Preparation of DNA-modified nanoparticles and preliminary study for colorimetric SNP analysis using their selective aggregations.

DNA-modified nanospheres were prepared by anchoring amino-terminated oligodeoxynucleotides (ODNs) with carboxylates onto a colored polystyrene sphere surface through amido bonds. About 220 ODN molecules were immobilized onto a nanosphere 40 nm in diameter. Preliminary studies using the microspheres with 1 microm diameter reveal that the specificity of hybridization was retained after modification.

Determination of the three-dimensional structure of dislocations in silicon by synchrotron white X-ray topography combined with a topo-tomographic technique.

The determination of the three-dimensional dislocation structure, i.e. the configuration and nature of the dislocations, in silicon by synchrotron white X-ray topography combined with a topo-tomographic technique is demonstrated.

Colorimetric SNP analysis using oligonucleotide-modified nanoparticles.

A point mutation in the p53 gene has been detected by means of fluorescence microscopy and fluorescent resonance energy transfer (FRET) through sequence selective aggregation of DNA-modified nanoparticles, in which fluorescent dyes were impregnated.

Plane-wave X-ray topography and its application at SPring-8.

Plane-wave X-ray topography experiments were carried out at a 200 m-long beamline, BL20B2, at SPring-8. Relatively high-energy X-rays of 30 keV with an angular divergence of about 0.01 arcsec were produced by using only one collimator crystal.

Synchrotron-radiation X-ray topography of surface strain in large-diameter silicon wafers.

Using a 300 mm-wide monochromatic X-ray beam obtained at beamline BL20B2 of SPring-8, the difference in surface-strain distribution caused by various steps of silicon-wafer manufacturing, i.e. slicing, lapping, etching, grinding and polishing, was studied.