The photo-generated closed-ring isomer of bis(5-methyl-2-phenylthiazoyl)perfluorocyclopentene shows cytotoxicity to Madin-Darby canine kidney (MDCK) cells through a caspase cascade and induces apoptosis of cells.

A closed-ring isomer of a diarylethene having a sulfone group works as the reagent for SO2 gas generation with thermal stability even at 70 °C, and it rapidly reverts to the open-ring isomer and generates the SO2 gas to induce cell death upon UV irradiation.

Photolithographic fabrication of unique microstructures composed of flexible hydrogel sheets is proposed and demonstrated by using photo-acid-generating poly(methyl methacrylate). Crosslinking of a hydroxyl-rich polymer and lifting off of the crosslinked polymer layer from the substrate are controlled respectively in an area-selective manner upon micropatterned light irradiation, and various pocket-like microstructures are fabricated resultantly.

As a powerful tool of cell screening and cell purification, we developed a novel method to kill adherent cells as cultured on a substrate by micro-projection of incoherent visible light. To kill the cells by the mild light irradiated by electrically controllable micro-projection systems currently available, we introduced the assist of the photo-responsive culture substrates functionalized with a photo-acid-generating polymer. In clear contrast to the existing laser-based methods requiring point scanning, areal micro-projection of blue light with the wavelength 436 nm killed many CHO-K1 cells at a time in the irradiated area on the substrate. The effect of the photo-generated acid was so confined that selective killing of targeted cells was achieved without critical damage to the neighboring cells. Further, we demonstrated the photo-selective killing of the adherent cells after preliminarily patterning through the photo-induced removal of cell adhesion-inhibiting polymer.

Photopharmacology has been attracting attention for the development of drugs with fewer side effects and toxicity by introducing a photoswitch structure in the drug and controlling its spatiotemporal effects by...