Photophysical and photochemical properties of HITC indotricarbocyanine dye molecules in solutions

Concentration Increase of the Singlet-Oxygen Generation Quantum Yield by an Indotricarbocyanine Dye

“…Such behavior agreed with previous results [21] where the photophysical parameters of this dye changed only at concentrations >5•10 -3 M after adding additional KI to the solution. The identical spectral and luminescence characteristics of the cationic dye analogs with different counterions were consistent with the dissociation of these compounds into ions in polar solvents [18,19]. Changes of the photophysical properties of the iodide upon increasing the concentration in slightly polar solvents in addition to the spectral characteristics of photosensitizers with Iand ClO 4 counterions indicated that the system was nonuniform under such conditions.…”

“…It must be considered for all dye applications that part of the excitation energy during light absorption is expended on the sensitization of singletoxygen ( 1 O 2 ) formation. This process in oxygen-saturated solutions is responsible for PD photodestruction [17,18]. The effi ciency of PDs as photosensitizers depends mainly on their ability for photo-induced 1 O 2 generation [11].…”

“…The effi ciency of PDs as photosensitizers depends mainly on their ability for photo-induced 1 O 2 generation [11]. The effect of ionic equilibria on the effi ciency of 1 O 2 generation by PDs has not been suffi ciently studied despite much research on PD photophysical properties in various solvents [17][18][19][20]. Such research is important because indotricarbocyanine dyes in cancer cells are localized in regions of low dielectric permeability primarily as contact ion pairs [12,15].…”

Spectroelectrochemical and ESR investigation of free radicals derived from indotricarbocyanine dyes for photodynamic therapy

“…It should be noted that for biomedical applications, the indotricarbocyanine dye is obtained as a bromide salt to improve its solubility in aqueous media. Previously obtained results [24] hint at the ability of the photoexcited molecules of the indotricarbocyanine dye under study to sensitize generation of highly reactive bromine radicals from bromide ions thus inducing cytotoxicity in vivo. This assumption could explain retained efficiency of the dye under hypoxia.…”

“…Cytotoxicity in PDT is induced by photochemical processes. Such processes can be probed using spectroscopic techniques, such as transient absorption spectroscopy [21,24]. At the same time, studying intermediates of photochemical processes is a challenge as the species can be short-lived (<100 ps lifetime) [21].…”