Please use this identifier to cite or link to this item: http://localhost:8080/xmlui/handle/123456789/1556
Title: Synthesis and characterization of near-infrared absorbing water soluble squaraines and study of their photodynamic effects in DLA live cells
Authors: Shafeekh, K M
Soumya, M S
Rahim, M A
Annie Abraham
Suresh Das
Keywords: Water soluble squaraine dyes
Bis-benzothiazolium squaraine dyes
DLA live cells
Photodynamic therapy
Issue Date: 2014
Publisher: Wiley
Citation: Photochemistry and Photobiology 90(3):585-595; May 2014
Abstract: Here, we report the synthesis, photophysical properties and photodynamic effects in DLA live cells of three water soluble squaraine dyes, viz. bisbenzothiazolium squaraine dyes SQMI and SQDI with iodine in one and both benzothiazolium units, respectively, and an unsymmetrical squaraine dye ASQI containing iodinated benzothiazolium and aniline substituents. The diiodinated SQDI showed an anomalous trend in both fluorescence and triplet quantum yields over the monoiodinated SQMI, with SQDI showing higher fluorescence and lower triplet quantum yields compared to SQMI. Nanosecond laser flash photolysis of SQDI and SQMI indicated the formation of triplet excited states with quantum yield of 0.19 and 0.26, respectively. On photoirradiation, both the SQDI and SQMI generate singlet oxygen and it was observed that both dyes undergoing oxidation reactions with the singlet oxygen generated. ASQI which exhibited a lower triplet quantum yield of 0.06 was, however, stable and did not react with the singlet oxygen generated. In vitro cytotoxicity studies of these dyes in DLA live cells were performed using Trypan blue dye exclusion method and it reflect an order of cytotoxicity of SQDI>SQMI>ASQI. Intracellular generation of the ROS was confirmed by dichlorofluorescein assay after the in vitro PDT.
URI: http://ir.niist.res.in:8080/jspui/handle/123456789/1556
ISSN: 0031-8655
Appears in Collections:2014

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