Photoactivatable caged cyclic RGD peptide for triggering integrin binding and cell adhesion to surfaces

We report the synthesis and properties of a photoactivatable caged RGD peptide and its application for phototriggering integrin- and cell-binding to surfaces. We analysed in detail 1) the differences in the integrin-binding affinity of the caged and uncaged forms by quartz crystal microbalance (QCM) studies, 2) the efficiency and yield of the photolytic uncaging reaction, 3) the biocompatibility of the photolysis by-products and irradiation conditions, 4) the possibility of site, temporal and density control of integrin-binding and therefore human cell attachment, and 5) the possibility of in situ generation of cell patterns and cell gradients by controlling the UV exposure. These studies provide a clear picture of the potential and limitations of caged RGD for integrin-mediated cell adhesion and demonstrate the application of this approach to the control and study of cell interactions and responses.     

Asymmetric magnetization reversal of stripe-patterned exchange bias layer systems for controlled magnetic particle transport

Domain wall movement assisted transport of particles: exchange-biased samples with designed stripe-domains show strong stray fields and an asymmetric magnetization reversal. Using these characteristics superparamagnetic particles can be trapped and transported directly on the sample over large-scale areas. High particle velocities, small external fields, and automatically reduced particle clustering allow broad applicability of this transport method.     

Vibronic Transitions of Atomic Bubbles in Condensed 4He

Laser spectroscopy of atomic dopants can be used as a tool for the investigation of elementary excitations in quantum fluids and solids. Here we present results of a laser-spectroscopic study of transition-metal (Au, Cu) atoms in liquid and solid ⁴He. In particular we observe transitions of inner shell electrons that have not been studied before. Such transitions are weakly perturbed by the interaction with the helium matrix and display a characteristic structure composed of a sharp zero-phonon line and a relatively broad phonon wing.