Probing tricarbocyanine dyes for targeted delivery of anthracyclines

Heptamethine carbocyanine dyes possess bright fluorescence in the near IR range and affinity to cancer cells. Thus, these dyes could be utilized as fluorescent labels and vectors for drug delivery in their covalent conjugates with cytotoxic compounds. In this work we synthesized four drug-dye conjugates of tricarbocyanine dyes with anthracycline drug daunorubicin using a CuAAC reaction. Conjugates with hydrophobic dyes possess submicromolar cytotoxicity. Fluorescent imaging revealed significant accumulation of the conjugates in mitochondria, suggesting an enhancement of an additional mechanism of anthracycline cytotoxicity – generation of ROS. The hypothesis was supported by significant reduction of activity of the conjugates in presence of an antioxidant compound.

RNA-targeting low-molecular-weight fluorophores for nucleoli staining: synthesis, in silico modelling and cellular imaging

Herein we present our work on the synthesis, investigation on photophysical properties, interactions with nucleic acids, molecular docking, and imaging application of three carbocyanine dyes. Described low-molecular-weight compounds were found...

A pH-Adjustable Tissue Clearing Solution That Preserves Lipid Ultrastructures: Suitable Tissue Clearing Method for DDS Evaluation

Visualizing biological events and states to resolve biological questions is challenging. Tissue clearing permits three-dimensional multicolor imaging. Here, we describe a pH-adjustable tissue clearing solution, Seebest (SEE Biological Events and States in Tissues), which preserves lipid ultrastructures at an electron microscopy level. Adoption of polyethylenimine was required for a wide pH range adjustment of the tissue clearing solution. The combination of polyethylenimine and urea had a good tissue clearing ability for multiple tissues within several hours. Blood vessels stained with lipophilic carbocyanine dyes were deeply visible using the solution. Adjusting the pH of the solution was important to maximize the fluorescent intensity and suppress dye leakage during tissue clearing. The spatial distribution of doxorubicin and oxidative stress were observable using the solution. Moreover, spatial distribution of liposomes in the liver was visualized. Hence, the Seebest solution provides pH-adjustable, rapid, sufficient tissue clearing, while preserving lipid ultrastructures, which is suitable for drug delivery system evaluations.

DNA Photocleavage in the Near-Infrared Wavelength Range by 2-Quinolinium Dicarbocyanine Dyes

Here, we report the syntheses of two pentamethine cyanine dyes containing quinolinium rings and substituted with either hydrogen (3) or bromine (4) at the meso carbon. The electron withdrawing bromine atom stabilizes dye 4 in aqueous buffer, allowing complex formation to occur between the dye and double-helical DNA. UV–visible, CD, and fluorescence spectra recorded at low DNA concentrations suggest that dye 4 initially binds to the DNA as a high-order aggregate. As the ratio of DNA to dye is increased, the aggregate is converted to monomeric and other low-order dye forms that interact with DNA in a non-intercalative fashion. The brominated dye 4 is relatively unreactive in the dark, but, under 707–759 nm illumination, generates hydroxyl radicals that cleave DNA in high yield (pH 7.0, 22 °C). Dye 4 is also taken up by ES2 ovarian carcinoma cells, where it is non-toxic under dark conditions. Upon irradiation of the ES2 cells at 694 nm, the brominated cyanine reduces cell viability from 100 ± 10% to 14 ± 1%. Our results suggest that 2-quinolinium-based carbocyanine dyes equipped with stabilizing electron withdrawing groups may have the potential to serve as sensitizing agents in long-wavelength phototherapeutic applications.

Synthesis of different classes of five/six membered heterocyclic cyanine dyes: A review

In this paper, synthesis of different classes of five/six membered heterocyclic cyanine dyes has been reviewed. In this paper review detailed synthesis steps were represented via equations. The synthesis covers, monomethine cyanine dyes (simple cyanine dyes), dimethine cyanine dyes, trimethine cyanine dyes (carbocyanine dyes), styryl cyanine dyes (hemicyanine dyes), aza-styryl cyanine dyes (aza-hemicyanine dyes and/or aza-cyanine dyes), merocyanine dyes (acyclic merocyanine dyes and cyclic merocyanine dyes) and apocyanine dyes. Besides, in the introduction section of this review paper some light is focused on the uses, applications and properties of cyanine dyes. This review paper is informative, useful and very readable for synthetic dye chemists, researchers and students who look for the different methods in the synthesis and preparation of various classes of five/six membered heterocyclic cyanine dyes with special emphasize in the field of heterocyclic and/or cyanine dyes chemistry. This specific type of collective review in the synthesis of different classes of only five/six membered heterocyclic cyanine dyes has been paid little attention and has great importance in the chemistry literature.