Control of supramolecular organizations by coordination bonding in tetrapyridylporphyrin thin films.

Coordination bonding has been employed for the first time to control molecular orientation in thin films and is demonstrated by using tetrapyridylporphyrin. Changing the central metal ion of porphyrin controls the balance of the coordination bonding and hydrogen bonding, and edge-on orientation has been realized for the first time as well as face-on orientation. The mechanism of the film structure formation is comprehensively explained based on the electron configuration of the central metal ion.

Simultaneous Analysis of Molecular Orientation and Quantity Change of Constituents in a Thin Film Using pMAIRS.

Spectral analysis using chemometrics is extensively used for quantitative chemical analysis in a mixture, but it works powerfully only when the peak intensity is solely proportional to the quantity of chemical components. In this sense, thin films on a solid substrate are not suitable for chemometric analysis, because the molecular orientation also influences the peak intensity via the surface selection rules. In the present study, this long-term analytical issue has readily been overcome by using p-polarized multiple-angle incidence resolution spectrometry (pMAIRS), which has a characteristic that the in-plane (IP) and out-of-plane (OP) vibrational spectra of a thin-film sample are obtained simultaneously in a common ordinate scale.

Second Generation of Multiple-Angle Incidence Resolution Spectrometry.

Infrared surface spectroscopic techniques commonly have long-term issues that (1) the multiple reflections of light in the substrate yield optical interference fringes in the absorption spectrum and (2) the double modulation of light at the interferometer in a Fourier transform infrared spectrometer makes the water-vapor subtraction impossible. These measurement troubles often disturb the quantitative analysis of chemical bands of the analyte thin film. Multiple-angle incidence resolution spectrometry (MAIRS) is not an exception in this matter, either.

Induction of multicellular 3-D spheroids of MCF-7 breast carcinoma cells by neutrophil-derived cathepsin G and elastase.

In tumor metastasis, multicellular aggregates of tumor cells form and disseminate into the blood or lymph vessels from the tumor mass, following the formation of tumor cell emboli in distant vessels. However, the mechanism by which aggregates form in the tumor mass is unknown. Neutrophils often exist in tumors and are considered to affect tumor development.