Adhesion ◽

Calcium Phosphate ◽

Methyl Methacrylate ◽

Radical Copolymerization ◽

Sem Analysis ◽

Free Radical Copolymerization ◽

In Vitro Mineralization ◽

Atr Spectroscopy ◽

Surface Modified

Poly(2-hydroxyethyl methacrylate-co- methyl methacrylate) HM, was synthesized by free radical copolymerization, cross-linked with ethylene glycol dimethacrylate and phosphorylated. The phosphate coupling was ensured by ATR spectroscopy. The in vitro mineralization ability of the phosphorylated HM (designated as PHM) was investigated by studying the nucleation and growth of calcium phosphate on its surface by immersing in simulated body fluid (SBF) solution. The coating morphology was studied by SEM and the Ca/P ratio of the coating by EDX analysis. The cell adhesion behaviour of PHM was studied by seeding Human osteosarcoma (HOS) cells for one week followed by SEM analysis along with HM as control. It was observed that HOS cells exhibited biomineralization of calcium phosphate on the surface of HM as well as on PHM with a significantly higher amount on the surface of PHM as observed by von kossa staining method. The results show that PHM is capable of in vitro mineralization under simulated physiological condition, promotes cell adhesion by providing an excellent cell friendly surface and it exhibits biomineralization of calcium phosphate in presence of HOS cells.

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