Hydrophobic double walled carbon nanotubes interaction with phopholipidic model membranes: 1H-, 2H-, 31P NMR and ESR study

The interactions of carbon nanotubes synthesized by catalytic chemical vapour deposition with phospholipidic bilayers, mimicking biological membranes, have been investigated using solid state 31P- and 2H NMR, 1H- and 31P NMR in liquids and ESR studies. It was found that carbon nanotubes can integrate the bilayer, depending on the overall cohesion of the membrane used. Whereas no direct interaction can be observed in small unilamellar vesicles or directly in the presence of short-chained phospholipids, carbon nanotubes incorporate into the membrane of multibilayers. The result is a significant 2–3 K lowering of the transition temperature in multibilayers of dimyristoyl lecithins, which is more markedly associated with increased fluidity in the most superficial part of the membrane below the transition temperature (292–300 K range). However, no ionophoric property was found on large unilamellar vesicles

Carbon nanotubes induce inflammation but decrease the production of reactive oxygen species in lung

With the rapid spread of carbon nanotubes (CNTs) applications, the respiratory toxicity of these compounds has attracted the attention of many scientists. Several studies have reported that after lung administration, CNTs could induce granuloma, fibrosis, or inflammation. By comparison with the mechanisms involved with other toxic particles such as asbestos, this effect could be attributed to an increase of oxidative stress. The aim of the present work was to test this hypothesis in vivo. Mice were intranasally instilled with 1.5 mg/kg of double walled carbon nanotubes (DWCNTs). Six, 24, or 48 h after administration, inflammation and localisation of DWCNTs in lungs were microscopically observed. Local oxidative perturbations were investigated using ESR spin trapping experiments, and systemic inflammation was assessed by measuring the plasma concentration of cytokines TNF-α, IL-1α, IL-1β, IL-6, IGF-1, Leptin, G-CSF, and VEGF. Examination of lungs and the elevation of proinflammatory cytokines in the plasma (Leptin and IL-6 at 6 h) confirmed the induction of an inflammatory reaction. This inflammatory reaction was accompanied by a decrease in the local oxidative stress. This effect could be attributed to the scavenger capability of pure CNTs

Biological effects of double-walled carbon nanotubes on the innate immune system: An in vitro study on THP-1 human monocytes

DWCNTs have numerous industrial and biomedical applications and several studies reported that they could act as immunomodulator systems. The immune system is the first line of defence of the human body when exposed to particulate matter. In order to investigate DWCNTs’ role on innate immunity, we used THP-1 monocytic cells for the purpose of this study. We showed that DWCNTs were not cytotoxic until 6 h, 24 h, 48 h and 72 h of incubation with THP-1 monocytic cells (concentrations tested from 10 to 50 μg/mL). From 6 h to 72 h of incubation of THP-1 cells with DWCNTs, we measured a significant increase of the baseline cell index using xCELLigence® technology showing cell adhesion. After 24 h of exposure, DWCNTs agglomerates were localized in THP-1 monocyte cytoplasm and cell adhesion was observed simultaneously with a significant increase in the expression of CD11b and CD14 cell surface proteins. Pro-inflammatory cytokine secretion (IL-1β, IL-6, IL-8, TNF-α and IL-10) was also measured in supernatants after 6 h or 24 h of exposure to DWCNTs. This pro-inflammatory response was increased in THP-1 monocytic cells pre-treated with LPS. Altogether, our data indicate that DWCNTs induce an increased pro-inflammatory response of THP-1 monocytes and seem to modulate cell surface protein expression confirming that DWCNTs could act as stimulators of innate immunity

Chronic Electromagnetic Exposure at Occupational Safety Level Does Not Affect the Metabolic Profile nor Cornea Healing after LASIK Surgery

LASIK eye surgery has become a very common practice for myopic people, especially those in the military. Sometimes undertaken by people who need to keep a specific medical aptitude, this surgery could be performed in secret from the hierarchy and from the institute medical staff. However, even though the eyes have been previously described as one of the most sensitive organs to electromagnetic fields in the human body, no data exist on the potential deleterious effects of electromagnetic fields on the healing eye. The consequences of chronic long-lasting radar exposures at power density, in accordance with the occupational safety standards (9.71 GHz, 50 W/m2), were investigated on cornea healing. The metabolic and clinical statuses after experimental LASIK keratotomy were assessed on the different eye segments in a New Zealand rabbit model. The analysis methods were performed after 5 months of exposure (1 hour/day, 3 times/week). Neither clinical or histological examinations, nor experimental data, such as light scattering, 1H-NMR HRMAS metabolomics, 13C-NMR spectra of lipidic extracts, and antioxidant status, evidenced significant modifications. It was concluded that withdrawing the medical aptitude of people working in electromagnetic field environments (i.e., radar operators in the navy) after eye surgery was not justified

Etude par RMMN des interactions drogues-membranes. Application aux molecules d'Ajoene, d'amphotericine B et aux glucosyl phospholipides de nucleotides

SIGLEINIST T 70810 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Synthèse et étude des anhydro-cyclodextrines : application à la décontamination en milieu biologique

Les per anhydro a-cyclodextrines possèdent in vivo et in vitro des propriétés complexantes vis à vis de cations. Plus particulièrement ces molécules sélectives possèdent une forte affinité relative pour les cations toxiques par rapport aux cations physiologiques (Na+, Ca2+, K+). Dans le but d'utiliser ces molécules poir la décontamination en milieu biologique, plusieurs dérivés alkylés sont préparés par substitution en position C-2 et leurs propriétés complexantes sont étudiées par RMN-1H.Les propriétés de tension superficielle, la RMN-1H et la formation de gel en phase mixte des per anhydro cyclodextrines sont liées au logP, et suggèrent fortement des interactions avec les membranes biologiques. Les effets sur les membranes sont étudiés par la techique BIAcore, la RMN-31P et -2H.GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF

Effets non thermiques des champs de radiofréquences sur le système nerveux central (étude multiparamétrique réalisée sur le rat vigile)

De nombreuses craintes sont aujourd'hui formulées quant à l'innocuité des champs de radiofréquences sur la santé. Parmi celles-ci des perturbations de la neurophysiologie et plus spécifiquement du système cholinergique central ont été évoquées. Un modèle d'étude multiparamétrique a été développé chez le rat vigile présentant à la fois un aspect électrophysiologique, neurochimique obtenu par microdialyse, comportemental par quantification des états de vigilance et thermophysiologique par le suivi de la température corporelle. Lors de l'exposition à un champ électromagnétique de 1,8 GHz ou 2,45 GHz pour des puissances athermiques, aucun effet significatif n'a pu être mis en évidence sur la neurophysiologie. Parallèlement à cette étude, une étude de la composition lipidique du tissu cérébral et une étude de ses métabolites ont été réalisées par spectroscopie RMN. Ces études également n'ont pas montré d'effets des ondes électromagnétiques.GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF

À la frontière onde-lumière

Grâce aux technologies THz (térahertz), il est d’ores et déjà possible de fabriquer des systèmes d’imagerie et il est indéniable que l’arrivée prochaine de sources facilement transportables va révolutionner les techniques de détection à distance. Dans le domaine de la santé, l’apport de cette technologie conduit à un degré de finesse inégalé jusqu’à maintenant dans l’analyse de molécules. Les applications biologiques et médicales, notamment en dentisterie et en dermatologie, sont en cours de développement. Cependant, il ne faut pas pour autant négliger l’étude des répercussions sanitaires des ondes THz ; un champ d’investigation est ainsi ouvert et les premiers résultats dans ce domaine sont maintenant disponibles