Spectroscopic and Biological Properties of the 3-Imino-1,8-naphthalimide Derivatives as Fluorophores for Cellular Imaging

This paper presents the photophysical and biological properties of eight 3-imino-1,8-naphthalimides. The optical properties of the compounds were investigated in the solvents that differed in their polarity (dichloromethane, acetonitrile, and methanol), including three methods of sample preparation...

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Main Authors: Mateusz Korzec, Sonia Kotowicz, Katarzyna Malarz, Anna Mrozek-Wilczkiewicz
Format: Article
Language:English
Published: MDPI AG 2023-08-01
Series:Molecules
Subjects:
Online Access:https://www.mdpi.com/1420-3049/28/17/6255
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author Mateusz Korzec
Sonia Kotowicz
Katarzyna Malarz
Anna Mrozek-Wilczkiewicz
author_facet Mateusz Korzec
Sonia Kotowicz
Katarzyna Malarz
Anna Mrozek-Wilczkiewicz
author_sort Mateusz Korzec
collection DOAJ
description This paper presents the photophysical and biological properties of eight 3-imino-1,8-naphthalimides. The optical properties of the compounds were investigated in the solvents that differed in their polarity (dichloromethane, acetonitrile, and methanol), including three methods of sample preparation using different pre-dissolving solvents such as dimethyl sulfoxide or chloroform. In the course of the research, it was found that there are strong interactions between the tested compounds and DMSO, which was visible as a change in the maximum emission band (λ<sub>em</sub>) of the neat 3-imino-1,8-naphthalimides (λ<sub>em</sub> = 470–480 nm) and between the compounds and DMSO (λ<sub>em</sub> = 504–514 nm). The shift of the emission maximum that was associated with the presence of a small amount of DMSO in the sample was as much as 41 nm. In addition, the susceptibility of imines to hydrolysis in the methanol/water mixture with increasing water content and in the methanol/water mixture (<i>v</i>/<i>v</i>; 1:1) in the pH range from 1 to 12 was discussed. The studies showed that the compounds are hydrolysed in the CH<sub>3</sub>OH/H<sub>2</sub>O system in an acidic environment (pH in the range of 1 to 4). In addition, it was found that partial hydrolysis occurs in systems with an increased amount of water, and its degree may depend on the type of substituent on the imine bond. The compounds tended to quench the emission (ACQ) in the aggregated state and increase the emission related to the protonation of the imine bond. Moreover, it was found that the substituent in the imine bonds influenced a compound’s individual photophysical properties. Biological tests, including cytotoxicity studies and cellular localisation, were also performed for all of the molecules. All of the tested compounds exhibited green fluorescence in the MCF-7 cells and showed co-localisation in the mitochondria, endoplasmic reticulum, and lysosome. The obtained photophysical and biological results indicate the promising potential use of the tested compounds as cellular dyes.
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spelling doaj.art-19decf5a023f4e038968b3851e28f5932023-11-19T08:33:25ZengMDPI AGMolecules1420-30492023-08-012817625510.3390/molecules28176255Spectroscopic and Biological Properties of the 3-Imino-1,8-naphthalimide Derivatives as Fluorophores for Cellular ImagingMateusz Korzec0Sonia Kotowicz1Katarzyna Malarz2Anna Mrozek-Wilczkiewicz3Institute of Chemistry, University of Silesia in Katowice, 9 Szkolna Str., 40-006 Katowice, PolandInstitute of Chemistry, University of Silesia in Katowice, 9 Szkolna Str., 40-006 Katowice, PolandAugust Chelkowski Institute of Physics, University of Silesia in Katowice, 1A 75 Pułku Piechoty Str., 41-500 Chorzow, PolandAugust Chelkowski Institute of Physics, University of Silesia in Katowice, 1A 75 Pułku Piechoty Str., 41-500 Chorzow, PolandThis paper presents the photophysical and biological properties of eight 3-imino-1,8-naphthalimides. The optical properties of the compounds were investigated in the solvents that differed in their polarity (dichloromethane, acetonitrile, and methanol), including three methods of sample preparation using different pre-dissolving solvents such as dimethyl sulfoxide or chloroform. In the course of the research, it was found that there are strong interactions between the tested compounds and DMSO, which was visible as a change in the maximum emission band (λ<sub>em</sub>) of the neat 3-imino-1,8-naphthalimides (λ<sub>em</sub> = 470–480 nm) and between the compounds and DMSO (λ<sub>em</sub> = 504–514 nm). The shift of the emission maximum that was associated with the presence of a small amount of DMSO in the sample was as much as 41 nm. In addition, the susceptibility of imines to hydrolysis in the methanol/water mixture with increasing water content and in the methanol/water mixture (<i>v</i>/<i>v</i>; 1:1) in the pH range from 1 to 12 was discussed. The studies showed that the compounds are hydrolysed in the CH<sub>3</sub>OH/H<sub>2</sub>O system in an acidic environment (pH in the range of 1 to 4). In addition, it was found that partial hydrolysis occurs in systems with an increased amount of water, and its degree may depend on the type of substituent on the imine bond. The compounds tended to quench the emission (ACQ) in the aggregated state and increase the emission related to the protonation of the imine bond. Moreover, it was found that the substituent in the imine bonds influenced a compound’s individual photophysical properties. Biological tests, including cytotoxicity studies and cellular localisation, were also performed for all of the molecules. All of the tested compounds exhibited green fluorescence in the MCF-7 cells and showed co-localisation in the mitochondria, endoplasmic reticulum, and lysosome. The obtained photophysical and biological results indicate the promising potential use of the tested compounds as cellular dyes.https://www.mdpi.com/1420-3049/28/17/62553-imino-1,8-naphthalimidescellular imagingfluorophores
spellingShingle Mateusz Korzec
Sonia Kotowicz
Katarzyna Malarz
Anna Mrozek-Wilczkiewicz
Spectroscopic and Biological Properties of the 3-Imino-1,8-naphthalimide Derivatives as Fluorophores for Cellular Imaging
Molecules
3-imino-1,8-naphthalimides
cellular imaging
fluorophores
title Spectroscopic and Biological Properties of the 3-Imino-1,8-naphthalimide Derivatives as Fluorophores for Cellular Imaging
title_full Spectroscopic and Biological Properties of the 3-Imino-1,8-naphthalimide Derivatives as Fluorophores for Cellular Imaging
title_fullStr Spectroscopic and Biological Properties of the 3-Imino-1,8-naphthalimide Derivatives as Fluorophores for Cellular Imaging
title_full_unstemmed Spectroscopic and Biological Properties of the 3-Imino-1,8-naphthalimide Derivatives as Fluorophores for Cellular Imaging
title_short Spectroscopic and Biological Properties of the 3-Imino-1,8-naphthalimide Derivatives as Fluorophores for Cellular Imaging
title_sort spectroscopic and biological properties of the 3 imino 1 8 naphthalimide derivatives as fluorophores for cellular imaging
topic 3-imino-1,8-naphthalimides
cellular imaging
fluorophores
url https://www.mdpi.com/1420-3049/28/17/6255
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AT soniakotowicz spectroscopicandbiologicalpropertiesofthe3imino18naphthalimidederivativesasfluorophoresforcellularimaging
AT katarzynamalarz spectroscopicandbiologicalpropertiesofthe3imino18naphthalimidederivativesasfluorophoresforcellularimaging
AT annamrozekwilczkiewicz spectroscopicandbiologicalpropertiesofthe3imino18naphthalimidederivativesasfluorophoresforcellularimaging