The adsorption of biomolecules to multi-walled carbon nanotubes is influenced by both pulmonary surfactant lipids and surface chemistry

Background During production and processing of multi-walled carbon nanotubes (MWCNTs), they may be inhaled and may enter the pulmonary circulation. It is essential that interactions with involved body fluids like the pulmonary surfactant, the blood and others are investigated, particularly as these interactions could lead to coating of the tubes and may affect their chemical and physical characteristics. The aim of this study was to characterize the possible coatings of different functionalized MWCNTs in a cell free environment. Results To simulate the first contact in the lung, the tubes were coated with pulmonary surfactant and subsequently bound lipids were characterized. The further coating in the blood circulation was simulated by incubating the tubes in blood plasma. MWCNTs were amino (NH2)- and carboxyl (-COOH)-modified, in order to investigate the influence on the bound lipid and protein patterns. It was shown that surfactant lipids bind unspecifically to different functionalized MWCNTs, in contrast to the blood plasma proteins which showed characteristic binding patterns. Patterns of bound surfactant lipids were altered after a subsequent incubation in blood plasma. In addition, it was found that bound plasma protein patterns were altered when MWCNTs were previously coated with pulmonary surfactant. Conclusions A pulmonary surfactant coating and the functionalization of MWCNTs have both the potential to alter the MWCNTs blood plasma protein coating and to determine their properties and behaviour in biological systems.

Channels and transporters. Mini-symposium of the Division of Medicinal Chemistry (DMC) of the Swiss Chemical Society (SCS) at the Department of Chemistry, University of Basel, May 27, 2010

During a half-day symposium, the topic 'Channels and Transporters' was covered with five lectures, including a presentation on 'Introduction and Basics of Channels and Transporters' by Beat Ernst, lectures on structure, function and physiology of channels and transporters ('The Structural Basis for Ion Conduction and Gating in Pentameric Ligand-Gated Ion Channels' by Raimund Dutzler and 'Uptake and Efflux Transporters for Endogenous Substances and for Drugs' by Dietrich Keppler), and a case study lecture on 'Avosentan' by Werner Neidhart. The program was completed by Matthias Hediger who introduced to the audience the National Center of Competence in Research (NCCR)-TransCure in his lecture entitled 'From Transport Physiology to Identification of Therapeutic Targets'.

Retrieval simulations of the vertical profiles of water vapour and other chemical species in the Martian atmosphere using PACS

Water vapour, despite being a minor constituent in the Martian atmosphere with its precipitable amount of less than 70 pr. μm, attracts considerable attention in the scientific community because of its potential importance for past life on Mars. The partial pressure of water vapour is highly variable because of its seasonal condensation onto the polar caps and exchange with a subsurface reservoir. It is also known to drive photochemical processes: photolysis of water produces H, OH, HO2 and some other odd hydrogen compounds, which in turn destroy ozone. Consequently, the abundance of water vapour is anti-correlated with ozone abundance. The Herschel Space Observatory provides for the first time the possibility to retrieve vertical water profiles in the Martian atmosphere. Herschel will contribute to this topic with its guaranteed-time key project called "Water and related chemistry in the solar system". Observations of Mars by Heterodyne Instrument for the Far Infrared (HIFI) and Photodetector Array Camera and Spectrometer (PACS) onboard Herschel are planned in the frame of the programme. HIFI with its high spectral resolution enables accurate observations of vertically resolved H2O and temperature profiles in the Martian atmosphere. Unlike HIFI, PACS is not capable of resolving the line-shape of molecular lines. However, our present study of PACS observations for the Martian atmosphere shows that the vertical sensitivity of the PACS observations can be improved by using multiple-line observations with different line opacities. We have investigated the possibility of retrieving vertical profiles of temperature and molecular abundances of minor species including H2O in the Martian atmosphere using PACS. In this paper, we report that PACS is able to provide water vapour vertical profiles for the Martian atmosphere and we present the expected spectra for future PACS observations. We also show that the spectral resolution does not allow the retrieval of several studied minor species, such as H2O2, HCl, NO, SO2, etc.