Photodynamic inactivation of gramicidin channels: a flash-photolysis study

Flash photolysis of caged compounds

Photolabile ‘caged’ compounds are biologically inert precursors of active molecules, which when irradiated with a pulse of light free the active species at its site of action (see Fig. 1). Speed is the principal advantage offered by these probes; photochemical reactions can be very fast, with release of the active species often complete within a millisecond. The method can thus be used to study...

Laser-flash-photolysis-spectroscopy: a nondestructive method?

Herein, we report the effect of the laser illumination during the diffuse-reflectance laser-flash-photolysis measurements on the morphological and optical properties of TiO2 powders. A grey-blue coloration of the TiO2 nanoparticles has been observed after intense laser illumination. This is explained by the formation of nonreactive trapped electrons accompanied by the release of oxygen atoms fr...

Photodynamic Inactivation of Endopathogenic Microbiota Using Curcumin- mediated Antimicrobial Photodynamic Therapy

Root canal disinfection is one of the main factors governing success of endodontic therapy. Antimicrobial photodynamic therapy (aPDT) is presented as a promising antimicrobial therapy that can eliminate microbiota present in infected root canal systems. In this study, a series of experiments investigated the effects of aPDT on cell viability and biofilm degradation ability of endopathogenic mic...

Flash photolysis and some of its applications.

Gramicidin A channels switch between stretch activation and stretch inactivation depending on bilayer thickness.

The patch clamp-liposome technique was used to examine the stretch sensitivity of a model membrane ion channel, gramicidin A, in membrane patches of different bilayer thickness. We found that small changes in phospholipid acyl chain length (i.e., PC-20 to PC-18) can switch gramicidin A from a stretch-activated to a stretch-inactivated channel. The demonstration that subnanometer changes in bila...