Photophysical Characterization and BSA Interaction of Direct Ring Carboxy Functionalized Symmetrical squaraine Dyes

Saikiran, Maryala; Pandey, Shyam S.; Hayase, Shuzi; Kato, Tamaki

doi:10.1088/1742-6596/924/1/012006

Cited by 8 publications

(10 citation statements)

References 26 publications

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“…The use of squaraine dyes as fluorescent probes for the detection and quantification of biomolecules is well known. Recently, studies have focused on the detection of bovine serum albumin (BSA) and human serum albumin (HSA), using squaraine dyes, verifying that these dyes change their fluorescence patterns when in the presence of these proteins, showing, in most cases, a linear relationship between the fluorescence intensity emitted and the amount of protein present (29)(30)(31)(32)(33)(34). The results obtained revealed a promising future for the possible application of squaraine dyes in standardized fluorescent methods for the detection of these proteins.…”

Section: Introductionmentioning

confidence: 99%

Squaraine Dyes Derived from Indolenine and Benzo[e]indole as Potential Fluorescent Probes for HSA Detection and Antifungal Agents

Gomes

Ferreira

Boto

et al. 2022

Photochem & Photobiology

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Four squaraine dyes derived from 2,3,3-trimethylindolenine and 1,1,2-trimethyl-1H-benzo[e]indole with different combinations of barbituric groups attach to the central ring, having ester groups and alkyl chains in the nitrogen atoms of heterocyclic rings were synthesized. These dyes were fully characterized, and their photophysical behavior was studied in ethanol and phosphate-buffered solution. Absorption and emission bands between 631 and 712 nm were detected, with the formation of aggregates in aqueous media, which is typical of this class of dyes. Tests carried out with 1,3diphenylisobenzofuran allowed us to verify the ability of the dyes to produce singlet oxygen. The interaction of synthesized dyes with human serum albumin (HSA) was also evaluated, being demonstrated a linear correlation between fluorescence intensity and protein concentration. The antifungal potential of the dyes against the yeast Saccharomyces cerevisiae was evaluated using a broth microdilution assay. In order to test the photosensitizing capacity of the synthesized dyes, tests were carried out in the dark and with irradiation, using a custom-built light-emitting diode that emits close to the absorption wavelength of the studied dyes. The results showed that the interaction of dyes with HSA and the antifungal activity depends on the different structural modifications of the dyes.

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Section: Introductionmentioning

confidence: 99%

Squaraine Dyes Derived from Indolenine and Benzo[e]indole as Potential Fluorescent Probes for HSA Detection and Antifungal Agents

Gomes

Ferreira

Boto

et al. 2022

Photochem & Photobiology

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“…It can be seen from this table that the binding constants of the dyes in this study show an order higher in magnitude compared to typical squaraine dyes. 55 SQ-215 showed the highest K a among the dyes in this study. Analysis of Job's plot showed that BSA interacts with all the dyes in a 2:1 ratio.…”

Section: Interaction Of Dyes With Bsamentioning

confidence: 47%

“…The slope of the plot gave the corresponding value of the binding constant ( K a ), as summarized in Table . It can be seen from this table that the binding constants of the dyes in this study show an order higher in magnitude compared to typical squaraine dyes …”

Section: Resultsmentioning

confidence: 98%

“…Patonay and co-workers first studied the noncovalent labeling of NIR dyes with HSA . Due to its high homology with HSA in the amino acid sequences, BSA has prominently been used as a model protein to investigate the interactions between dye and protein. , It can be seen from Figure that, with the increasing concentrations of BSA, a decrease in the intensity of the SQ-27 ’s shoulder peak and an increase in the intensity of the main peak at 674 nm are observed, indicating the prevention of dye aggregation due to dye–BSA interactions. At the same time, this enhanced dye–BSA interaction led to the reappearance of a fluorescence signal at 678 nm with a tremendous increase with increasing concentrations of BSA.…”

Section: Resultsmentioning

confidence: 99%

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Photophysical Characterization and Biointeractions of NIR Squaraine Dyes for in Vitro and in Vivo Bioimaging

Mavileti,

Bila,

Utka

et al. 2023

ACS Appl. Bio Mater.

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The increasing demand for reliable near-infrared (NIR) probes exhibiting enduring fluorescence in living systems and facile compatibility with biomolecules such as peptides, antibodies or proteins is driven by the increasing use of NIR imaging in clinical diagnostics. To address this demand, a series of carboxy-functionalized unsymmetrical squaraine dyes (SQ-27, SQ-212, and SQ-215) along with non-carboxy-functionalized SQ-218 absorbing and emitting in the NIR wavelength range were designed and synthesized followed by photophysical characterization. This study focused on the impact of structural variations in the alkyl chain length, carboxy functionality positioning, and spacer chain length on dye aggregation and interaction with bovine serum albumin (BSA) as a model protein. In phosphate buffer (PB), the absorption intensity of the dyes markedly decreased accompanied by pronounced shoulders indicative of dye aggregation, and complete fluorescence quenching was seen in contrast to organic solvents. However, in the presence of BSA in PB, there was a enhancement in absorption intensity while regaining the fluorescence coupled with a remarkable increase in the intensity with increasing BSA concentrations, signifying the impact of dye−BSA interactions on preventing aggregation. Further analysis of Job's plot unveiled a 2:1 interaction ratio between BSA and all dyes, while the binding studies revealed a robust binding affinity (K a ) in the order of 10 7 /mol. SQ-212 and SQ-215 were further tested for their in vitro and in vivo imaging capabilities. Notably, SQ-212 demonstrated nonpermeability to cells, while SQ-215 exhibited easy penetration and prominent cytoplasmic localization in in vitro studies. Injection of the dyes into laboratory mice showcased their efficacy in visualization, displaying stable and intense fluorescence in tissues without toxicity, organ damage, or behavioral changes. Thus, SQ-212 and SQ-215 are promising candidates for imaging applications, holding potential for noninvasive cellular and diagnostic imaging as well as biomarker detection when coupled with specific vectors in living systems.

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“…Every resulting dye showed aggregationinduced emission and also tetraphenylethylene-functionalized dyes exhibited a larger molar extinction coefficient, and triphenylethylene-functionalized dyes exhibited a redshift λ max : 723 nm (Chua et al 2018). Another study conducted by Saikiran et al (2017) reported the synthesis and characterization of direct (-COOH) functionalized squaraine dyes subjected to their interaction with BSA. All dyes exhibited sharp and intense optical absorption mainly in the far-red region and very high molar extinction coefficient (table 1(H)).…”

Section: Squaraine Derivativesmentioning

confidence: 99%

Multifunctional materials conjugated with near-infrared fluorescent organic molecules and their targeted cancer bioimaging potentialities

Asgher¹,

Qamar²,

Sadaf³

et al. 2020

Biomed. Phys. Eng. Express

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Near-infrared fluorescent dyes based on small organic molecules are believed to have a great influence on cancer diagnosis at large and targeted cancer cell bioimaging, in particular. NIR dyes-based organic molecules have notable characteristics features, such as high tissue penetration and low tissue autofluorescence in the NIR spectral region. Cancer targeted bioimaging relies significantly on the synthesis of highly specific molecular probes with excellent stability. Recently, NIR dyes have emerged as unique fluorescent probes for cancer bioimaging. These current advancements have overcome many limitations of conventional NIR probes e.g., poor photostability and hydrophilicity, insufficient stability and low quantum yield. The further potential lies in NIR dyes or NIR dyes-coated nanocarriers conjugated with cancer-specific ligand (e.g., peptides, antibodies, proteins or other small molecules). Multifunctional NIR dyes have synthesized, which efficiently accumulate in cancer cells without requiring chemical conjugation and also these dyes have presented novel photophysical and pharmaceutical properties for in vivo imaging. This review highlights the recently developed NIR dyes with novel applications in cancer bioimaging. We believe that these novel fluorophores will enhance our understanding of cancer imaging and pave a new road in cancer diagnosis and treatment.

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Photophysical Characterization and BSA Interaction of Direct Ring Carboxy Functionalized Symmetrical squaraine Dyes

Cited by 8 publications

References 26 publications

Squaraine Dyes Derived from Indolenine and Benzo[e]indole as Potential Fluorescent Probes for HSA Detection and Antifungal Agents

Squaraine Dyes Derived from Indolenine and Benzo[e]indole as Potential Fluorescent Probes for HSA Detection and Antifungal Agents

Photophysical Characterization and Biointeractions of NIR Squaraine Dyes for in Vitro and in Vivo Bioimaging

Multifunctional materials conjugated with near-infrared fluorescent organic molecules and their targeted cancer bioimaging potentialities

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