{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:33:28Z","timestamp":1760146408946,"version":"build-2065373602"},"reference-count":37,"publisher":"MDPI AG","issue":"22","license":[{"start":{"date-parts":[[2024,11,5]],"date-time":"2024-11-05T00:00:00Z","timestamp":1730764800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"FCT\u2014Foundation for Science and Technology","award":["UIDB\/04449\/2020","UIDP\/04449\/2020","UIDB\/04033\/2020","2022.07303.PTDC\/FCT","2022.10305.PTDC\/FCT"],"award-info":[{"award-number":["UIDB\/04449\/2020","UIDP\/04449\/2020","UIDB\/04033\/2020","2022.07303.PTDC\/FCT","2022.10305.PTDC\/FCT"]}]},{"name":"HERCULES Lab","award":["UIDB\/04449\/2020","UIDP\/04449\/2020","UIDB\/04033\/2020","2022.07303.PTDC\/FCT","2022.10305.PTDC\/FCT"],"award-info":[{"award-number":["UIDB\/04449\/2020","UIDP\/04449\/2020","UIDB\/04033\/2020","2022.07303.PTDC\/FCT","2022.10305.PTDC\/FCT"]}]},{"name":"CITAB","award":["UIDB\/04449\/2020","UIDP\/04449\/2020","UIDB\/04033\/2020","2022.07303.PTDC\/FCT","2022.10305.PTDC\/FCT"],"award-info":[{"award-number":["UIDB\/04449\/2020","UIDP\/04449\/2020","UIDB\/04033\/2020","2022.07303.PTDC\/FCT","2022.10305.PTDC\/FCT"]}]},{"name":"ART3mis","award":["UIDB\/04449\/2020","UIDP\/04449\/2020","UIDB\/04033\/2020","2022.07303.PTDC\/FCT","2022.10305.PTDC\/FCT"],"award-info":[{"award-number":["UIDB\/04449\/2020","UIDP\/04449\/2020","UIDB\/04033\/2020","2022.07303.PTDC\/FCT","2022.10305.PTDC\/FCT"]}]},{"name":"Old Goa Revelations","award":["UIDB\/04449\/2020","UIDP\/04449\/2020","UIDB\/04033\/2020","2022.07303.PTDC\/FCT","2022.10305.PTDC\/FCT"],"award-info":[{"award-number":["UIDB\/04449\/2020","UIDP\/04449\/2020","UIDB\/04033\/2020","2022.07303.PTDC\/FCT","2022.10305.PTDC\/FCT"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Fluorescent labels, commonly used in highly sensitive analytical techniques for detecting and tracking biomolecules in critical fields like cellular biology, medicine, medicinal chemistry, and environmental science, are currently too expensive for routine use in standard applications, with most exhibiting small Stokes shifts. This limitation underscores the potential of 4-diethylaminobenzaldehyde derivatives as a cost-effective alternative for developing new, bright fluorophores with larger Stokes shifts. In this work, using 4-diethylaminobenzaldehyde as starting material, we developed a simple, cost-effective, and efficient synthetic strategy to produce new affordable small molecules as effective fluorescent labels for biomolecules. Density functional theory and time-dependent density functional theory calculations were also conducted to gain insights into the observed photophysical properties.<\/jats:p>","DOI":"10.3390\/molecules29225237","type":"journal-article","created":{"date-parts":[[2024,11,5]],"date-time":"2024-11-05T09:40:54Z","timestamp":1730799654000},"page":"5237","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Affordable Small Molecules as Promising Fluorescent Labels for Biomolecules"],"prefix":"10.3390","volume":"29","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2919-7295","authenticated-orcid":false,"given":"Raquel","family":"Eust\u00e1quio","sequence":"first","affiliation":[{"name":"HERCULES Laboratory, IN2PAST\u2014Associate Laboratory for Research and Innovation in Heritage, Arts, Sustainability and Territory, University of \u00c9vora, Largo Marqu\u00eas de Marialva 8, 7000-809 \u00c9vora, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4419-6431","authenticated-orcid":false,"given":"Jo\u00e3o P. Prates","family":"Ramalho","sequence":"additional","affiliation":[{"name":"HERCULES Laboratory, IN2PAST\u2014Associate Laboratory for Research and Innovation in Heritage, Arts, Sustainability and Territory, University of \u00c9vora, Largo Marqu\u00eas de Marialva 8, 7000-809 \u00c9vora, Portugal"},{"name":"Department of Chemistry and Biochemistry, School of Sciences and Technology, University of \u00c9vora, Rua Rom\u00e3o Ramalho 59, 7000-671 \u00c9vora, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8779-9828","authenticated-orcid":false,"given":"S\u00edlvia","family":"Arantes","sequence":"additional","affiliation":[{"name":"HERCULES Laboratory, IN2PAST\u2014Associate Laboratory for Research and Innovation in Heritage, Arts, Sustainability and Territory, University of \u00c9vora, Largo Marqu\u00eas de Marialva 8, 7000-809 \u00c9vora, Portugal"}]},{"given":"Ant\u00f3nio","family":"Candeias","sequence":"additional","affiliation":[{"name":"HERCULES Laboratory, IN2PAST\u2014Associate Laboratory for Research and Innovation in Heritage, Arts, Sustainability and Territory, University of \u00c9vora, Largo Marqu\u00eas de Marialva 8, 7000-809 \u00c9vora, Portugal"},{"name":"Department of Chemistry and Biochemistry, School of Sciences and Technology, University of \u00c9vora, Rua Rom\u00e3o Ramalho 59, 7000-671 \u00c9vora, Portugal"},{"name":"City U Macau Chair in Sustainable Heritage, Sino-Portugal Joint Laboratory of Cultural Heritage Conservation Science, University of \u00c9vora, Largo Marqu\u00eas de Marialva 8, 7000-809 \u00c9vora, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5409-6990","authenticated-orcid":false,"given":"Ana Teresa","family":"Caldeira","sequence":"additional","affiliation":[{"name":"HERCULES Laboratory, IN2PAST\u2014Associate Laboratory for Research and Innovation in Heritage, Arts, Sustainability and Territory, University of \u00c9vora, Largo Marqu\u00eas de Marialva 8, 7000-809 \u00c9vora, Portugal"},{"name":"Department of Chemistry and Biochemistry, School of Sciences and Technology, University of \u00c9vora, Rua Rom\u00e3o Ramalho 59, 7000-671 \u00c9vora, Portugal"},{"name":"City U Macau Chair in Sustainable Heritage, Sino-Portugal Joint Laboratory of Cultural Heritage Conservation Science, University of \u00c9vora, Largo Marqu\u00eas de Marialva 8, 7000-809 \u00c9vora, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9553-1618","authenticated-orcid":false,"given":"Ant\u00f3nio","family":"Pereira","sequence":"additional","affiliation":[{"name":"HERCULES Laboratory, IN2PAST\u2014Associate Laboratory for Research and Innovation in Heritage, Arts, Sustainability and Territory, University of \u00c9vora, Largo Marqu\u00eas de Marialva 8, 7000-809 \u00c9vora, Portugal"},{"name":"Department of Chemistry and Biochemistry, School of Sciences and Technology, University of \u00c9vora, Rua Rom\u00e3o Ramalho 59, 7000-671 \u00c9vora, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2024,11,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"4","DOI":"10.1007\/s11705-021-2041-2","article-title":"Recent advances in small molecule fluorescent probes for simultaneous imaging of two bioactive molecules in live cells and in vivo","volume":"16","author":"Zhou","year":"2022","journal-title":"Front. Chem. Sci. Eng."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"855","DOI":"10.1021\/cb500078u","article-title":"Bright Building Blocks for Chemical Biology","volume":"9","author":"Lavis","year":"2014","journal-title":"ACS Chem. Biol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1515","DOI":"10.1021\/cr960386p","article-title":"Signaling Recognition Events with Fluorescent Sensors and Switches","volume":"97","author":"Silva","year":"1997","journal-title":"Chem. Rev."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"123","DOI":"10.1023\/A:1003287101868","article-title":"Fluorescent probes for living cells","volume":"30","author":"Johnson","year":"1998","journal-title":"Histochem. J."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1807","DOI":"10.1039\/C4CS00337C","article-title":"Imaging of \u03b2-amyloid plaques by near infrared fluorescent tracers: A new frontier for chemical neuroscience","volume":"44","author":"Staderini","year":"2015","journal-title":"Chem. Soc. Rev."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"645","DOI":"10.1007\/s11307-017-1050-5","article-title":"Fluorescence Imaging for Cancer Screening and Surveillance","volume":"19","author":"Tipirneni","year":"2017","journal-title":"Imaging Biol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"122","DOI":"10.1016\/j.chembiol.2015.12.003","article-title":"A Bright Future for Precision Medicine: Advances in Fluorescent Chemical Probe Design and Their Clinical Application","volume":"23","author":"Garland","year":"2016","journal-title":"Cell Chem. Biol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"188","DOI":"10.1016\/j.jamcollsurg.2018.11.003","article-title":"Optimization of Second Window Indocyanine Green for Intraoperative Near-Infrared Imaging of Thoracic Malignancy","volume":"228","author":"Newton","year":"2019","journal-title":"J. Am. College Surg."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"2620","DOI":"10.1021\/cr900263j","article-title":"New Strategies for Fluorescent Probe Design in Medical Diagnostic Imaging","volume":"110","author":"Kobayashi","year":"2010","journal-title":"Chem. Rev."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"505","DOI":"10.2174\/138620708785204090","article-title":"Fluorescent Probes for Cellular Assays","volume":"11","author":"Hanson","year":"2008","journal-title":"Comb. Chem. High Throughput Screen."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"561","DOI":"10.1038\/nmeth.1213","article-title":"Cell-surface protein-protein interaction analysis with time-resolved FRET and snap-tag technologies: Application to GPCR oligomerization","volume":"5","author":"Maurel","year":"2008","journal-title":"Nat. Methods"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"15815","DOI":"10.1073\/pnas.0507705102","article-title":"Genetically encoded short peptide tag for versatile protein labeling by Sfp phosphopantetheinyl transferase","volume":"102","author":"Yin","year":"2005","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"142","DOI":"10.1021\/cb700248m","article-title":"Bright ideas for chemical biology","volume":"3","author":"Lavis","year":"2008","journal-title":"ACS Chem. Biol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"5747","DOI":"10.1039\/D0OB01131B","article-title":"Rational design of small molecule fluorescent probes for biological applications","volume":"18","author":"Jun","year":"2020","journal-title":"Org. Biomol. Chem."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"29051","DOI":"10.1039\/C8RA02297F","article-title":"Small-molecule fluorescent probes and their design","volume":"8","author":"Fu","year":"2018","journal-title":"RSC Adv."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"10627","DOI":"10.1002\/chem.201600581","article-title":"Rational Design of Push\u2013Pull Fluorene Dyes: Synthesis and Structure\u2013Photophysics Relationship","volume":"22","author":"Shaya","year":"2016","journal-title":"Chem. Eur. J."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"4418","DOI":"10.1021\/ol201751p","article-title":"Synthesis and Properties of a Blue Bipolar Indenofluorene Emitter Based on a D-\u03c0-A Design","volume":"13","author":"Thirion","year":"2011","journal-title":"Org. Lett."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Eust\u00e1quio, R., Ramalho, J.P.P., Caldeira, A.T., and Pereira, A. (2023). Rational Design of Cost-Effective 4-Styrylcoumarin Fluorescent Derivatives for Biomolecule Labeling. Molecules, 28.","DOI":"10.3390\/molecules28196822"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"8477","DOI":"10.1039\/D2RA00716A","article-title":"Development of new 2-piperidinium-4-styrylcoumarin derivatives with large Stokes shifts as potential fluorescent labels for biomolecules","volume":"12","author":"Ramalho","year":"2022","journal-title":"RSC Adv."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Eust\u00e1quio, R., Ramalho, J.P.P., Caldeira, A.T., and Pereira, A. (2022). New Red-Shifted 4-Styrylcoumarin Derivatives as Potential Fluorescent Labels for Biomolecule. Molecules, 27.","DOI":"10.3390\/molecules27051461"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"7017","DOI":"10.1039\/c2ra20389h","article-title":"Fluorescent labeling techniques in biomolecules: A flashback","volume":"2","author":"Sahoo","year":"2012","journal-title":"RSC Adv."},{"key":"ref_22","unstructured":"Hermanson, G.T. (2013). Bioconjugate Techniques, Elsevier. [3rd ed.]."},{"key":"ref_23","unstructured":"Johnson, I., and Spence, M. (2010). Molecular Probes\u2122 Handbook\u2014A Guide to Fluorescent Probes and Labeling Technologies, Thermo Fischer Scientific. [11th ed.]."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"482","DOI":"10.1021\/acs.analchem.8b05303","article-title":"Recent Advances in Design of Fluorescence-Based Assays for High-Throughput Screening","volume":"91","author":"Fang","year":"2019","journal-title":"Anal. Chem."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"16584","DOI":"10.1021\/jp404170w","article-title":"Molecular Design of UV\u2013vis Absorption and Emission Properties in Organic Fluorophores: Toward Larger Bathochromic Shifts, Enhanced Molar Extinction Coefficients, and Greater Stokes Shifts","volume":"117","author":"Liu","year":"2013","journal-title":"J. Phys. Chem. C"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"042004","DOI":"10.1088\/2050-6120\/3\/4\/042004","article-title":"Fluorescent dyes with large Stokes shifts for super-resolution optical microscopy of biological objects: A review","volume":"3","author":"Sednev","year":"2015","journal-title":"Methods Appl. Fluoresc."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"3118","DOI":"10.1021\/ct400337e","article-title":"On the Metric of Charge Transfer Molecular Excitations: A Simple Chemical Descriptor","volume":"9","author":"Guido","year":"2013","journal-title":"J. Chem. Theory Comput."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"2192","DOI":"10.1021\/jo202215x","article-title":"Geometry Relaxation-Induced Large Stokes Shift in Red-Emitting Borondipyrromethenes (BODIPY) and Applications in Fluorescent Thiol Probes","volume":"77","author":"Chen","year":"2012","journal-title":"J. Org. Chem."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"35840","DOI":"10.1039\/D0RA07050E","article-title":"Near infrared absorption\/emission perylenebisimide fluorophores with geometry relaxation-induced large Stokes shift","volume":"10","author":"Ma","year":"2020","journal-title":"RSC Adv."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"14","DOI":"10.1039\/df9500900014","article-title":"Characterization of electronic transitions in complex molecules","volume":"9","author":"Kasha","year":"1950","journal-title":"Discuss. Faraday Soc."},{"key":"ref_31","unstructured":"Frisch, M.J., Trucks, G.W., Schlegel, H.B., Scuseria, G.E., Robb, M.A., Cheeseman, J.R., Scalmani, G., Barone, V., Petersson, G.A., and Nakatsuji, H. (2016). Gaussian 16, Gaussian, Inc.. Revision B.01."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"215","DOI":"10.1007\/s00214-007-0310-x","article-title":"The M06 suite of density functionals for main group thermochemistry, thermochemical kinetics, noncovalent interactions, excited states, and transition elements: Two new functionals and systematic testing of four M06-class functionals and 12 other functionals","volume":"120","author":"Zhao","year":"2008","journal-title":"Theor. Chem. Acc."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"227","DOI":"10.1016\/S0065-3276(08)60416-5","article-title":"Recent Advances in the Description of Solvent Effects with the Polarizable Continuum Mode","volume":"32","author":"Amovilli","year":"1998","journal-title":"J. Adv. Quantum Chem."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"4708","DOI":"10.1063\/1.1394921","article-title":"Time-dependent density functional theory for molecules in liquid solutions","volume":"115","author":"Cossi","year":"2001","journal-title":"J. Chem. Phys."},{"key":"ref_35","unstructured":"(2024, January 04). Protocol Provided by Lumiprobe. Available online: https:\/\/www.lumiprobe.com\/protocols\/nhs-ester-labeling."},{"key":"ref_36","first-page":"41","article-title":"Labeling Fluorescence In Situ Hybridization Probes for RNA Targets","volume":"204","author":"Ramakrishnan","year":"2002","journal-title":"Methods Mol Biol."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Branco, P., Candeias, A., Caldeira, A.T., and Gonzalez-Perez, M. (2020). A simple procedure for detecting Dekkera bruxellensis in wine environment by RNA-FISH using a novel probe. Int. J. Food Microbiol., 314.","DOI":"10.1016\/j.ijfoodmicro.2019.108415"}],"container-title":["Molecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1420-3049\/29\/22\/5237\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T16:26:46Z","timestamp":1760113606000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1420-3049\/29\/22\/5237"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,11,5]]},"references-count":37,"journal-issue":{"issue":"22","published-online":{"date-parts":[[2024,11]]}},"alternative-id":["molecules29225237"],"URL":"https:\/\/doi.org\/10.3390\/molecules29225237","relation":{},"ISSN":["1420-3049"],"issn-type":[{"type":"electronic","value":"1420-3049"}],"subject":[],"published":{"date-parts":[[2024,11,5]]}}}