Read by QxMD icon Read

Carboxylated single walled carbon nanotubes

Yun Ding, Rong Tian, Zhen Yang, Jianfa Chen, Naihao Lu
Previous studies have shown that carboxylated single-walled carbon nanotubes (SWCNTs) could be oxidatively biodegraded by neutrophil myeloperoxidase (MPO) and peroxynitrite (ONOO(-)). However, the biodegradation mechanism of nanotubes in macrophages has not been explored enough. Here, we showed that both MPO and ONOO(-) could effectively oxidize SWCNTs to generate shorter and oxidative nanotubes in vitro. SWCNTs were significantly degraded in zymosan-stimulated macrophages, and the degradation mechanism was dependent on MPO and ONOO(-)-driven oxidative pathways of activated macrophages, where NADPH oxidase was found to be a major determinant of the biodegradation process...
January 2017: Journal of Materials Science. Materials in Medicine
Daohui Zhao, Jian Zhou
The α-chymotrypsin (α-ChT) enzyme is extensively used for studying nanomaterial-induced enzymatic activity inhibition. A recent experimental study reported that carboxylized carbon nanotubes (CNTs) played an important role in regulating the α-ChT activity. In this study, parallel tempering Monte Carlo and molecular dynamics simulations were combined to elucidate the interactions between α-ChT and CNTs in relation to the CNT functional group density. The simulation results indicate that the adsorption and the driving force of α-ChT on different CNTs are contingent on the carboxyl density...
October 26, 2016: Physical Chemistry Chemical Physics: PCCP
Elizabeth I Braun, Rockford Draper, Paul Pantano
It is well known that surfactant-suspended carbon nanotube (CNT) samples can be purified by centrifugation to decrease agglomerates and increase individually-dispersed CNTs. However, centrifugation is not always part of protocols to prepare CNT samples used in biomedical applications. Herein, using carboxylated multi-walled CNTs (cMWCNTs) suspended in water without a surfactant, we developed a Boehm titrimetric method for the analysis of centrifuged cMWCNT suspensions and used it to show that the surface acidity of oxidized carbon materials in aqueous cMWCNT suspensions was enriched by ~40% by a single low-speed centrifugation step...
June 2016: Analytical Chemistry Research
Beatriz Fresco-Cala, Soledad Cárdenas, Miguel Valcárcel
A novel hybrid micro and meso porous silica monolith with embedded carbon nanoparticles (Si-CNPs monolith) was prepared inside a fused silica capillary (3cm in length) and used as a sorbent for solid-phase microextraction. The hybrid monolithic capillary was synthetized by hydrolysis and polycondensation of a mixture of tetraethoxysilane (TEOS), ethanol, and three different carbon nanoparticles such as carboxylated single-walled carbon nanotubes (c-SWCNTs), carboxylated multi-walled carbon nanotubes (c-MWCNTs), and oxidized single-walled carbon nanohorns (o-SWNHs) via a two-step catalytic sol-gel process...
October 14, 2016: Journal of Chromatography. A
Yun Ding, Rong Tian, Zhen Yang, Jianfa Chen, Naihao Lu
The binding of protein to carboxylated single-walled carbon nanotubes (SWCNTs) was believed to play an important role in the biological effects of nanotubes. However, the effects of protein-SWCNTs interactions on the oxidative degradation of nanotubes were not stressed enough. Here, we investigated the binding of human immunoglobulin G (IgG) to SWCNTs, and found that the preferred binding site was located in the Fc region of IgG. The hydrophobic and electrostatic interactions might be the crucial factors in stabilizing the binding of SWCNTs with IgG...
November 2016: Biophysical Chemistry
Hui Yang, Dianpeng Qi, Zhiyuan Liu, Bevita K Chandran, Ting Wang, Jiancan Yu, Xiaodong Chen
A soft thermal sensor with mechanical adaptability is fabricated by the combination of single-wall carbon nanotubes with carboxyl groups and self-healing polymers. This study demonstrates that this soft sensor has excellent thermal-response and mechanical adaptability. It shows tremendous promise for improving the service life of soft artificial intelligence robots and preventing thermal-sensitive electronics from the risk of damage by high temperature.
August 30, 2016: Advanced Materials
Yuan Sun, Zhizhou Zhang
Polydimethylsiloxane (PDMS) with exceptional fouling-release properties is extremely susceptible to the microfouling resulted from the colonization of the pioneer microorganisms in the marine environment. In this study, six carboxyl-modified multi-walled carbon nanotubes (cMWNTs) nanoparticles were incorporated into the PDMS matrix, respectively, in order to produce the cMWNTs-filled PDMS nanocomposites (CPs) with improved antifouling (AF) properties. The AF properties of the six CPs were examined via the field assays conducted in Weihai, China...
September 2016: World Journal of Microbiology & Biotechnology
Atul A Chaudhari, D'andrea Ashmore, Subrata Deb Nath, Kunal Kate, Vida Dennis, Shree R Singh, Don R Owen, Chris Palazzo, Robert D Arnold, Michael E Miller, Shreekumar R Pillai
BACKGROUND: Due to increasing antibiotic resistance, the use of silver coated single walled carbon nanotubes (SWCNTs-Ag) and antimicrobial peptides (APs) is becoming popular due to their antimicrobial properties against a wide range of pathogens. However, stability against various conditions and toxicity in human cells are some of the major drawbacks of APs and SWCNTs-Ag, respectively. Therefore, we hypothesized that APs-functionalized SWCNTs-Ag could act synergistically. Various covalent functionalization protocols described previously involve harsh treatment of carbon nanotubes for carboxylation (first step in covalent functionalization) and the non-covalently functionalized SWCNTs are not satisfactory...
2016: Journal of Nanobiotechnology
Bingyu Wang, Linda S Lee, Chenhui Wei, Heyun Fu, Shourong Zheng, Zhaoyi Xu, Dongqiang Zhu
Perfluoroalkyl acids (PFAAs) are highly stable, persistent, and ubiquitous in the environment with significant concerns growing with regards to both human and ecosystem health. Due to the high stability to both biological and chemical attack, the only currently feasible approach for their removal from water is adsorbent technology. The main objective of this study was to assess a covalent triazine-based framework (CTF) adsorbent for removal from aqueous solutions of perfluoro C4, C6, and C8 carboxylates and sulfonates including the two C8s most commonly monitored, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS)...
September 2016: Environmental Pollution
Patrícia Ramos, Marcos Schmitz, Daza Filgueira, Ana Paula Votto, Michael Durruthy, Marcos Gelesky, Caroline Ruas, João Yunes, Mariana Tonel, Solange Fagan, José Monserrat
Saxitoxins (STXs) are potent neurotoxins that also induce cytotoxicity through reactive oxygen species (ROS) generation. Carbon nanotubes (CNTs) are nanomaterials (NM) that can promote the 'Trojan horse' effect, facilitating the entry of toxic molecules to cells when adsorbed to NM. The interaction of pristine single-walled (SWCNT) and carboxylated (SWCNT-COOH) with STX was evaluated using ab initio simulation and bioassays using the cell line HT-22. Cells (5 × 10(4) cells/mL) were exposed to SWCNT and SWCNT-COOH (5 µg...
July 2, 2016: Environmental Toxicology and Chemistry
Ali Razzazan, Fatemeh Atyabi, Bahram Kazemi, Rassoul Dinarvand
Gemcitabine (GEM) is a highly hydrophil anticancer drug which extensively used in the clinic for the treatment of a range of solid tumors, including pancreatic and lung cancers. We have designed a drug delivery system based on single-walled carbon nanotubes (SWCNTs) for the anticancer drug GEM, which has limitations under biological conditions, by using polyethylene glycol (PEG) to obtain nanoconjugates with high loading capacity, controlled drug release and effective cytotoxicity. Raw SWCNTs were functionalized through carboxylation, acylation, PEGylation and finally GEM conjugation via a cleavable ester bond...
June 14, 2016: Current Drug Delivery
Takahisa Ohta, Yasuhiko Hashida, Fumiyoshi Yamashita, Mitsuru Hashida
Single-walled carbon nanotubes (SWCNTs) attract great interest in biomedical applications including drug and gene delivery. In this study, we developed a novel delivery system using SWCNTs associated with designed polycationic and amphiphilic peptides. Wrapping of SWCNTs with H-(-Lys-Trp-Lys-Gly-)7-OH [(KWKG)7] resulted in stable dispersion in water, but the composite aggregated in the buffered solution. This dispersion instability was also evident in a cell culture medium with fetal bovine serum. To improve the aqueous dispersibility, the SWCNTs-(KWKG)7 composite was further modified with polyethylene glycol (PEG) at the lysine residues via amide bond formation and the highest modification extent of 13...
September 2016: Journal of Pharmaceutical Sciences
Han Ding, Xin Li, Jun Wang, Xiaojian Zhang, Chao Chen
The adsorption of six kinds of chlorophenols on pristine, hydroxylated and carboxylated single-walled carbon nanotubes (SWCNTs) has been investigated. Pseudo-first order and pseudo-second order models were used to describe the kinetic data. All adsorption isotherms were well fitted with Langmuir, Freundlich and Polanyi-Manes models, due to surface adsorption dominating the adsorption process. The close linear relationship between logKow and logKd suggested that hydrophobicity played an important role in the adsorption...
May 2016: Journal of Environmental Sciences (China)
Chee Meng Ng, Hwei-San Loh, Kasturi Muthoosamy, Nanthini Sridewi, Sivakumar Manickam
PURPOSE: The high aspect ratio of carbon nanotubes (CNTs) allows the attachment of compounds that enhance the functionality of the drug vehicle. Considering this, use of CNTs as a multifunctional insulin carrier may be an interesting prospect to explore. MATERIALS AND METHODS: The carboxylic acid groups were functionalized on the sidewalls of single-walled CNTs (SWCNTs) followed by diimidation to form amide bonds with the amine groups of the insulin. RESULTS: Scanning transmission electron microscopy and transmission electron microscopy establish clear conjugation of insulin onto the surface of nanotube sidewalls...
2016: International Journal of Nanomedicine
Yuan Sun, Yanhe Lang, Qian Sun, Shuang Liang, Yongkang Liu, Zhizhou Zhang
In this paper, two carbon nanotube (CNT) nanofillers, namely the multi-walled carbon nanotubes (MWCNTs) and the carboxyl-modified MWCNTs (cMWCNTs), were introduced into the polydimethylsiloxane (PDMS) matrix respectively, in order to produce the PDMS composites with reinforced anti-biofouling properties. The anti-biofouling capacity of the silicone-based coatings, including the unfilled PDMS (P0), the MWCNTs-filled PDMS (PM) and the cMWCNTs-filled PDMS (PC), was examined via the field assays conducted in Weihai, China...
September 1, 2016: Colloids and Surfaces. B, Biointerfaces
Ali Razzazan, Fatemeh Atyabi, Bahram Kazemi, Rassoul Dinarvand
Gemcitabine (GEM) is an anticancer agent widely used in non-small cell lung and pancreatic cancers. The clinical use of GEM has been limited by its rapid metabolism and short plasma half-life. These restrictions lead to frequent administration of high drug doses which can cause severe side effects. Therefore, new delivery strategies are needed aiming toward improved therapeutic effects. Single-walled carbon nanotubes (SWCNTs) are emerging as promising carriers for drug delivery due to their unique properties including high drug loading capacities, notable cell membrane penetrability and prolonged circulation times...
May 2016: Materials Science & Engineering. C, Materials for Biological Applications
Nalinikanth Kotagiri, Joshua Sakon, Haewook Han, Vladimir P Zharov, Jin-Woo Kim
Cancer nanomedicines are opening new paradigms in cancer management and recent research points to how they can vastly improve imaging and therapy through multimodality and multifunctionality. However, challenges to achieving optimal efficacy are manifold starting from processing materials and evaluating their intended effectiveness on biological tissue, to developing new strategies aimed at improving transport of these materials through the biological milieu to the target tissue. Here, we report a fluorescent derivative of a beta-lactam antibiotic, ampicillin (termed iAmp) and its multifunctional physicobiochemical characteristics and potential as a biocompatible shielding agent and an effective dispersant...
July 7, 2016: Nanoscale
Wen-Che Hou, Chen-Jing He, Yi-Sheng Wang, David K Wang, Richard G Zepp
Single-walled carbon nanotubes (SWCNTs) with proper functionalization are desirable for applications that require dispersion in aqueous and biological environments, and functionalized SWCNTs also serve as building blocks for conjugation with specific molecules in these applications. In this study, we examined the phototransformation of carboxylated SWCNTs and associated amorphous carbon impurities in the presence or absence of H2O2 under simulated sunlight conditions. We found that while carboxylated SWCNTs were rather unreactive with respect to direct solar photolysis, they photoreacted in the presence of H2O2, forming CO2 and strongly aggregated SWCNT products that precipitated...
April 5, 2016: Environmental Science & Technology
Judith H Bartha-Vári, Monica I Toşa, Florin-Dan Irimie, Diána Weiser, Zoltán Boros, Beáta G Vértessy, Csaba Paizs, László Poppe
Carboxylated single-walled carbon nanotubes (SwCNTCOOH) were used as a support for the covalent immobilization of phenylalanine ammonia-lyase (PAL) from parsley by two different methods. The nanostructured biocatalysts (SwCNTCOOH-PAL(I) and SwCNTCOOH-PAL(II)) with low diffusional limitation were tested in the batch-mode kinetic resolution of racemic 2-amino-3-(thiophen-2-yl)propanoic acid (1) to yield a mixture of (R)-1 and (E)-3-(thiophen-2-yl)acrylic acid (2) and in ammonia addition to 2 to yield enantiopure (S)-1...
April 7, 2015: ChemCatChem
J R Lawrence, M J Waiser, G D W Swerhone, J Roy, V Tumber, A Paule, A P Hitchcock, J J Dynes, D R Korber
Commercial production of nanoparticles (NP) has created a need for research to support regulation of nanotechnology. In the current study, microbial biofilm communities were developed in rotating annular reactors during continuous exposure to 500 μg L(-1) of each nanomaterial and subjected to multimetric analyses. Scanning transmission X-ray spectromicroscopy (STXM) was used to detect and estimate the presence of the carbon nanomaterials in the biofilm communities. Microscopy observations indicated that the communities were visibly different in appearance with changes in abundance of filamentous cyanobacteria in particular...
May 2016: Environmental Science and Pollution Research International
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"