Ayumi Hirano

DNA hybridization detection by porous silicon-based DNA microarray in conjugation with infrared microspectroscopy

A method is described for the label-free detection of DNA hybridization on porous silicon (por-Si), based upon the pairing of oligonucleotide chemistry and standard silicon nanotechnology. Por-Si with a pore diameter of approximately 30 nm was used to immobilize probe DNA. Infrared microspectroscopy was employed to monitor the hybridization of probe-DNA immobilized on pore surfaces with its complementary DNA (target-DNA). The immobilization of probe DNA on por-Si facilitates hybridization detection for a small sensing area (approximately 50×50u2002μm2) with a high detection efficiency. In this study, we fabricated a porous silicon-based DNA microarray (por-Si-microarray) using photolithographic and Si anodizing techniques. We demonstrate that DNA hybridization can be detected on a por-Si-microarray through the analysis of infrared absorption spectral profiles in the region where the vibration modes of the bases appear. This present approach demonstrates that por-Si-microarray in conjugation with infrared micr...

In situ observation of a cell adhesion and metabolism using surface infrared spectroscopy

In this study, we report on an inxa0situ monitoring system of living cultured cells using infrared absorption spectroscopy in the geometry of multiple internal reflections (MIR-IRAS). In order to observe living cultured cells, the temperature in the sample chamber of a FT-IR spectrometer was maintained at 37xa0°C and a humidified gas mixture containing 5% CO2 was introduced into the sample chamber. Human breast cell line MCF-7 cultured on Si MIR prisms were placed in the sample chamber and infrared spectra of MCF-7 cells were collected for 5xa0h. It was found that the adhesion and metabolism of MCF-7 cells could be monitored by the absorption intensity of amide-II protein band (1,545xa0cm−1) and also by the absorption intensities of CHx bands (2,700–3,100xa0cm−1). These results suggest that our system is useful for a nondestructive and non-label monitoring of cell viability. Our method based on infrared absorption spectroscopy has a potential for bioscreening application.