We use spectroscopic techniques focusing on continuous wave-Electron Spin Resonance (cw-ESR, also called Electron Paramagnetic Resonance) to answer the problems in biological and material sciences. ESR is a technique for studying chemical species that contain one or more unpaired electrons. Features of ESR currently used in our lab to inspect molecules in biological systems are as followed:

Local movements of a macromolecule, such as protein and polymer chain is important to determine conformational changes. The lineshape of ESR is sensitive to the reorientation, modulated by motion of the macromolecular chain. For proteins, a method that combines site-directed mutagenesis with a spin-label makes it possible to observe ESR signals in any specific location of proteins. The figure demonstrates the sensitivity of ESR lineshape to the local motion of a spin-label poline peptide.

Many metalloproteins contain paramagnetic metals (ESR active), such as Cu²⁺, Mn²⁺, Fe²⁺, etc. as cofactors. The aim in the early stage of the project is to characterize the presence of matal-ion in a metalloprotein.

Proteins and enzymes work with highly specific functions. Unfortunately, they are often unstable and show low activity when denatured by pH, or thermal treatment. These disadvantages can be overcome by immobilization of the enzyme onto a solid structure. When immobiliezed the protein conformation is always altered. Sensitivity of ESR to local rotational motions of proteins provides ESR as a sensitive tool to monitor proteins in confined environment. Protein immobilization on nanostructures restricts the movement of proteins and then affect their functions. We employ ESR to monitor the local motion and, moreover, the partial strctural changes of proteins could be determined.

Examples of nanomaterials are:

- Mesoporous materials: e.g., MCM41, SBA.

- Nanofibers: