scholarly journals Characterization of Betulinic Acid-Multiwalled Carbon Nanotubes Modified with Hydrophilic Biopolymer for Improved Biocompatibility on NIH/3T3 Cell Line

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1362
Author(s):  
Julia Meihua Tan ◽  
Saifullah Bullo ◽  
Sharida Fakurazi ◽  
Mohd Zobir Hussein
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Betulinic Acid ◽  
Electrostatic Interactions ◽  
Aqueous Media ◽  
Mouse Fibroblast ◽  
Tween 20 ◽  
Multiwalled Carbon ◽  
Cell Viability Assay ◽  
Embryonic Mouse

The biocompatibility of carbon nanotubes (CNT) is fairly a challenging task for their applications in nanomedicine. Therefore, the objective of this research was to formulate four types of highly biocompatible betulinic acid-loaded biopolymer nanocomposites, namely chitosan-multiwalled carbon nanotubes (MWBA-CS), polyethylene glycol-multiwalled carbon nanotubes (MWBA-PG), Tween 20-multiwalled carbon nanotubes (MWBA-T2) and Tween 80-multiwalled carbon nanotubes (MWBA-T8). The physico-chemical properties of the modified nanocomposites were determined by Fourier transform infrared spectroscopy (FTIR), thermal analysis (TGA) and Raman spectroscopy, while the surface morphology of the resulting nanocomposites was studied using field emission scanning electron microscopy (FESEM). All data revealed that the external surface of MWBA nanocomposites was successfully coated with the respective polymer molecules through hydrophobic and electrostatic interactions with improved thermal profiles. The cell viability assay, which was performed on cultured normal embryonic mouse fibroblast cells, confirmed their excellent biocompatibility in phosphate-buffered saline aqueous media. Overall, our findings herein suggest that the synthesized biopolymer-coated MWBA nanocomposites are promising nanomaterials for drug delivery applications as they enhance the solubility and dispersibility of CNT with significantly reduced cytotoxic effect, especially in normal cells.

Surface Modification of Multiwalled Carbon Nanotubes with Engineered Self-Assembled RAFT Diblock Coatings

2014 ◽  
Vol 67 (1) ◽  
pp. 151 ◽  
Author(s):  
Yue Liu ◽  
Xiaojuan Hao ◽  
Lynne J. Waddington ◽  
Jieshan Qiu ◽  
Timothy C. Hughes
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Electrostatic Interactions ◽  
Diblock Copolymers ◽  
Raft Polymerization ◽  
Dispersion Stability ◽  
Multiwalled Carbon ◽  
Molecular Weights ◽  
Poly Ethylene ◽  
Positively Charged

A facile method to modify the surface of multiwalled carbon nanotubes (MWCNTs) via electrostatic interactions between polyelectrolytes and oxidized MWCNTs was developed. Diblock copolymers containing poly[2-(methacryloyloxy)ethyltrimethylammonium chloride] (PMETAC), a positively charged block, and poly(ethylene glycol) methacrylate (PEGMA), a neutral block, with tailored molecular weights and low polydispersities were synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization. Acid treated-MWCNTs were coated with the RAFT diblock copolymers to improve their dispersibility in aqueous phosphate buffered saline (PBS) solution. The short positively charged PMETAC block was designed to attach the block copolymers to the surface of MWCNTs via electrostatic interactions, whereas the PEGMA block improved dispersibility of the MWCNTs in aqueous solutions. Extensive screening of the diblock copolymers with different degrees of polymerization (DP) showed that the dispersion stability of the polymer-coated MWCNTs in PBS was greatly improved with increasing chain length of the PEGMA block. In particular, the MWCNTs coated with a diblock copolymer containing PEGMA (DP = 118, the longest block investigated) showed superior dispersion stability in both water and PBS solution.

Solubilization, characterization, and protein coupling analysis to multiwalled carbon nanotubes

2020 ◽  
pp. 095400832095803
Author(s):  
Juliane Glória ◽  
Walter Brito ◽  
Ariamna Gandarilla ◽  
Duniesky Larrude ◽  
Jacqueline Carlos ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Aqueous Media ◽  
Chemical Properties ◽  
Electron Microscopic ◽  
Multiwalled Carbon ◽  
Physical And Chemical ◽  
The Impact ◽  
Microscopic Techniques ◽  
And Chemical Properties

Since their discovery, carbon nanotubes were used for numerous applications in the most diverse knowledge areas. However, the lack of solubility of these molecules in aqueous media compromises their beneficial properties for certain applications. Several methods to solubilize carbon nanotubes are described, however, depending on the intended application, the impact that the solubilization has on the physical and chemical properties needs to be considered. In the present study, a simple methodology is described that utilizes polyvinylpyrrolidone combined with sonication and centrifugation to solubilize multiwalled carbon nanotubes. Proteins were coupled to the surface of the solubilized products and characterized using various spectroscopic and electron microscopic techniques, evaluating the characteristics and integrity of the nanoparticle after the process. It was successfully demonstrated that nanotubes can be solubilized through a simple technique, without compromising their chemical characteristics, which makes them suitable materials for use in biomedical applications, due to their biocompatibility and lack of toxicity, among others.

scholarly journals Comparing the Adsorption Performance of Multiwalled Carbon Nanotubes Oxidized by Varying Degrees for Removal of Low Levels of Copper, Nickel and Chromium(VI) from Aqueous Solutions

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 723 ◽  
Author(s):  
Marko Šolić ◽  
Snežana Maletić ◽  
Marijana Kragulj Isakovski ◽  
Jasmina Nikić ◽  
Malcolm Watson ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Carbon Nanotubes ◽  
Aqueous Solutions ◽  
Multiwalled Carbon Nanotubes ◽  
Electrostatic Interactions ◽  
Positive Impact ◽  
Molar Ratio ◽  
Multiwalled Carbon ◽  
Removal Of Heavy Metals ◽  
Low Levels

Functionalized multiwalled carbon nanotubes (MWCNTs) have drawn wide attention in recent years as novel materials for the removal of heavy metals from the aquatic media. This paper investigates the effect that the functionalization (oxidation) process duration time (3 h or 6 h) has on the ability of MWCNTs to treat water contaminated with low levels of Cu(II), Ni(II) and Cr(VI) (initial concentrations 0.5–5 mg L−1) and elucidates the adsorption mechanisms involved. Adsorbent characterization showed that the molar ratio of C and O in these materials was slightly lower for the oxMWCNT6h, due to the higher degree of oxidation, but the specific surface areas and mesopore volumes of these materials were very similar, suggesting that prolonging the functionalization duration had an insignificant effect on the physical characteristics of oxidized multiwalled carbon nanotubes (oxMWCNTs). Increasing the Ph of the solutions from Ph 2 to Ph 8 had a large positive impact on the removal of Cu(II) and Ni(II) by oxMWCNT, but reduced the adsorption of Cr(VI). However, the ionic strength of the solutions had far less pronounced effects. Coupled with the results of fitting the kinetics data to the Elowich and Weber–Morris models, we conclude that adsorption of Cu(II) and Ni(II) is largely driven by electrostatic interactions and surface complexation at the interface of the adsorbate/adsorbent system, whereas the slower adsorption of Cr(VI) on the oxMWCNTs investigated is controlled by an additional chemisorption step where Cr(VI) is reduced to Cr(III). Both oxMWCNT3h and oxMWCNT6h have high adsorption affinities for the heavy metals investigated, with adsorption capacities (expressed by the Freundlich coefficient KF) ranging from 1.24 to 13.2 (mg g−1)/(mg l−1)n, highlighting the great potential such adsorbents have in the removal of heavy metals from aqueous solutions.

scholarly journals Adsorption of Gold(I) and Gold(III) Using Multiwalled Carbon Nanotubes

2018 ◽  
Vol 8 (11) ◽  
pp. 2264 ◽  
Author(s):  
Francisco Alguacil
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Aqueous Media ◽  
Precious Metals ◽  
Order Kinetic ◽  
Chloride Medium ◽  
Multiwalled Carbon ◽  
Ph Values ◽  
Diffusion Controlled ◽  
Order Kinetic Model

Carbon nanotubes are materials that have been investigated for diverse applications including the adsorption of metals. However, scarce literature has described their behavior in the case of the adsorption of precious metals. Thus, this work reports the efficient adsorption of gold from cyanide or chloride media on multiwalled carbon nanotubes (MWCNTs). In a cyanide medium, gold was adsorbed from alkaline pH values decreasing the adsorption as the pH values were increased to more acidic values. In a chloride medium, the MWCNTs were able to load the precious metal and an increased HCl concentration (0.1–10 M), in the aqueous solution, had no effect on the gold uptake onto the nanotubes. From both aqueous media, the metal adsorption was well represented by the pseudo-second order kinetic model. In the cyanide medium, the film-diffusion controlled process best fitted the rate law governing the adsorption of gold onto the nanotubes, whereas in the chloride medium, the adsorption of the metal onto the nanotubes is best represented, both at 20 °C and 60 °C, by the particle-diffusion controlled process. With respect to the elution step, in cyanide medium gold loaded onto the nanotubes can be eluted with acidic thiourea solutions, whereas in the chloride medium, and due to that the adsorption process involved the precipitation of zero valent gold onto the multiwalled carbon nanotubes, the elution has been considered as a leaching step with aqua regia. From the eluates, dissolved gold can be conveniently precipitated as zero valent gold nanoparticles.

scholarly journals Carbon Nanotubes Interference with Luminescence-Based Assays

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4270
Author(s):  
Tomasz Szymański ◽  
Marcelina Kempa ◽  
Michael Giersig ◽  
Jakub Dalibor Rybka
Keyword(s):  
Carbon Nanotubes ◽  
Cell Viability ◽  
Multiwalled Carbon Nanotubes ◽  
Articular Chondrocytes ◽  
Multiwalled Carbon ◽  
Cell Viability Assay ◽  
Conflicting Information ◽  
Viability Assay ◽  
Normal Human

Carbon nanotubes (CNTs) are one of the most promising nanomaterials synthesized to date. Thanks to their unique mechanical, electronic, and optical properties, they have found a wide application in electronics in the production of biosensors and nanocomposites. The functionalization of multiwalled carbon nanotubes (MWCNTs) is aimed at making them biocompatible by adding hydrophilic groups on their surface, increasing their solubility and thus rendering them applicable in the regenerative medicine. So far, there is conflicting information about carbon nanotubes in biological systems. This paper investigates the effect of functionalized, oxidized, multiwalled carbon nanotubes (MWCNT-Ox) on the cytotoxicity of normal human articular chondrocytes (NHAC-kn cell line). Since absorbance-based and fluorescence-based assays were shown to interfere with carbon nanotubes, luminescence-based tests were carried out, as they work on a different method of detection and provide advantages over the mentioned ones. Cell viability and reactive oxygen species (ROS) tests were carried out. The cell viability assay showed that with the increasing MWCNTs concentration, the number of viable chondrocytes was significantly decreasing. Exposure to MWCNT-Ox indicated oxidative stress in the lowest investigated concentration with a decreased amount of ROS with higher concentrations. However, control experiments with adenosine triphosphate (ATP) and H2O2—molecules that are detected by the assays—showed that carbon nanotubes interfere directly with measurement, thus rendering the results unreliable. To understand the exact interference mechanisms, further studies must be taken. In conclusion, this study shows that luminescence-based tests yield erroneous results, confirming that in vitro experiments in the literature concerning carbon nanotubes should be analyzed with caution.

Effect of Multiwalled Carbon Nanotubes On Mechanical Properties of Concrete

2012 ◽  
Vol 2 (6) ◽  
pp. 166-168 ◽  
Author(s):  
Dr.T.Ch.Madhavi Dr.T.Ch.Madhavi ◽  
◽  
Pavithra.P Pavithra.P ◽  
Sushmita Baban Singh Sushmita Baban Singh ◽  
S.B.Vamsi Raj S.B.Vamsi Raj ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Multiwalled Carbon
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