Nanotubes, Carbon ; adverse effects ; chemistry

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*

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

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

Carbon nanotubes, a new member of the carbon material family, can be considered as graphite sheets rolled-up into cylinders with diameters ranging in the nanometer scale. In recent years, carbon nanotubes have attracted intensive interests because of their unique nanostructures and outstanding mechanical, electrical and magnetic properties. In this paper, the structures and basic features of carbon nanotubes were described in brief. The research advances in the carbon nanotubes on the specific recognition of biomolecules by surface modification and functionalization, in the enhancement to cell growth as culture scaffolds in vitro, and in the improvement of biocompatibility for implantable biomedical material were reviewed. Also comments were made on their potential applications in biomedical sensor and biomedical microelectrics.
Biocompatible Materials ; chemistry ; Biomedical Engineering ; trends ; Nanotechnology ; methods ; trends ; Nanotubes, Carbon ; chemistry

In this paper, the new carbon nanotube modified glassy carbon electrode (F-CNTs/GCE) was prepared to establish a new method for studying the molecular interaction mechanism between baicalin metal complexes (BMC) and bovine serum album (BSA), and the principle of this method was discussed deeply. Under the physiological condition, the thermodynamics and kinetics properties of interaction between BMC and BSA were studied by cyclic voltammetry (CV) to inference their molecular effective mechanism. The results show that the presence of F-CNTs can accelerate the electron transfer, and better response signal was showed in the BMC/BMC-BSA system. The detection of interaction of BMC-BSA used new method show that BMC-BSA generates stable thermodynamically non-covalent compounds, and the obtained average binding sites of BMC-BSA were 1.7; the number of electron transfer in BMC/BMC-BSA reaction process was 2, and non electroactive supramolecular compounds of BMC-BSA were generated by this interacting reaction. The relevant research work provides a new way to study the molecular mechanism for the interaction of drugs with protein, and with a certain reference value for discussion on the non covalent interactions.
Animals ; Cattle ; Coordination Complexes ; chemistry ; Electrodes ; Flavonoids ; chemistry ; Kinetics ; Nanotubes, Carbon ; Serum Albumin, Bovine ; chemistry ; Thermodynamics

Research and development of new drug carriers are crucial to the research of drugs. Due to their unique hollow structure and nano-diameter, carbon nanotubes (CNTs) can be used as drug carriers. Functionalization of CNTs with peptides, proteins, nucleic acids or even drug molecules, the so obtained functionalized CNTs can be used as carriers to deliver bioactive molecules into cells without causing any toxicity. The research progress of CNTs as drug carriers in recent years is summarized, and the CNTs' cytotoxicity and their ability to penetrate cells are discussed, and the methods of functionalizing carbon nanotubes are also mentioned in the paper. Along with the advancement of CNTs in drug carriers system, the relationship between the way to functionalize CNTs and the so obtained modified CNTs' ability to penetrate into cells, including the effect of dimension, should be further studied. Preparation of functionalized CNTs with high solubility and low toxicity as drug carriers will be the main research areas in the near future.
Animals ; Biocompatible Materials ; Drug Carriers ; chemistry ; Drug Design ; Genetic Vectors ; Humans ; Nanotubes, Carbon ; chemistry ; Solubility

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