PEG polymer brushes via the Langmuir-Schaefer technique: the transfer ratio.

The Langmuir-Schaefer technique allows horizontal transfer of monolayer films of amphiphilic molecules from an air-water interface to a hydrophobic solid substrate. Spectroscopic ellipsometry has been used to estimate the transfer ratio of Polyethylene Glycol (PEG) polymer brushes prepared by this Langmuir-Schaefer method. We measured the transfer ratio for various degrees of polymerization and surface densities at the air-water interface.

A neutron reflection study of adsorbed deuterated myoglobin layers on hydrophobic surfaces.

The structure of adsorbed globular protein layers on hydrophobic surfaces is elucidated in detail by combining the use of a fully deuterated protein, myoglobin, and the neutron reflectivity technique. The hydrophobic surfaces consist of grafted self-assembled monolayer of octadecyltrichlorosilane (OTS) and polystyrene (PS) layer on silicon substrates. Different protein concentrations ranging from 1mg/ml to 0.

Protein adsorption on poly(N-isopropylacrylamide) brushes: dependence on grafting density and chain collapse.

The protein resistance of poly(N-isopropylacrylamide) brushes grafted from silicon wafers was investigated as a function of the chain molecular weight, grafting density, and temperature. Above the lower critical solution temperature (LCST) of 32 °C, the collapse of the water-swollen chains, determined by ellipsometry, depends on the grafting density and molecular weight. Ellipsometry, radio assay, and fluorescence imaging demonstrated that, below the lower critical solution temperature, the brushes repel protein as effectively as oligoethylene oxide-terminated monolayers.

Variable-field relaxometry of iron-containing human tissues: a preliminary study.

Excess iron is found in brain nuclei from neurodegenerative patients (with Parkinson's, Alzheimer's and Huntington's diseases) and also in the liver and spleen of cirrhosis, hemochromatosis and thalassaemia patients. Ferritin, the iron-storing protein of mammals, is known to darken T(2)-weighted MR images. Understanding NMR tissue behavior may make it possible to detect those diseases, to follow their evolution and finally to establish a protocol for non-invasive measurement of an organ's iron content using MRI methods.