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Biomedical subjects

Theo Rasing

Publications and source records attributed to Theo Rasing.

5 recordsLinked to original sources

LCD-based detection of enzymatic action.

By incorporating an ester-containing substrate in a self-assembled alignment layer for liquid crystal cells, the presence of a lipase (CALB) can be directly detected through its enzymatic action on the alignment layer, without the need for fluorescent labelling or enzyme assays.

Biosensing Techniques↗

Tunable command layers for liquid crystal alignment.

A simple method for the construction of a stable, tunable, self-assembled command layer for liquid crystal display purposes is described. A pyridine-functionalized oligosiloxane spontaneously forms an anisotropic, grooved surface on indium-tin-oxide, enabling it to align liquid crystalline molecules. The pyridine functions act as seeds for the epitaxial growth of stacks of highly ordered zinc phthalocyanines, the height of which can be controlled. These stacks increase the interaction between the surface and the liquid crystalline matrix by amplifying the surface ordering into the liquid crystal bulk. By varying the height of the stacks, direct control over the properties of the liquid crystal domains is achieved. These properties can be further tuned by adding to the liquid crystal, micro- and nanomolar concentrations of nitrogen-containing compounds, which are capable of interacting with and dissolving the stacks. The procedures we describe offer possibilities to use such tunable systems in LCD-based sensor devices as well as in solar-cell applications.

Journal Article↗

Femtosecond photomagnetic switching of spins in ferrimagnetic garnet films.

We demonstrate that intense laser pulses can be used to directly control the spins in ferrimagnetic garnet films. Through an ultrafast and nonthermal photomagnetic effect the magnetocrystalline anisotropy is modified to create a new long-lived equilibrium orientation for the magnetization. Simultaneously, the magnetization is rotated into this new state by precession in a strong transient optically generated magnetic field. All take place within the 100 fs duration of a single laser pulse, thus demonstrating the feasibility of photomagnetic switching on the femtosecond time scale.

Journal Article↗

Novel alignment technique for LCD-biosensors.

The directional drying of a low-salt Tris-EDTA (TE)-buffer to give an alignment layer offers a simple, one-step, non-contact procedure for the construction of parallel liquid crystal displays (LCDs), which can be used to amplify the presence of DNA to scales visible to the naked eye, opening up possibilities for easy detection of bio recognition events.

Biosensing Techniques↗