Interactions between magnetic nanoparticles and model lipid bilayers—Fourier transformed infrared spectroscopy (FTIR) studies of the molecular basis of nanotoxicity

The toxicity of nanoparticles (nanotoxicity) is often associated with their interruption of biological membranes. The effect of polymer-coated magnetic nanoparticles (with different Fe3O4 core sizes and different polymeric coatings) on a model biological membrane system of vesicles formed by dimyristoylphosphatidylcholine (DMPC) was studied. Selected magnetic nanoparticles with core sizes ranging from 3 to 13 nm (in diameter) were characterised by transmission electron microscopy. Samples with 10% DMPC and different nanoparticle concentrations were studied by attenuated total reflectance—Fourier transform infrared spectroscopy to establish the influence of nanoparticles on the phase behaviour of model phospholipid systems

A new crystalline phase of L-alpha-dipalmitoyl phosphatidylcholine monohydrate.

A new phase transition of L-alpha-dipalmitoyl phosphatidylcholine (DPPC) monohydrate from the "biaxial" phase to a crystalline phase (C phase) has been found at 71 degrees C by means of infrared attenuated total reflection (IR-ATR) spectroscopy. The transition is characterized by drastic conformational changes in the glycerophosphorylcholine moiety, which led on the one hand to an alignment of the turn near the ester group in the hydrocarbon chain at glycerol C(2) position. On the other hand a uniform conformation of the glycerophosphorylcholine moiety is found to be typical for the C phase, in contrast to nonuniform head group conformations of DPPC in other regions of the DPPC/water phase diagram investigated so far

Modification of Time-Resolved Step-Scan and Rapid-Scan FTIR Spectroscopy for Modulation Spectroscopy in the Frequency Range from Hz to kHz

this paper are more transparent and better accessible for the user and provide additional timedependent information (time domain, e.g. the time course of the absorbance during the stimulus period). 0.000 0.005 0.010 0.015 Phase lag /deg Frequency of sample modulation /Hz 1 10 100 1000 10000 45 90 135 180 22