As a bio-molecular-sensor with high sensitivity using
surface-enhanced Raman scattering (SERS), we developed two dimensional
gold nano-mushroom arrays (G-NAMS). Because the heads of the gold mushrooms are closely placed over
all aspects on a surface of substrate, a lot of SERS enable spot, so called "hot spots", are formed. . By using G-NAMS,
we observed Raman signals of some bio samples. In the experiment to observe the adenine, which is one of four basis of
the gene, dissolved in PBS solution, adenine concentrations of 5 pM could be detected. FDTD simulation indicated, that
strong Raman enhancement of G-NAMS occurs due to synergistic action of the hot spots produced between metal nanoparticles, and the optical resonant effect in the alumina layer.
A high signal-to-noise ratio in a surface plasmon resonance (SPR) sensor was achieved using a monolithic prism sensor chip. To achieve this, a multi-differential detection technique that uses a wavelength-stabilized laser diode with optical feedback was developed. To achieve easy exchange of the sensor chip and high accuracy of measurement, the monolithic prism sensor chip was fabricated from plastic with low photo-elasticity by the injection molding method. The resolution of our sensor system was estimated to be ‹10-7 refractive index unit. The potential of the developed sensor is very high for biosensing.
In this presentation, we describe about the high resolution imaging of flagellar filaments of a salmonella with a diameter of 25 nm by a photon scanning tunneling microscope (PSTM). In our PSTM system, we have used a metal coated fiber probe with a nanometric dielectric protrusion fabricated by indigenous technique developed by us. By using this probe, flagellar filaments could be imaged as having a full width at half maximum of 50 nm. Obtained images strongly depended on the separation of the sample and to the probe, and the diameter of the aperture polarization of the irradiated light.