Effect of TiO₂nanoparticles on some photophysical characteristics of ketocyanine dyes

Abstract

The effect of titanium dioxide (TiO ) nanoparticles (NPs) on photophysical characteristics of 2,5-di[(E)-1-(4-dimethylaminophenyl) methylidine]-1-cyclopentanone (2,5-DMAPMC) and 2,5-di[(E)-1-(4-diethylaminophenyl)methylidine]-1-cyclopentanone (2,5-DEAPMC) ketocyanine dyes has been studied using absorption, steady-state and time-resolved fluorescence spectroscopy. The magnitudes of association constants determined based on modified absorption spectrum of dyes due to the presence of TiO NPs indicate the interaction of TiO NPs with dye molecules. The quenching of fluorescence intensity of dyes by TiO NPs is observed and it follows linear Stern-Volmer (S-V) equation. The magnitude of quenching rate parameter suggests the involvement of static quenching mechanism. The involvement of electron transfer process in reducing fluorescence intensity of dyes has been discussed. Also, varying influence of TiO NPs on two dyes is explained based on the presence of different alkyl substituent in two dyes.

Effects on human bronchial epithelial cells following low-dose chronic exposure to nanomaterials: A 6-month transformation study

“…Due to the unique physicochemical properties and increased reactivity of nanoparticles, they might interfere with photometric and fluorometric assays, potentially leading to false positive or false negative results [167,168]. Nanoparticles may enhance or quench the fluorescence signals of the dyes, adsorb assays reagents, catalyze enzymatic reactions, or they might affect the measurements due to the intrinsic fluorescence [169][170][171][172]. Several studies reported interactions between nanoparticles e.g., carbon-based materials [173], and TiO2 nanomaterials [168,172] and test systems.…”