<i>In Vitro</i> and <i>In Silico</i> Evaluation of Indole-Bearing Squaraine Dyes as Potential Human Serum Albumin Fluorescent Probes

The quantitative determination of proteins is an important parameter in biochemistry, biotechnology and immunodiagnostics, and the importance of serum albumin in clinical diagnosis should be highlighted, given that alterations in its concentration are generally associated with certain diseases. As p...

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Main Authors: Margarida A. Sousa, Eurico Lima, Octávio Ferreira, Renato E. Boto, Paulo Almeida, Lucinda V. Reis
Format: Article
Language:English
Published: MDPI AG 2022-08-01
Series:Chemosensors
Subjects:
Online Access:https://www.mdpi.com/2227-9040/10/8/314
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author Margarida A. Sousa
Eurico Lima
Octávio Ferreira
Renato E. Boto
Paulo Almeida
Lucinda V. Reis
author_facet Margarida A. Sousa
Eurico Lima
Octávio Ferreira
Renato E. Boto
Paulo Almeida
Lucinda V. Reis
author_sort Margarida A. Sousa
collection DOAJ
description The quantitative determination of proteins is an important parameter in biochemistry, biotechnology and immunodiagnostics, and the importance of serum albumin in clinical diagnosis should be highlighted, given that alterations in its concentration are generally associated with certain diseases. As possible probes for this purpose, squaraine dyes have been arousing the interest of many researchers due to their unique properties, such as absorption in the visible spectra, moderate relative fluorescence quantum yields and increased fluorescence intensity after non-covalent binding to specific ligands. In this work, five squaraine dyes, four of which have never been reported in the literature, were characterized and evaluated <i>in vitro</i> and <i>in silico</i> concerning their potential application as fluorescent probes for human serum albumin detection. After interaction with the protein, the fluorescence intensity increased from 12 to 41 times, depending on the dye under study. High sensitivity (1.0 × 10<sup>5</sup>–5.4 × 10<sup>5</sup> nM), low detection limits (168–352 nM) and moderate quantitation limits (560–1172 nM) were obtained, proving the efficiency of the method. In addition, moderate-to-excellent selectivity was observed compared to γ-globulin proteins. Molecular docking suggests that the dyes interact more effectively with the Sudlow site I, and binding energies have been markedly higher than those of warfarin, a molecule known to bind to this site specifically.
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spelling doaj.art-6d1f376d8abc470cb896a9daa472346e2023-11-30T21:07:42ZengMDPI AGChemosensors2227-90402022-08-0110831410.3390/chemosensors10080314<i>In Vitro</i> and <i>In Silico</i> Evaluation of Indole-Bearing Squaraine Dyes as Potential Human Serum Albumin Fluorescent ProbesMargarida A. Sousa0Eurico Lima1Octávio Ferreira2Renato E. Boto3Paulo Almeida4Lucinda V. Reis5Chemistry Centre of Vila Real (CQVR), University of Trás-os-Montes and Alto Douro, Quinta de Prados, 5001-001 Vila Real, PortugalChemistry Centre of Vila Real (CQVR), University of Trás-os-Montes and Alto Douro, Quinta de Prados, 5001-001 Vila Real, PortugalHealth Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6201-001 Covilhã, PortugalHealth Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6201-001 Covilhã, PortugalHealth Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6201-001 Covilhã, PortugalChemistry Centre of Vila Real (CQVR), University of Trás-os-Montes and Alto Douro, Quinta de Prados, 5001-001 Vila Real, PortugalThe quantitative determination of proteins is an important parameter in biochemistry, biotechnology and immunodiagnostics, and the importance of serum albumin in clinical diagnosis should be highlighted, given that alterations in its concentration are generally associated with certain diseases. As possible probes for this purpose, squaraine dyes have been arousing the interest of many researchers due to their unique properties, such as absorption in the visible spectra, moderate relative fluorescence quantum yields and increased fluorescence intensity after non-covalent binding to specific ligands. In this work, five squaraine dyes, four of which have never been reported in the literature, were characterized and evaluated <i>in vitro</i> and <i>in silico</i> concerning their potential application as fluorescent probes for human serum albumin detection. After interaction with the protein, the fluorescence intensity increased from 12 to 41 times, depending on the dye under study. High sensitivity (1.0 × 10<sup>5</sup>–5.4 × 10<sup>5</sup> nM), low detection limits (168–352 nM) and moderate quantitation limits (560–1172 nM) were obtained, proving the efficiency of the method. In addition, moderate-to-excellent selectivity was observed compared to γ-globulin proteins. Molecular docking suggests that the dyes interact more effectively with the Sudlow site I, and binding energies have been markedly higher than those of warfarin, a molecule known to bind to this site specifically.https://www.mdpi.com/2227-9040/10/8/314human serum albuminsquaraine dyescomputational analysis<i>in vitro</i> studiesfluorescent probes
spellingShingle Margarida A. Sousa
Eurico Lima
Octávio Ferreira
Renato E. Boto
Paulo Almeida
Lucinda V. Reis
<i>In Vitro</i> and <i>In Silico</i> Evaluation of Indole-Bearing Squaraine Dyes as Potential Human Serum Albumin Fluorescent Probes
Chemosensors
human serum albumin
squaraine dyes
computational analysis
<i>in vitro</i> studies
fluorescent probes
title <i>In Vitro</i> and <i>In Silico</i> Evaluation of Indole-Bearing Squaraine Dyes as Potential Human Serum Albumin Fluorescent Probes
title_full <i>In Vitro</i> and <i>In Silico</i> Evaluation of Indole-Bearing Squaraine Dyes as Potential Human Serum Albumin Fluorescent Probes
title_fullStr <i>In Vitro</i> and <i>In Silico</i> Evaluation of Indole-Bearing Squaraine Dyes as Potential Human Serum Albumin Fluorescent Probes
title_full_unstemmed <i>In Vitro</i> and <i>In Silico</i> Evaluation of Indole-Bearing Squaraine Dyes as Potential Human Serum Albumin Fluorescent Probes
title_short <i>In Vitro</i> and <i>In Silico</i> Evaluation of Indole-Bearing Squaraine Dyes as Potential Human Serum Albumin Fluorescent Probes
title_sort i in vitro i and i in silico i evaluation of indole bearing squaraine dyes as potential human serum albumin fluorescent probes
topic human serum albumin
squaraine dyes
computational analysis
<i>in vitro</i> studies
fluorescent probes
url https://www.mdpi.com/2227-9040/10/8/314
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