Nanotubes, Carbon ; adverse effects ; chemistry

BACKGROUND: In the search for more powerful tools for diagnoses of endemic diseases in resource-limited settings, we have been analyzing technologies with potential applicability. Increasingly, the process focuses on readily accessible bodily fluids combined with increasingly powerful multiplex capabilities to unambiguously diagnose a condition without resorting to reliance on a sophisticated reference laboratory. Although these technological advances may well have important implications for the sensitive and specific detection of disease, to date their clinical utility has not been demonstrated, especially in resource-limited settings. Furthermore, many emerging technological developments are in fields of physics or engineering, which are not readily available to or intelligible to clinicians or clinical laboratory scientists. CONTENT: This review provides a look at technology trends that could have applicability to high-sensitivity multiplexed immunoassays in resource-limited settings. Various technologies are explained and assessed according to potential for reaching relevant limits of cost, sensitivity, and multiplex capability. Frequently, such work is reported in technical journals not normally read by clinical scientists, and the authors make enthusiastic claims for the potential of their technology while ignoring potential pitfalls. Thus it is important to draw attention to technical hurdles that authors may not be publicizing. SUMMARY: Immunochromatographic assays, optical methods including those involving waveguides, electrochemical methods, magnetorestrictive methods, and field-effect transistor methods based on nanotubes, nanowires, and nanoribbons reveal possibilities as next-generation technologies.
Endemic Diseases ; Health Resorts ; Immunoassay ; Immunochromatography ; Nanotubes ; Nanotubes, Carbon ; Nanowires

OBJECTIVES: In this study, the effect of tube length and outer diameter (OD) size of hydroxylated-multi walled carbon nanotubes (OH-MWCNTs) on their uptake and toxicity was investigated in the nematode Caenorhabditis elegans using a functional mutant analysis. METHODS: The physicochemical properties of three different OH-MWCNTs were characterized. Uptake and toxicity were subsequently investigated on C. elegans exposed to MWCNTs with different ODs and tube lengths. RESULTS: The results of mutant analysis suggest that ingestion is the main route of MWCNTs uptake. We found that OH-MWCNTs with smaller ODs were more toxic than those with larger ODs, and OH-MWCNTs with shorter tube lengths were more toxic than longer counterparts to C. elegans. CONCLUSIONS: Overall the results suggest the aspect ratio affects the toxicity of MWCNTs in C. elegans. Further thorough study on the relationship between physicochemical properties and toxicity needs to be conducted for more comprehensive understanding of the uptake and toxicity of MWCNTs.
Caenorhabditis elegans* ; Caenorhabditis* ; Carbon* ; Eating ; Nanotubes, Carbon*

OBJECTIVES: In this study, the effect of tube length and outer diameter (OD) size of hydroxylated-multi walled carbon nanotubes (OH-MWCNTs) on their uptake and toxicity was investigated in the nematode Caenorhabditis elegans using a functional mutant analysis. METHODS: The physicochemical properties of three different OH-MWCNTs were characterized. Uptake and toxicity were subsequently investigated on C. elegans exposed to MWCNTs with different ODs and tube lengths. RESULTS: The results of mutant analysis suggest that ingestion is the main route of MWCNTs uptake. We found that OH-MWCNTs with smaller ODs were more toxic than those with larger ODs, and OH-MWCNTs with shorter tube lengths were more toxic than longer counterparts to C. elegans. CONCLUSIONS: Overall the results suggest the aspect ratio affects the toxicity of MWCNTs in C. elegans. Further thorough study on the relationship between physicochemical properties and toxicity needs to be conducted for more comprehensive understanding of the uptake and toxicity of MWCNTs.
Caenorhabditis elegans* ; Caenorhabditis* ; Carbon* ; Eating ; Nanotubes, Carbon*

Carbon nanotube (CNT) is an important class of artificial nanomaterials with diverse potentials of nanobiomedical application. Before being introduced into bio-systems, it is necessary to explore the behavior and fate of CNTs in cells. However, limited understandings or information has been currently obtained in this realm, even some experimental results from different labs are conflicted. In this review, we focused on the location of CNTs in various cells as well as on the mechanisms of CNTs crossing the cell membranes. On the basis of data analysis shown by the current literatures, it was suggested that CNTs could enter cell's nucleus in certain conditions. Endocytosis and diffusion both exist; however, in some cases, one of them exhibited as major path, while the other one was not detectable because of the challenge resulting from the complex biological environments. The obstacles to powerful and standard characterizations of CNTs have also been discussed.
Cells ; metabolism ; Diffusion ; Endocytosis ; Nanotubes, Carbon ; chemistry

Electrodes ; Enterovirus A, Human ; isolation & purification ; Gold ; Metal Nanoparticles ; Nanotubes, Carbon

In this study, the adsorption behavior of epirubicin hydrochloride (EPI) on carboxylated single-walled carbon nanotubes (c-SWNTs) obtained by mixture acid treatment was investigated. The results indicated that the dispersion of c-SWNTs in water was obviously improved. The absorption of EPI on c-SWNTs came to equilibrium after 240 min and could be explained by pseudo-second-order model. Moreover, there were heterogeneous distribution of active sites onto c-SWNTs surface and the Freundlich isotherm model was better fit to describe the absorption precess of EPI on c-SWNTs. The absorption capacity of EPI on c-SWNTs increased obviously with the increasing pH and decreasing temperature. Compared with multi-walled carbon nanotubes, carboxylated multi-walled carbon nanotubes, SWNTs, c-SWNTs possessed higher absorption capacity for EPI. The controlled, targeted and sustained release of EPI from c-SWNTs-EPI could be instructive for the development of nano-carrier.
Adsorption ; Antibiotics, Antineoplastic ; chemistry ; Carboxylic Acids ; chemistry ; Drug Carriers ; Epirubicin ; chemistry ; Nanotubes, Carbon ; chemistry

AIMTo simulate the inhalation of the C21H27NO and C29H41NO4 molecules, the effective components of methadone and buprenorphine, into carbon nanotubes, and discuss the feasibility of the loading of methadone and buprenorphine into carbon nanotubes.

METHODSThe MM + force-field based molecular dynamics (MD) method uas used.

RESULTSThe ends-opened carbon nanotubes with diameter larger than 1 or 1.25 nm can initiatively inhale the C21H27 NO or C29H41NO4 molecule, and both two molecules have higher potential energy at the open ends of the carbon tubes than that at the middle of the tubes; the present single-walled nanotubes are very suitable for the loading of methadone and buprenorphine.

CONCLUSIONIt is possible to make sustained-release detoxification agents with methadone- or buprenorphine-loaded carbon nanotubes.

Buprenorphine ; chemistry ; Computer Simulation ; Methadone ; chemistry ; Models, Molecular ; Molecular Structure ; Nanotubes, Carbon ; chemistry ; Narcotic Antagonists ; chemistry

Electrochemical behaviors, electrochemical kinetics and electrochemical determination of sulfamethoxazole (SMZ) at both glassy carbon electrode (GCE) and multi-wall carbon nanotubes-Nafion modified glassy carbon electrode (MWCNTs-Nafion/GCE) were investigated by cyclic voltammetry (CV), chronocoulometry (CC), chronoamperometry (CA), linear scan voltammetry (LSV) and amperometric i-t curve. The experimental results showed that the electrochemical oxidation of SMZ was sluggish on GCE, but the oxidation peak current of SMZ increased significantly at MWCNTs-Nafion/GCE in comparison with that at the bare GCE, which indicated that MWCNTs-Nafion/GCE could catalyze the electrochemical oxidation of SMZ very well. The plot of oxidation peak currents versus the square roots of the scanning rates for the redox in the potential range of 10-1,000 mV x s(-1) showed a straight line, as expected for a diffusion-limited electrochemical process for SMZ electrochemical oxidation. At the bare GCE and MWCNTs-Nafion/GCE the oxidation peak current was linearly proportional to the concentration of SMZ over the concentration range 5.0 x 10(-5)-2.5 x 10(-3) mol x L(-1) and 1.0 x 10(-5)-6.0 x 10(-3) mol x L(-1). The detection limits were 1.0 x 10(-5) and 5.0 x 10(-7) mol x L(-1). The relative standard deviation was between 0.85% -1.98% and the recovery was in the range of 98%-101.2%. This MWCNTs-Nafion/GCE could be applied in SMZ electrochemical determination with satisfied results. The proposed method can be applied to the determination of SMZ in tablet samples with satisfied results.
Catalysis ; Electrochemistry ; methods ; Electrodes ; Fluorocarbon Polymers ; chemistry ; Kinetics ; Nanotubes, Carbon ; Oxidation-Reduction ; Sulfamethoxazole ; analysis ; chemistry

With the emergence of avian flu, influence A virus and other diseases, the development of rapid, real-time, label-free biological sensors has become increasingly significant at the early detection and clinical diagnoses of various diseases. Single-walled carbon nanotubes (SWNTs) have unique one-dimensional structure, special electrical properties, good biocompatibility and size compatibility, so that the SWNTs have great potential uses in the biosensor fields due to these advantages. This article reviews recent examples of carbon nanotubes field-effect transistor (CNTFET) as a label-free biosensors for detecting a variety of biological macromolecules, such as protein, enzyme, DNA, cancer, virus, carbohydrate and so on.
Animals ; Biosensing Techniques ; instrumentation ; trends ; DNA ; chemistry ; Humans ; Nanotubes, Carbon ; chemistry ; Proteins ; analysis ; Transistors, Electronic