Biocompatible chitosan/polyethylene glycol/multi-walled carbon nanotube composite scaffolds for neural tissue engineering / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Carbon nanotube (CNT) composite materials are very attractive for use in neural tissue engineering and biosensor coatings. CNT scaffolds are excellent mimics of extracellular matrix due to their hydrophilicity, viscosity, and biocompatibility. CNTs can also impart conductivity to other insulating materials, improve mechanical stability, guide neuronal cell behavior, and trigger axon regeneration. The performance of chitosan (CS)/polyethylene glycol (PEG) composite scaffolds could be optimized by introducing multi-walled CNTs (MWCNTs). CS/PEG/CNT composite scaffolds with CNT content of 1%, 3%, and 5% (1%=0.01 g/mL) were prepared by freeze-drying. Their physical and chemical properties and biocompatibility were evaluated. Scanning electron microscopy (SEM) showed that the composite scaffolds had a highly connected porous structure. Transmission electron microscope (TEM) and Raman spectroscopy proved that the CNTs were well dispersed in the CS/PEG matrix and combined with the CS/PEG nanofiber bundles. MWCNTs enhanced the elastic modulus of the scaffold. The porosity of the scaffolds ranged from 83% to 96%. They reached a stable water swelling state within 24 h, and swelling decreased with increasing MWCNT concentration. The electrical conductivity and cell adhesion rate of the scaffolds increased with increasing MWCNT content. Immunofluorescence showed that rat pheochromocytoma (PC12) cells grown in the scaffolds had characteristics similar to nerve cells. We measured changes in the expression of nerve cell markers by quantitative real-time polymerase chain reaction (qRT-PCR), and found that PC12 cells cultured in the scaffolds expressed growth-associated protein 43 (GAP43), nerve growth factor receptor (NGFR), and class III β‍-tubulin (TUBB3) proteins. Preliminary research showed that the prepared CS/PEG/CNT scaffold has good biocompatibility and can be further applied to neural tissue engineering research.

Preparation of PEOz-modified single-walled carbon nanotube paclitaxel delivery system and evaluation of its anti-tumor effect in vitro / 中草药

Objective: To prepare a PEOz modified single-walled carbon nanotube delivery system (PEOz-SWCNT) with the anti- tumor drug paclitaxel (PTX) as a model drug (PTX@PEOz-SWCNT) and evaluate its physical and chemical properties, in vitro drug release, biocompatibility, and in vitro antitumor effects. Methods: PEOz-SWCNT was synthesized by chemical coupling method, and the products were characterized by UV-Vis spectroscopy (UV-Vis) and infrared spectroscopy (FTIR). The particle size and Zeta potential of PEOz-SWCNT were measured. The drug-loaded complex PTX@PEOz-SWCNT was prepared and the loading efficiency and encapsulation efficiency were measured. The dialysis method was used for in vitro drug release. The safety of the application of PEOz-SWCNT was evaluated by in vitro hemolysis test. The MTT method was used to evaluate the biocompatibility of the material and the growth inhibition rate of the drug-loaded complex on MCF-7 cells. The uptake of Coumarin-6 (C6)-labeled vector in MCF-7 cells was examined by fluorescence inversion microscope. Results: The average particle size of PEOz-SWCNT was (219.8 ± 2.9) nm and the Zeta potential was (-35.23 ± 0.74) mV. The loading efficiency of PTX@PEOz-SWCNT was (38.19 ± 0.74) %, and the encapsulation efficiency was (94.38 ± 0.94)%. The drug release rate was significantly accelerated at pH 5.0, showing obvious pH responsiveness. There was no obvious hemolysis when the concentration of PEOz-SWCNT was below 0.4 mg/mL. The biocompatibility of PEOz-SWCNT on Hela cells was good, and the PTX@PEOz-SWCNT could significantly enhance the cell growth inhibition rate on MCF-7 cells. The in vitro antitumor activity test results showed that the cell uptake of the C6@PEOz-SWCNT was increased compared to C6@SWCNT. Conclusion: PTX@PEOz-SWCNT drug delivery system is promising in tumor-targeted drug delivery.

Preparation and Characterization of PTX-MWNTs-COOH and Its in Vitro Release / 中国药学杂志

OBJECTIVE: To prepare and characterize PTX-MWCNTs-COOH complex and study its in vitro release properties. METHODS: The PTX-MWCNTs-COOH complex was prepared by solvent blending method with paclitaxel as drug,phospholipid as surfactant. It was characterized by laser particle size analyzer,transmission electron microscope (TEM) and DSC analysis. The drug loading was determined by filtration membrane together HPLC method and the entrapment efficiency was determined by microcolumn separation together HPLC method. The in vitro release of the PTX-MWCNTs-COOH complex was studied in PBS buffer at pH 7.4(containing 1% Tween-80) with revers dialysis method. RESULTS: The Zeta potential of PTX-MWCNTs-COOH complex was (-24.5±1.01) mV,the drug loading was(50.09±0.02)%,and the entrapment efficiency was (76.80±0.02)%. The cumulative release in vitro was perfect. CONCLUSION: PTX-MWCNTs-COOH showed good physicochemical properties such as high drug loading and entrapment efficiency. The method of reverse dialysis can be used to study the release behavior of PTX-MWCNTs-COOH in vitro.

Advances of functionalized carbon nanotubes in diagnosis and treatment of tumor / 中国药科大学学报

@#Carbon nanotubes have become a kind of superior antitumor drug and gene carrier due to their special cylindrical structure with high loading capacity and easy penetration into the cell membrane. With the gradual development of researches on carbon nanotubes, their applications in tumor photothermal therapy and diagnosis have also become current research hotspots. However, chemical inertness and aggregation of carbon nanotubes have limited their clinical application. To overcome their drawbacks, researchers would functionalize the carbon nanotubes before further researches. In this article, applications of functionalized carbon nanotubes in cancer chemotherapy and gene therapy, photothermal therapy and cancer diagnosis are summarized.

Preparation of Carboxylated Multi-Walled Carbon Nanotubes Loaded with Podophyllotoxin and Their Transdermal Penetration / 中国药学杂志

OBJECTIVE: To study the preparation of carboxylated multi-walled carbon nanotubes loaded with podophyllotoxin (PPT-CNTs-COOH) as well as the characteristics of the in vitro transdermal penetration. METHODS: PPT-CNTs-COOH was prepared by freezing milling method; IR, UV, XRD, and TGA were used to characterize the PPT-CNTs-COOH; HPLC method was used for determination of the content of podophyllotoxin loaded in the carboxylated multi-walled carbon nanotubes; franze diffusion cells method was used to determine the drug transdermal penetration rate. RESULTS: The IR spectrum of PPT-CNTs-COOH showed the main absorption peaks of PPT and CNTs-COOH and the peaks changed obviously. Compared with free PPT, the UV absorption peaks of PPT-CNTs-COOH changed obviously. The PPT content in the CNTs-COOH gel was 58.0 μg·mg-1; the transdermal penetration rate of PPT gel was 7.08 μg·cm-2·h-1 and that of the PPT-CNTs-COOH gel was 3.03 μg·cm-2·h-1; the skin retention of PPT-CNTs-COOH gel was 3.04 μg·cm-2, far less than the 1.52 μg·cm-2 of PPT gel. Mild irritation developed within 24 h following removal of the PPT-CNTs-COOH gel, and disappears after 72 h. CONCLUSION: Podophyllotoxin can successfully be loaded into the carboxylated multi-wall carbon nanotubes by using the frozen ball milling method. The product has remarkable sustained release effect in vitro and high retention in skin, which is beneficial to transdermal delivery.

A Hydrogen Peroxide Sensor Based on Palladium Nanoparticles Loading to Poly(amidoamine) Dendrimers Functionalized Carbon Nanotubes / 分析化学

The fourth generation poly( amidoamine) dendrimers ( G4. 0 PAMAM) functionalized multiwalled carbon nanotube ( G4 . 0-MWCNTs ) was prepared by amidation between carboxylated multiwalled carbon nanotube (MWCNTs) and G4. 0 PAMAM. Then a novel hydrogen peroxide (H2O2) sensor was fabricated by electrodepositing Pd nanoparticles (NPs) on a glassy carbon electrode (GCE) modified with G4. 0-MWCNTs composites. The modified electrode was characterized by field emission scanning electron microscopy ( FESEM) , cyclic voltammetry ( CV) and electrochemical impedance spectroscopy ( EIS) . A large amounts of highly dispersion PdNPs could be well loaded on the surface of the G4. 0-MWCNTs, and the modified electrode exhibited excellent electrocatalytic activity towards the reduction of H2 O2 . Under the optimized conditions, the reduction peak currents of H2 O2 were linear to their concentrations in the range from 1. 0 × 10-9 mol/L to 1. 0×10-3 mol/L and the limit of detection of 2. 3×10-8 mol/L was obtained. The recovery of standard addition for human serum samples was 96 . 7%-103 . 1%.

Preparation of ethylenediamine functionally-modified multi-walled carbon nanotubes and biocompatibility on PC12 cells / 中国药学杂志

OBJECTIVE: To prepare multi-walled carbon nanotubes-ethylenediamine (MWCNTs-EDA) compound with low toxicity and belter dispersion using EDA functionally modified-multi-walled carbon nanotubes to lay a foundation for the further research of loading drugs with carbon nanotubes. METHODS: MWCNTs-EDA compound was synthesized by covalent crosslinking with carboxylated carbon nanotubes (MWCNTS-COOH) and ethylenediamine, and then scanning electron microscopy (SEM), transmission electron microscopy (TEM), infrared spectroscopy (KTIR), thermal gravimetric analysis (TG), Raman spectrum, and Zeta potential determination were used to characterize the compound, and the dispersion uniformity of MWCNTs before and after functionalization were examined. MIT assay and flow cytometry test were used to measure the toxicity of the compound against phcochromocytoma cells. RESULTS: The results of SEM, TEM, FTIR, TG, Raman, and Zeta potential analysis confirmed that MWCNTs had successfully received the EDA. The dispersibility test showed that MWCNTs-EDA had better dispersion stability in water. MTT assay and flow cytometry test showed that EDA functionally-modified MWCNTs greatly reduced the cytotoxicity of the MWCNTs. CONCLUSION: The EDA functionally-modified MWCNTs has significantly improved dispersibility, significantly reduced in vitro cytotoxicity, and better biocompatibility.

Comparative study of adsorptive role of carbonaceous materials in removal of UV-active impurities of paclitaxel extracts / 药物分析学报

Graphite oxide (GO) and reduced graphene oxide (rGO) nanosheets were synthesized with a low-cost manufacturing method. The morphology and structures of the synthesized samples were studied using X-ray diffraction (XRD), atomic force microscopy (AFM), Fourier-transform infrared (FTIR) and Raman spectroscopy. The efficiencies of GO and rGO as novel candidate adsorbents in the pre-purification of paclitaxel were compared and contrasted with those of commercial graphite (Gt), graphene (G) and multi-wall carbon nanotube (MWCNT). According to UV–vis and HPLC analyses, rGO was evaluated as the best absorbent for the removal of impurities in pre-purification of paclitaxel from plant cell cultures. In contrast, the GO had the poorest proficiency for paclitaxel pre-purification in comparison with the other carbonaceous adsorbents. This is attributed to the existence of many localized defects in the π-structure of GO that is related to weakness ofπ–πstacking interactions between crude extract impurities and GO.

Electrochemical Behavior and Determination of Pyridoxine Hydrochloride at Graphene-Carbon Nanotubes/Poly(nicotinic acid) Modified Electrode / 分析化学

Graphene ( GN) and multiwalled carbon nanotubes ( MWCNT) composites were coated on glassy carbon electrode ( GCE ) and then poly ( nicotinic acid ) ( PNA ) was electrodeposited on the modified electrode. The electrochemical behavior of pyridoxine hydrochloride ( VB6 ) was investigated at the modified electrode by cyclic voltammetry ( CV ) and differential pulse voltammetry ( DPV ) . Results showed the oxidation current of VB6 at the GN-MWCNT/PNA/GCE was obviously larger than that at GCE, PNA/GCE and GN/MWCNT/GCE. The oxidation process of VB6 was an irreversible diffusion-controlled process involving one electron and two protons. The liner range between the peak current intensity of DPV and the concentration of VB6 was 0 . 05-200 μmol/L with a detection limit of 0 . 02 μmol/L ( S/N=3 ) . The modified electrode showed a good reproducibility with a relative standard deviation of 3 . 1% ( n=8 ) . The proposed method was applied to the analysis of vitamin B6 in vitamin B6 tablets and compound vitamin B tablets with recoveries between 96 . 1%-104 . 5%.

Preparation and properties of chitosan/β-glycerophosphate thermosensitive hydrogel containing amino-carbon nanotubes / 中国药学杂志

OBJECTIVE: To synthesis chitosan/β-glycerophosphate (CS/β-GP) thermosensitive hydrogel containing multi-walled carbon nanotubes-polyethyleneimine (MWCNTs-PEI) complexes and to lay a foundation for further research of dual slow-release delivery system. METHODS: Chitosan thermosensitive hydrogel containing MWCNTs-PEI was prepared by MWCNTs-PEI dispersed to the chitosan thermosensitive hydrogel. As the indicator of the gelling time, the experiment studied the effect of β-GP concentration, pH, temperature and MWCNTs-PEI composite quality on the thermosensitive chitosan hydrogel, and then it was charactered by using transmission electron microscopy (SEM), infrared spectrometer(IR), and initially investigated in vivo compatibility. RESULTS: The dynamic rheology method investigated the gelling temperature were about 37.0°C. Within a certain range, the gelling time of thermosensitive chitosan hydrogel was shortened with the increase of concentration of β-GP, pH, temperature, and the quality of MWCNTs-PEI complexes, and they could be transformed into the hydrogel in vivo. The addition of MWCNTs-PEI complex didn't react chemically with the thermosensitive chitosan hydrogel and significantly make the holes of the chitosan thermosensitive hydrogel smaller by SEM and FT-IR, eventually leading to the swelling rate and the corrosional ratio decrease. CONCLUSION: Chitosan/β-glycerophosphate thermosensitive hydrogel containing amino-carbon nanotubes has a rapid gelation and good temperature-sensitivity, which can serve as a good double sustained-release carrier.

Carbon nanotubes as a novel drug delivery system for anticancer therapy: a review

Carbon nanotubes (CNTs) were discovered in 1991 and shown to have certain unique physicochemical properties, attracting considerable interest in their application in various fields including drug delivery. The unique properties of CNTs such as ease of cellular uptake, high drug loading, thermal ablation, among others, render them useful for cancer therapy. Cancer is one of the most challenging diseases of modern times because its therapy involves distinguishing normal healthy cells from affected cells. Here, CNTs play a major role because phenomena such as EPR, allow CNTs to distinguish normal cells from affected ones, the Holy Grail in cancer therapy. Considerable work has been done on CNTs as drug delivery systems over the last two decades. However, concerns over certain issues such as biocompatibility and toxicity have been raised and warrant extensive research in this field.

Os nanotubos de carbono foram descobertos em 1991 e suas propriedades físico-químicas únicas demonstradas, despertando interesse em sua aplicação em vários campos, incluindo a entrega liberação de fármacos. As propriedades únicas dos nanotubos de carbono, tais como a facilidade de captação pela célula, carga alta de fármaco, ablação térmica, entre outras, tornaram-nos úteis para terapia de câncer, uma das doenças mais difíceis dos tempos modernos, pois sua terapia envolve a distinção entre as células normais saudáveis e as afetadas pela doença. Os nanotubos de carbono têm um papel importante nessa área porque fenômenos como EPR permitem que estes possam distinguir as células normais das afetadas, que é o Santo Graal na terapia do câncer. Trabalho considerável tem sido feito ao longo das duas últimas década com nanotubos de carbono, como sistemas de liberação de fármacos. No entanto, preocupações sobre algumas questões, como biocompatibilidade e toxicidade, surgiram ao longo do tempo, demandando extensas pesquisa nesse campo.

Single wall carbon nanotube induced inflammation in cruor-fibrinolysis system / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To study single wall carbon nanotubes (SWCNT) and its role in inducing inflammatory cytokines in the cruor-fibrinolysis system of rat.</p><p><b>METHODS</b>Twenty one Wistar rats were divided into four groups: 1) control; 2) low-dose SWCNT (0.15 mg/kg BW); 3) medium-dose SWCNT (0.75 mg/kg BW); 4) high-dose SWCNT (1.5 mg/kg BW). Intratracheal instillation of SWCNT suspensions was administered to rats once per day for 21 days. In order to assess the exposure effect of SWCNT to the rats, activity of Inflammatory cytokine was measured and markers of cruor-fibrinolysis system were studied via ELSIA. Also, change in clotting time was recorded and histopathology was studied.</p><p><b>RESULTS</b>IL-6 and IL-8 concentrations of rats exposed to SWCNT were significantly higher than those in controls (P<0.05). The activity of inflammatory cytokines and histopathological change indicated that oxidative damage occurred. Change in clotting time in rats exposed to SWCNT decreased compared with controls. Meanwhile, t-PA (tissue-tupe plassminogen activator) and AT-III (antithrombin-III) levels in rats exposed to particulates increased or decreased significantly compared with controls (P<0.05). A similar trend was observed for D-dimer (D2D) levels, indicating that SWCNT can impact the cruor-fibrinolysis system of rat.</p><p><b>CONCLUSION</b>The results from our study suggest that an increased procoagulant activity and reduced fibrinolytic activity in rats exposed to SWCNT can cause pulmonary oxidative stress and inflammation, due to the release of pro-thrombotic and inflammatory cytokines into the blood circulation of rat.</p>

Preparation of multi-walled carbon nanotubes-polyethyleneimine composite and its cytotoxicity on PC12 cells / 中国药学杂志

OBJECTIVE: To synthesize water-soluble multi-walled carbon nanotubes-polyethyleneimine (MWCNTs-PEI) composite with low cytotoxicity and to lay a foundation for further research of loading drugs with carbon nanotubes. METHODS: MWCNTs-PEI composite was prepared by modifying carboxylated multi-walled carbon nanotubes(MWCNTs-COOH) with polyethylene (PEI), and then the composite was characterized by transmission electron microscopy, infrared spectra, UV spectra and thermalgravimetric analysis. The cytotoxicity of the composite on PC12 cells was measured by methyl thiazolyl tetrazolium(MTT) assay to preliminarily evaluate its biocompatibility. RESULTS: The dissolubilities of MWCNTs-PEI and MWCNTs-COOH complexes were respectively 1.009 and 0.0601 mg · mL-1, and the former was about 16 times of the latter. The cytotoxicity of MWCNTs-PEI composite on PC 12 cells was significantly milder than that of MWCNTs-COOH composite as indicated by MTT assay (P < 0.05). CONCLUSION: MWCNTs-PEI composite not only improves the dispersibility of carbon nanotubes, but also reduces its in vitro cell toxicity.

Interaction of nucleic acids with carbon nanotubes and dendrimers.

Nucleic acid interaction with nanoscale objects like carbon nanotubes (CNTs) and dendrimers is of fundamental interest because of their potential application in CNT separation, gene therapy and antisense therapy. Combining nucleic acids with CNTs and dendrimers also opens the door towards controllable self-assembly to generate various supra-molecular and nano-structures with desired morphologies. The interaction between these nanoscale objects also serve as a model system for studying DNA compaction, which is a fundamental process in chromatin organization. By using fully atomistic simulations, here we report various aspects of the interactions and binding modes of DNA and small interfering RNA (siRNA) with CNTs, graphene and dendrimers. Our results give a microscopic picture and mechanism of the adsorption of single- and double-strand DNA (ssDNA and dsDNA) on CNT and graphene. The nucleic acid–CNT interaction is dominated by the dispersive van der Waals (vdW) interaction. In contrast, the complexation of DNA (both ssDNA and dsDNA) and siRNA with various generations of poly-amido-amine (PAMAM) dendrimers is governed by electrostatic interactions. Our results reveal that both the DNA and siRNA form stable complex with the PAMAM dendrimer at a physiological pH when the dendrimer is positively charged due to the protonation of the primary amines. The size and binding energy of the complex increase with increase in dendrimer generation. We also give a summary of the current status in these fields and discuss future prospects.

Multi-Walled Carbon Nanotube (MWCNT) Dispersion and Aerosolization with Hot Water Atomization without Addition of Any Surfactant

OBJECTIVES: Carbon nanotubes are an important new class of technological materials that have numerous novel and useful properties. Multi-walled carbon nanotubes (MWCNTs), which is a nanomaterial, is now in mass production because of its excellent mechanical and electrical properties. Although MWCNTs appear to have great industrial and medical potential, there is little information regarding their toxicological effects on researchers and workers who could be exposed to them by inhalation during the handling of MWCNTs. METHODS: The generation of an untangled MWCNT aerosol with a consistent concentration without using surfactants that was designed to be tested in in vivo inhalation toxicity testing was attempted. To do this, MWCNTs were dispersed in deionized water without the addition of any surfactant. To facilitate the dispersion of MWCNTs in deionized water, the water was heated to 40degrees C, 60degrees C, and 80degrees C depending on the sample with ultrasonic sonication. Then the dispersed MWCNTs were atomized to generate the MWCNT aerosol. After aerosolization of the MWCNTs, the shapes of the NTs were examined by transmission electron microscopy. RESULTS: The aerosolized MWCNTs exhibited an untangled shape and the MWCNT generation rate was about 50 mg/m3. CONCLUSION: Our method provided sufficient concentration and dispersion of MWNCTs to be used for inhalation toxicity testing.

Three Electrodes Biosensor for Alcohol in Whole Blood Based on Multi-wall Carbon-nanotube / 分析化学

A novel disposable three electrodes blood alcohol biosensor strip was fabricated by a screen printing technique. Multi-wall carbon nanotube(MWCNT), Meldola′s(MB), alcohol dehydrogenase(ADH)and nicotinamide adenine dinucleotide cofactor (NAD+) were modified on the surface of the carbon working electrode. Then hydrophilic membrane was stuck in the outermost of the three electrodes to make a reaction camera of 5 μL. Experimental results indicated that the biosensor possessed good accuracy and stability, the linear response range was 0.5-20 mmol/L with correlation coefficient of 0.9949, detection limit was 0.22 mmol/L, and the response time was less than 15 s. Some influencing factors to the biosensor were investigated, such as the pH, temperature and interferences. Correlation analysis showed that there was a significant correlation between the methods of biosensor and the headspace vapor phase chromatography in 10 whole blood samples(r=0.97583). Small volume whole blood sucked using siphonage to detect blood alcohol directly and quantitatively was the obvious character of the biosensor.

Developments in drug delivery with special reference to nanotechnology: A review.

With the emergence of nanoscience as a distinct speciality in recent times, various methods have been introduced in pharmaceuticals to produce drugs which are more efficacious and less hazardous. Nanomedicine is an offshoot of nanotechnology, which deals with the employment of devices less than 200 nanometres in size, in various diagnostic and therapeutic procedures. Nanocarriers get concentrated preferentially in tumours, inflammatory sites, and at antigen sampling sites. Once accumulated at the target site, they can act as a local drug depot at the disease site. Nanomaterials comprise carbon-based particles, such as fullerenes, various organic dendrimers, liposomes, and other polymeric compounds. Quantom dots, nanotubes and nanoparticles, nanocapsules and nanospheres, nanoemulsions, nanosuspensions, and polymeric phospholipid micelles are a few that are being increasingly tried in the nano drug delivery system. However, it is important to remember that nanoparticles can act on living cells at the nanolevel, producing not only biologically desirable, but also undesirable effects

Pulmonary Toxicity of Three Typical Nanomaterials Caused by Intratracheal Instillation in Rats / 环境与健康杂志

Objective To investigate the toxic effect of nona-ferroso-ferric oxide(Nano-Fe_3O_4),nano-silicon dioxide(Nano- SiO_2)and single walled carbon nanotubes(SWCNTs)on the lung and mechanism in rats.Methods Fourty-nine Wistar rats were randomly divided into 7 groups,the control group,low and high dose groups of three nanomaterials.The rats were exposed by intratracheal instillation once two days for 5 weeks,and then killed by abdominal aorta bloodletting.The pathology of lung,lactate dehydrogenase(LDH),total antioxidant capacity(T-AOC),superoxide dismutase(SOD),malondialdehyde(MDA),interleukin-1(IL- l),interleukin-6(IL-6)and tumor necrosis factor-?(TNF-?)in bronchoalveolar lavage fluid(BALF)were determined.Results The fibrous tubercle and the matrix inflammation of lung tissue was found in the experimental groups.The activities of T-AOC and SOD decreased while IL-6 concentration increased significantly in the experimental groups(P

Effects of Different Dose of Multi-Walled Carbon Nanotube on the Cellular Proliferation of HEK293 Cells / 医学研究杂志

Objective To study the effects of Multi-Walled Carbon Nanotube with different doses on the cellular proliferation of human embryo kidney 293 cells.Methods The cultured human embryo kidney cell line 293 was seeded into 96-well plates and various concentrations of Multi-Walled Carbon Nanotube were added into different groups of culture.Methyl thiazolyl tetrazolium(MTT)assay were applied to detect the cellular viabilities after being incubated with Multi-Walled Carbon Nanotube for 48 hours and the results were calculated with specific static software to protract the cell viability curve.Results The Multi-Walled Carbon Nanotube had different effects of inhibiting the multiplies of 293 cells depending on its concentrations.In addition,when the concentration of Multi-Walled Carbon Nanotube reached over 0.5ug/ml,the inhibition became significantly.Conclusions Multi-Walled Carbon Nanotube can penetrate the cell membrane of 293 cells to influence the activities of cells and the ability of proliferation will be decreased significantly when the concentration came to some degree.Therefore,the safety dosage of the Multi-Walled Carbon Nanotube on human normal embryo kidney 293 cells were estimated in this research.

Progress in carbon nanotube based dental ceramic material / 国际生物医学工程杂志

Carbon nantubes composites draws more and more attention these days. Its application provides new potential for the reinforcement and toughness of dental ceramic. In this paper, the properties of carbon nanotube, carbon nanotube based ceramic composites and its mechanics of toughness, and the future trend of carbon nanotube in dental ceramic material, have been reviewed.