Because cancer is the second leading cause of death globally, investigation of new photosensitizers for photodynamic therapy is highly desirable. In this work, different peripherally substituted subphthalocyanines (SubPcs) with either a benzocrown moiety (CE-) or a tyrosine methyl ester (Tyr-) as the axial ligand have been prepared. Target SubPcs showed high ΦΔ values, >0.50 in EtOH. Both CE- and Tyr- moieties increased substantially the hydrophilicity of the compounds (log P = 1.79-2.63, n-octanol/PBS). Uptake to cells, subcellular localization, and monitoring of the progression of cell death over time are described. Improved spectroscopic behavior of the CE- series in cell culture medium resulted in higher photodynamic activity versus that of the Tyr- series. In particular, the peripherally triethylsulfanyl SubPc-CE exhibited extraordinarily low EC50 values of 2.3 and 4.4 nM after light activation and high TC50 values of 14.49 and 5.25 μM (i.e., dark toxicity without activation) on SK-MEL-28 and HeLa cells, respectively, which rank it among the best photosensitizers ever.
It is well-known that the applicability of phthalocyanine chemiresistors suffers from long recovery time after NO2 exposure. This circumstance enforces the necessity to operate the sensors at elevated temperatures (150-200 °C), which shortens the sensor lifetime and increases its power consumption (regardless, a typical measurement period is longer than 15 min). In this paper, we propose a new method for fast and effective recovery by UV-vis illumination at a low temperature (55 °C). The method is based on short illumination following short NO2 exposure. To support and optimize the method, we investigated the effects of light in the wavelength and intensity ranges of 375-850 nm and 0.2-0.8 mW/mm2, respectively, on the rate of NO2 desorption from the phthalocyanine sensitive layer during the recovery period. This investigation was carried out for a set of phthalocyanine materials (ZnPc, CuPc, H2Pc, PbPc, and FePc) operating at slightly elevated temperatures (55-100 °C) and was further supported by the analysis of UV-vis and FTIR spectral changes. We found out that the light with the wavelength shorter than 550 nm significantly accelerates the NO2 desorption from ZnPc, CuPc, and FePc, and allows bringing the measurement period under 2 min and decreasing the sensor power consumption by 75%. Possible mechanisms of the light-stimulated desorption are discussed.
- MeSH
- isoindoly chemie účinky záření MeSH
- oxid dusičitý chemie MeSH
- světlo MeSH
- teplota MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
