AFM imaging of RGD presenting synthetic extracellular matrix using gold nanoparticles

Several high-resolution imaging techniques such as FESEM, TEM and AFM are compared with respect to their application on alginate hydrogels, a widely used polysaccharide biomaterial. A new AFM method applicable to RGD peptides covalently conjugated to alginate hydrogels is described. High-resolution images of RGD adhesion ligand distribution were obtained by labeling biotinylated RGD peptides with streptavidin-labeled gold nanoparticles. This method may broadly provide a useful tool for sECM characterization and design for tissue regeneration strategies.     

Spin-induced forbidden evanescent states in III-V semiconductors

Within the band gap of a semiconductor no electronic propagating states are allowed, but there exist evanescent states which govern charge transport such as tunneling. In this Letter, we address the issue of their spin dependence in III-V semiconductors. Taking into account the spin-orbit interaction, we treat the problem using a k . p 14 x 14 Hamiltonian that we numerically compute for GaAs. Our results show that the removed spin degeneracy in the band gap can lead to giant energy splittings and induces forbidden zones in space where evanescent states are suppressed.     

Electric-dipole increase in NMR intensity in mixed-valence complexes

The possibility of a considerable increase in NMR intensity has been shown for absorption on mixed-valence 3d ions in magnetically ordered crystals. This effect is determined by the high intensity of electric dipole transitions between the ground and low excited levels of a mixed-valence complex, as well as by the existence of the unfrozen orbital angular momentum in such complexes, which mixes nuclear and electron states.