{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,5]],"date-time":"2026-03-05T05:42:40Z","timestamp":1772689360169,"version":"3.50.1"},"reference-count":79,"publisher":"MDPI AG","issue":"24","license":[{"start":{"date-parts":[[2019,12,11]],"date-time":"2019-12-11T00:00:00Z","timestamp":1576022400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["UID\/AGR\/04033\/2019 (CITAB)"],"award-info":[{"award-number":["UID\/AGR\/04033\/2019 (CITAB)"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["UID\/QUI\/UI0616\/2019 (CQ-VR)"],"award-info":[{"award-number":["UID\/QUI\/UI0616\/2019 (CQ-VR)"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["UID\/NAN\/50024\/2019"],"award-info":[{"award-number":["UID\/NAN\/50024\/2019"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["M-ERA-NET\/0002\/2015"],"award-info":[{"award-number":["M-ERA-NET\/0002\/2015"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"name":"European Investment Funds by FEDER\/COMPETE\/POCI","award":["POCI-01-0145-FEDER-006958 (CITAB)"],"award-info":[{"award-number":["POCI-01-0145-FEDER-006958 (CITAB)"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Applied Sciences"],"abstract":"<jats:p>The search to replace conventional cancer treatment therapies, such as chemotherapy, radiotherapy and surgery has led over the last ten years, to a substantial effort in the development of several classes of photodynamic therapy photosensitizers with desired photophysicochemical and photobiological properties. Herein we report the synthesis of 6-iodoquinoline- and benzothiazole-based unsymmetrical squaraine cyanine dyes functionalized with amine groups located in the four-membered central ring. Their photodegradation and singlet oxygen production ability, as well as their in vitro photocytotoxicity against Caco-2 and HepG2 cell lines using a 630.8 \u00b1 0.8 nm centered light-emitting diode system, were also investigated. All photosensitizer candidates displayed strong absorption within the tissue transparency spectral region (650\u2013850 nm). The synthesized dyes were found to have moderate light stability. The potential of these compounds is evidenced by their cytotoxic activity against both tumor cell lines, highlighting the zwitterionic unsubstituted dye, which showed more intense photodynamic activity. Although the singlet oxygen quantum yields of these iodinated derivatives are considered low, it could be concluded that their introduction into the quinoline heterocycle was highly advantageous as it played a role in increasing selective cytotoxicity in the presence of light. Thus, the novel synthesized dyes present photophysicochemical and in vitro photobiological properties that make them excellent photosensitizer candidates for photodynamic therapy.<\/jats:p>","DOI":"10.3390\/app9245414","type":"journal-article","created":{"date-parts":[[2019,12,12]],"date-time":"2019-12-12T03:20:16Z","timestamp":1576120816000},"page":"5414","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["Photophysicochemical Properties and In Vitro Phototherapeutic Effects of Iodoquinoline- and Benzothiazole-Derived Unsymmetrical Squaraine Cyanine Dyes"],"prefix":"10.3390","volume":"9","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8165-3326","authenticated-orcid":false,"given":"Sofia","family":"Fri\u00e3es","sequence":"first","affiliation":[{"name":"Chemistry Centre of Vila Real (CQ-VR), University of Tr\u00e1s-os-Montes and Alto Douro, Quinta de Prados, 5001-801 Vila Real, Portugal"},{"name":"Centre for Research and Technology of Agro-Environmental and Biological Sciences (CITAB-UTAD), University of Tr\u00e1s-os-Montes and Alto Douro, Quinta de Prados, 5001-801 Vila Real, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9402-8949","authenticated-orcid":false,"given":"Eurico","family":"Lima","sequence":"additional","affiliation":[{"name":"Chemistry Centre of Vila Real (CQ-VR), University of Tr\u00e1s-os-Montes and Alto Douro, Quinta de Prados, 5001-801 Vila Real, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7256-2622","authenticated-orcid":false,"given":"Renato E.","family":"Boto","sequence":"additional","affiliation":[{"name":"Health Sciences Research Centre (CICS-UBI), University of Beira Interior, Av. Infante D. Henrique, 6201-001 Covilh\u00e3, Portugal"}]},{"given":"Diana","family":"Ferreira","sequence":"additional","affiliation":[{"name":"Centro de Qu\u00edmica-F\u00edsica Molecular (CQFM), Institute for Nanosciences and Nanotechnology (IN) and Institute of Bioengineering and Biosciences (iBB), Higher Technical Institute, University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon, Portugal"}]},{"given":"Jos\u00e9 R.","family":"Fernandes","sequence":"additional","affiliation":[{"name":"Chemistry Centre of Vila Real (CQ-VR), University of Tr\u00e1s-os-Montes and Alto Douro, Quinta de Prados, 5001-801 Vila Real, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1903-5815","authenticated-orcid":false,"given":"Luis F. V.","family":"Ferreira","sequence":"additional","affiliation":[{"name":"Centro de Qu\u00edmica-F\u00edsica Molecular (CQFM), Institute for Nanosciences and Nanotechnology (IN) and Institute of Bioengineering and Biosciences (iBB), Higher Technical Institute, University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7524-9914","authenticated-orcid":false,"given":"Am\u00e9lia M.","family":"Silva","sequence":"additional","affiliation":[{"name":"Centre for Research and Technology of Agro-Environmental and Biological Sciences (CITAB-UTAD), University of Tr\u00e1s-os-Montes and Alto Douro, Quinta de Prados, 5001-801 Vila Real, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5654-9359","authenticated-orcid":false,"given":"Lucinda V.","family":"Reis","sequence":"additional","affiliation":[{"name":"Chemistry Centre of Vila Real (CQ-VR), University of Tr\u00e1s-os-Montes and Alto Douro, Quinta de Prados, 5001-801 Vila Real, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2019,12,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"3480","DOI":"10.1021\/ja01522a083","article-title":"Diketocyclobutenediol","volume":"81","author":"Cohen","year":"1959","journal-title":"J. Am. Chem. Soc."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"4825","DOI":"10.1063\/1.434686","article-title":"The molecular and crystal structure of squaric acid (3,4-dihydroxy-3-cyclobutene-1,2-dione) at 121 \u00b0C: A neutron diffraction study","volume":"67","author":"Hollander","year":"1977","journal-title":"J. Chem. Phys."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"2580","DOI":"10.1021\/ja00900a011","article-title":"New Aromatic Anions. IV. Vibrational Spectra and Force Constants for C4O4\u22122 and C5O5\u22122","volume":"85","author":"Ito","year":"1963","journal-title":"J. Am. Chem. Soc."},{"key":"ref_4","first-page":"1617","article-title":"New Synthetic Approach to Aminosquarylium Cyanine Dyes","volume":"2002","author":"Reis","year":"2002","journal-title":"Synlett"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"197","DOI":"10.1016\/j.dyepig.2008.10.001","article-title":"The synthesis and characterization of novel, aza-substituted squarylium cyanine dyes","volume":"81","author":"Reis","year":"2009","journal-title":"Dyes Pigment."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"238","DOI":"10.1016\/j.dyepig.2015.05.016","article-title":"Molecular design of near infrared polymethine dyes: A review","volume":"121","author":"Bricks","year":"2015","journal-title":"Dyes Pigment."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"84","DOI":"10.1016\/j.jphotochemrev.2017.03.001","article-title":"Squaraine dyes: The hierarchical synthesis and its application in optical detection","volume":"31","author":"Xia","year":"2017","journal-title":"J. Photochem. Photobiol. C Photochem. Rev."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"911","DOI":"10.1039\/C1OB06588B","article-title":"Squaraine dyes in PDT: From basic design to In Vivo demonstration","volume":"10","author":"Avirah","year":"2012","journal-title":"Org. Biomol. Chem."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"783","DOI":"10.1111\/j.1751-1097.1997.tb01925.x","article-title":"Halogenated Squaraine Dyes as Potential Photochemotherapeutic Agents. Synthesis and Study of Photophysical Properties and Quantum Efficiencies of Singlet Oxygen Generation","volume":"65","author":"Ramaiah","year":"1997","journal-title":"Photochem. Photobiol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"694","DOI":"10.1002\/anie.196506941","article-title":"Cyclotrimethine Dyes Derived from Squaric Acid","volume":"4","author":"Treibs","year":"1965","journal-title":"Angew. Chem. Int. Ed. Engl."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1155\/2009\/581068","article-title":"Squaraine Planar-Heterojunction Solar Cells","volume":"2009","author":"Fan","year":"2009","journal-title":"Int. J. Photoenergy"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"129","DOI":"10.2533\/chimia.2013.129","article-title":"Near-infrared Sensitization in Dye-sensitized Solar Cells","volume":"67","author":"Park","year":"2013","journal-title":"CHIMIA Int. J. Chem."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1016\/0143-7208(92)80038-O","article-title":"Squaraine chemistry. Synthesis and characterization of squaraine dyes having self-organizing properties","volume":"20","author":"Law","year":"1992","journal-title":"Dyes Pigment."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"449","DOI":"10.1021\/cr00017a020","article-title":"Organic photoconductive materials: Recent trends and developments","volume":"93","author":"Law","year":"1993","journal-title":"Chem. Rev."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"457","DOI":"10.1016\/j.dyepig.2017.02.024","article-title":"Application of benz [c,d] indolenine-based unsymmetrical squaraine dyes to near-infrared dye-sensitized solar cells","volume":"141","author":"Matsui","year":"2017","journal-title":"Dyes Pigment."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Zhu, Y., Liu, J., Zhao, J., Li, Y., Qiao, B., Song, D., Huang, Y., Xu, Z., Zhao, S., and Xu, X. (2018). Improving the Charge Carrier Transport and Suppressing Recombination of Soluble Squaraine-Based Solar Cells via Parallel-Like Structure. Materials, 11.","DOI":"10.3390\/ma11050759"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"88","DOI":"10.1016\/j.snb.2019.04.138","article-title":"Squaraine-hydrazine adducts for fast and colorimetric detection of aldehydes in aqueous media","volume":"292","author":"Liu","year":"2019","journal-title":"Sens. Actuators B Chem."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"519","DOI":"10.1016\/j.snb.2015.01.008","article-title":"A highly selective fluorescent chemosensor for Hg2+ based on a squaraine\u2013bis(rhodamine-B) derivative: Part II","volume":"210","author":"Lee","year":"2015","journal-title":"Sens. Actuators B Chem."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"605","DOI":"10.1016\/j.tet.2005.10.012","article-title":"A squaraine-based chemosensor for Hg2+ and Pb2+","volume":"62","author":"Basheer","year":"2006","journal-title":"Tetrahedron"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"847","DOI":"10.1016\/j.snb.2013.07.073","article-title":"Synthesis of near-infrared absorbing pyrylium-squaraine dye for selective detection of Hg2+","volume":"188","author":"Kim","year":"2013","journal-title":"Sens. Actuators B Chem."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"7063","DOI":"10.1021\/ac501619v","article-title":"Dicyanomethylene-Functionalized Squaraine as a Highly Selective Probe for Parallel G-Quadruplexes","volume":"86","author":"Jin","year":"2014","journal-title":"Anal. Chem."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"120","DOI":"10.1016\/j.dyepig.2017.07.070","article-title":"Synthesis, characterization and protein-association of dicyanomethylene squaraine dyes","volume":"147","author":"Martins","year":"2017","journal-title":"Dyes Pigment."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1016\/j.dyepig.2010.11.005","article-title":"Aza-substituted squaraines for the fluorescent detection of albumins","volume":"90","author":"Volkova","year":"2011","journal-title":"Dyes Pigment."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"98","DOI":"10.1016\/j.dyepig.2019.04.007","article-title":"Synthesis and In Vitro evaluation of the antitumoral phototherapeutic potential of squaraine cyanine dyes derived from indolenine","volume":"167","author":"Lima","year":"2019","journal-title":"Dyes Pigment."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"3803","DOI":"10.1016\/j.bmc.2017.05.022","article-title":"Synthesis, spectroscopic characterization and biological evaluation of unsymmetrical aminosquarylium cyanine dyes","volume":"25","author":"Silva","year":"2017","journal-title":"Bioorg. Med. Chem."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"69","DOI":"10.3322\/caac.20107","article-title":"Global cancer statistics","volume":"61","author":"Jemal","year":"2011","journal-title":"CA Cancer J. Clin."},{"key":"ref_27","first-page":"1","article-title":"Environmental factors inducing human cancers","volume":"41","author":"Parsa","year":"2012","journal-title":"Iran. J. Public Health"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"2543","DOI":"10.1089\/ars.2011.3965","article-title":"Chemotherapy-Induced Weakness and Fatigue in Skeletal Muscle: The Role of Oxidative Stress","volume":"15","author":"Gilliam","year":"2011","journal-title":"Antioxid. Redox Signaling"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Severino, P., De Hollanda, L.M., Santini, A., Reis, L.V., Souto, S.B., Souto, E.B., and Silva, A.M. (2016). Advances in nanobiomaterials for oncology nanomedicine. Nanobiomaterials in Cancer Therapy, Elsevier.","DOI":"10.1016\/B978-0-323-42863-7.00004-9"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"250","DOI":"10.3322\/caac.20114","article-title":"Photodynamic therapy of cancer: An update","volume":"61","author":"Agostinis","year":"2011","journal-title":"CA Cancer J. Clin."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"86","DOI":"10.1016\/j.bbcan.2007.07.001","article-title":"Molecular effectors of multiple cell death pathways initiated by photodynamic therapy","volume":"1776","author":"Buytaert","year":"2007","journal-title":"Biochim. Biophys. Acta (BBA) Rev. Cancer"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1186\/s40824-018-0140-z","article-title":"Clinical development of photodynamic agents and therapeutic applications","volume":"22","author":"Baskaran","year":"2018","journal-title":"Biomater. Res."},{"key":"ref_33","first-page":"1","article-title":"Photodynamic therapy in cancer treatment\u2014An update review","volume":"5","author":"Terra","year":"2019","journal-title":"JCMT"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"732","DOI":"10.1080\/09546634.2019.1569752","article-title":"An update on topical photodynamic therapy for clinical dermatologists","volume":"30","author":"Nguyen","year":"2019","journal-title":"J. Dermatol. Treat."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Blasi, M.A., Pagliara, M.M., Lanza, A., Sammarco, M.G., Caputo, C.G., Grimaldi, G., and Scupola, A. (2018). Photodynamic Therapy in Ocular Oncology. Biomedicines, 6.","DOI":"10.3390\/biomedicines6010017"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"202","DOI":"10.3109\/09546634.2014.927816","article-title":"Photodynamic therapy for psoriasis","volume":"26","author":"Choi","year":"2015","journal-title":"J. Dermatol. Treat."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Silva, A.M., Siopa, J.R., Martins-Gomes, C., Teixeira, M.C., Santos, D.J., Dos Anjos Pires, M., and Andreani, T. (2018). New strategies for the treatment of autoimmune diseases using nanotechnologies. Emerging Nanotechnologies in Immunology, Elsevier.","DOI":"10.1016\/B978-0-323-40016-9.00006-3"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"66","DOI":"10.1159\/000367603","article-title":"Ranibizumab plus Verteporfin Photodynamic Therapy in Neovascular Age-Related Macular Degeneration: 12 Months of Retreatment and Vision Outcomes from a Randomized Study","volume":"233","author":"Hatz","year":"2014","journal-title":"Ophthalmologica"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"340","DOI":"10.1039\/B915149B","article-title":"The role of porphyrin chemistry in tumor imaging and photodynamic therapy","volume":"40","author":"Ethirajan","year":"2011","journal-title":"Chem. Soc. Rev."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"806","DOI":"10.1016\/j.dyepig.2018.09.009","article-title":"Design and synthesis of symmetrical pentamethine cyanine dyes as NIR photosensitizers for PDT","volume":"160","author":"Ciubini","year":"2019","journal-title":"Dyes Pigment."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"5246","DOI":"10.3748\/wjg.v24.i46.5246","article-title":"Effect of photodynamic therapy with (17R,18R)-2-(1-hexyloxyethyl)-2-devinyl chlorine E6 trisodium salt on pancreatic cancer cells In Vitro and In Vivo","volume":"24","author":"Shen","year":"2018","journal-title":"WJG"},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Mehraban, N., Musich, P., and Freeman, H. (2019). Synthesis and Encapsulation of a New Zinc Phthalocyanine Photosensitizer into Polymeric Nanoparticles to Enhance Cell Uptake and Phototoxicity. Appl. Sci., 9.","DOI":"10.3390\/app9030401"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"137","DOI":"10.1016\/j.apsb.2017.09.003","article-title":"An updated overview on the development of new photosensitizers for anticancer photodynamic therapy","volume":"8","author":"Zhang","year":"2018","journal-title":"Acta Pharm. Sin. B"},{"key":"ref_44","unstructured":"Amarego, W.L.F., and Perrin, D.D. (1996). Purification of Laboratory Chemicals, Butterworth-Heinemann. [4th ed.]."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"320","DOI":"10.3390\/70300320","article-title":"Synthesis and Spectroscopic Characterisation of N-Alkyl Quaternary Ammonium Salts Typical Precursors of Cyanines","volume":"7","author":"Pardal","year":"2002","journal-title":"Molecules"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"125","DOI":"10.1016\/j.dyepig.2004.05.003","article-title":"Synthesis of novel squaraine dyes and their intermediates","volume":"64","author":"Tatarets","year":"2005","journal-title":"Dyes Pigment."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"13486","DOI":"10.1021\/la101257b","article-title":"Molecular Design of Near-IR Harvesting Unsymmetrical Squaraine Dyes","volume":"26","author":"Kim","year":"2010","journal-title":"Langmuir"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"3645","DOI":"10.1055\/s-0030-1258258","article-title":"Limitations of the \u2018Two-Phase\u2019 Doebner-Miller Reaction for the Synthesis of Quinolines","volume":"2010","author":"Reynolds","year":"2010","journal-title":"Synthesis"},{"key":"ref_49","unstructured":"Pacheco, M.L.F.M., Fri\u00e3es, S.F.P., Boto, R.E., Almeida, P., Silva, A.M., and Reis, L.V. (2017). Synthesis of a Squarylium Cyanine Dye as Potential Photosensitizer for Photodynamic Therapy (PDT). Comprehensive Organic Chemistry Experiments for the Laboratory Classroom, The Royal Society of Chemistry."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"160","DOI":"10.1016\/j.carbpol.2016.05.060","article-title":"Porphyrin dye into biopolymeric chitosan films for localized photodynamic therapy of cancer","volume":"151","author":"Ferreira","year":"2016","journal-title":"Carbohydr. Polym."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"916","DOI":"10.1016\/j.colsurfb.2014.10.047","article-title":"Surface engineering of silica nanoparticles for oral insulin delivery: Characterization and cell toxicity studies","volume":"123","author":"Andreani","year":"2014","journal-title":"Colloids Surf. B Biointerfaces"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"28","DOI":"10.1016\/j.ejmech.2014.04.084","article-title":"Solid lipid nanoparticles for hydrophilic biotech drugs: Optimization and cell viability studies (Caco-2 & HEPG-2 cell lines)","volume":"81","author":"Severino","year":"2014","journal-title":"Eur. J. Med. Chem."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"267","DOI":"10.1016\/j.jphotochem.2003.12.007","article-title":"Efficiency of singlet oxygen generation of aminosquarylium cyanines","volume":"163","author":"Santos","year":"2004","journal-title":"J. Photochem. Photobiol. A Chem."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"187","DOI":"10.1016\/j.ejmech.2016.02.035","article-title":"Squaraines bearing halogenated moieties as anticancer photosensitizers: Synthesis, characterization and biological evaluation","volume":"113","author":"Serpe","year":"2016","journal-title":"Eur. J. Med. Chem."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"1948","DOI":"10.1039\/c3pp50132a","article-title":"Photochemical properties of squarylium cyanine dyes","volume":"12","author":"Ferreira","year":"2013","journal-title":"Photochem. Photobiol. Sci."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"4467","DOI":"10.1016\/j.bmcl.2017.08.004","article-title":"Aminosquaraines as potential photodynamic agents: Synthesis and evaluation of In Vitro cytotoxicity","volume":"27","author":"Calhelha","year":"2017","journal-title":"Bioorg. Med. Chem. Lett."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"2188","DOI":"10.1021\/jm901727j","article-title":"Photooxidation and Phototoxicity of \u03c0-Extended Squaraines","volume":"53","author":"Rapozzi","year":"2010","journal-title":"J. Med. Chem."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"159","DOI":"10.1016\/S1010-6030(03)00203-X","article-title":"Singlet oxygen generation ability of squarylium cyanine dyes","volume":"160","author":"Santos","year":"2003","journal-title":"J. Photochem. Photobiol. A Chem."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"911","DOI":"10.1021\/jo00425a036","article-title":"An improvement in the Doebner-Miller synthesis of quinaldines","volume":"42","author":"Leir","year":"1977","journal-title":"J. Org. Chem."},{"key":"ref_60","doi-asserted-by":"crossref","unstructured":"Lima, E., Ferreira, O., Silva, J.F., Santos, A.O., Boto, R.E., Fernandes, J.R., Almeida, P., Silvestre, S.M., and Reis, L.V. (2019). Photodynamic activity of indolenine-based aminosquaraine cyanine dyes: Synthesis and In Vitro photobiological evaluation. Dyes Pigment., 108024.","DOI":"10.1016\/j.dyepig.2019.108024"},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"1053","DOI":"10.1111\/j.1751-1097.2009.00585.x","article-title":"Porphyrin and Nonporphyrin Photosensitizers in Oncology: Preclinical and Clinical Advances in Photodynamic Therapy","volume":"85","author":"Gallagher","year":"2009","journal-title":"Photochem. Photobiol."},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"1706320","DOI":"10.1002\/adma.201706320","article-title":"Near-Infrared-Light-Activatable Nanomaterial-Mediated Phototheranostic Nanomedicines: An Emerging Paradigm for Cancer Treatment","volume":"30","author":"Vankayala","year":"2018","journal-title":"Adv. Mater."},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"1765","DOI":"10.1039\/c5pp00132c","article-title":"Photodynamic therapy (PDT) of cancer: From local to systemic treatment","volume":"14","author":"Arnaut","year":"2015","journal-title":"Photochem. Photobiol. Sci."},{"key":"ref_64","doi-asserted-by":"crossref","unstructured":"van Straten, D., Mashayekhi, V., de Bruijn, H., Oliveira, S., and Robinson, D. (2017). Oncologic Photodynamic Therapy: Basic Principles, Current Clinical Status and Future Directions. Cancers, 9.","DOI":"10.3390\/cancers9020019"},{"key":"ref_65","doi-asserted-by":"crossref","first-page":"14","DOI":"10.1016\/j.pdpdt.2010.12.001","article-title":"Nanodrug applications in photodynamic therapy","volume":"8","author":"Paszko","year":"2011","journal-title":"Photodiagn. Photodyn. Ther."},{"key":"ref_66","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1016\/0968-0004(77)90253-5","article-title":"Singlet oxygen in biological systems","volume":"2","author":"Krinsky","year":"1977","journal-title":"Trends Biochem. Sci."},{"key":"ref_67","doi-asserted-by":"crossref","first-page":"912","DOI":"10.1111\/php.12716","article-title":"Type I and Type II Photosensitized Oxidation Reactions: Guidelines and Mechanistic Pathways","volume":"93","author":"Baptista","year":"2017","journal-title":"Photochem. Photobiol."},{"key":"ref_68","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1016\/0304-3835(86)90100-X","article-title":"Effect of bleaching of porphyrin sensitizers during photodynamic therapy","volume":"33","author":"Moan","year":"1986","journal-title":"Cancer Lett."},{"key":"ref_69","doi-asserted-by":"crossref","first-page":"12162","DOI":"10.1021\/ja0528533","article-title":"Highly Efficient and Photostable Photosensitizer Based on BODIPY Chromophore","volume":"127","author":"Yogo","year":"2005","journal-title":"J. Am. Chem. Soc."},{"key":"ref_70","doi-asserted-by":"crossref","first-page":"1932","DOI":"10.1134\/S1054660X09170071","article-title":"Can efficiency of the photosensitizer be predicted by its photostability in solution?","volume":"19","author":"Ferreira","year":"2009","journal-title":"Laser Phys."},{"key":"ref_71","doi-asserted-by":"crossref","first-page":"153","DOI":"10.1007\/BF00862734","article-title":"An investigation of squaraines as a new class of fluorophores with long-wavelength excitation and emission","volume":"3","author":"Terpetschnig","year":"1993","journal-title":"J. Fluoresc."},{"key":"ref_72","doi-asserted-by":"crossref","first-page":"77","DOI":"10.1007\/978-1-4939-2074-7_5","article-title":"Culture and Functional Characterization of Human Hepatoma HepG2 Cells","volume":"Volume 1250","author":"Vinken","year":"2015","journal-title":"Protocols in In Vitro Hepatocyte Research"},{"key":"ref_73","doi-asserted-by":"crossref","first-page":"4667","DOI":"10.18203\/2320-6012.ijrms20174914","article-title":"Colorectal cancer: A review","volume":"5","year":"2017","journal-title":"Int. J. Res. Med. Sci."},{"key":"ref_74","first-page":"1936","article-title":"Epithelial polarity, villin expression, and enterocytic differentiation of cultured human colon carcinoma cells: A survey of twenty cell lines","volume":"48","author":"Chantret","year":"1988","journal-title":"Cancer Res."},{"key":"ref_75","doi-asserted-by":"crossref","first-page":"703","DOI":"10.1016\/j.tiv.2004.03.012","article-title":"Comparison of alamar blue and MTT assays for high through-put screening","volume":"18","author":"Hamid","year":"2004","journal-title":"Toxicol. In Vitro"},{"key":"ref_76","unstructured":"International Standard (ISO) (2009). Biological Evaluation of Medical Devices. Part 5: Tests for In Vitro Cytotoxicity, International Standard (ISO). [3rd ed.]. ISO-10993-5."},{"key":"ref_77","doi-asserted-by":"crossref","unstructured":"\u00c7elik, T.A. (2018). Role of Cytotoxicity Experiments in Pharmaceutical Development. Cytotoxicity, InTech.","DOI":"10.5772\/intechopen.69919"},{"key":"ref_78","doi-asserted-by":"crossref","first-page":"328","DOI":"10.1038\/nature12624","article-title":"Tumour heterogeneity and cancer cell plasticity","volume":"501","author":"Meacham","year":"2013","journal-title":"Nature"},{"key":"ref_79","doi-asserted-by":"crossref","first-page":"1135","DOI":"10.1002\/hlca.200590084","article-title":"Synthesis and Photochemical Evaluation of Iodinated Squarylium Cyanine Dyes","volume":"88","author":"Santos","year":"2005","journal-title":"HCA"}],"container-title":["Applied Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-3417\/9\/24\/5414\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T13:41:18Z","timestamp":1760190078000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-3417\/9\/24\/5414"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,12,11]]},"references-count":79,"journal-issue":{"issue":"24","published-online":{"date-parts":[[2019,12]]}},"alternative-id":["app9245414"],"URL":"https:\/\/doi.org\/10.3390\/app9245414","relation":{},"ISSN":["2076-3417"],"issn-type":[{"value":"2076-3417","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,12,11]]}}}