Pub Date : 2026-05-01Epub Date: 2025-12-16DOI: 10.1016/j.dyepig.2025.113507
Maciej Spiegel
A computational methodology is presented for the rational design of anthraquinone-based, heavy-atom–free photosensitisers optimised for two-photon photodynamic therapy in hypoxic tumours within the NIR region. Twelve derivatives were evaluated for two-photon absorption, excited states dynamics, redox reactivity, and ADME properties. Four lead compounds—Oxz, Tdz, Prd, and Pmd—exhibited Herzberg–Teller-enabled intersystem crossing and sufficient triplet-state lifetimes to permit diffusion-limited interactions. The Redox Activity and Chemical Trends Map, validated against Marcus theory, distinguished distinct mechanistic profiles amongst the derivatives, with lead candidates exhibiting selective biomolecular oxidation (Type III). Notably, Pmd retained a reasonable phosphorescence rate despite concurrent processes, indicating likelihood of the sustained Type II reactivity under quenching. SwissADME analysis confirmed favourable permeability and synthetic accessibility. This integrative computational framework—though developed for anthraquinones—is generalisable to diverse scaffolds, facilitating early-stage prioritisation of oxygen-independent, multimodal two–photon PDT candidates for hypoxic cancer treatment.
提出了一种计算方法，用于合理设计基于蒽醌的无重原子光敏剂，该光敏剂优化用于近红外区域内缺氧肿瘤的双光子光动力治疗。对12种衍生物的双光子吸收、激发态动力学、氧化还原反应性和ADME性能进行了评价。四种先导化合物oxz， Tdz， Prd和pmd表现出赫茨伯格-泰勒系统间交叉和足够的三重态寿命，以允许扩散限制相互作用。氧化还原活性和化学趋势图（Redox Activity and Chemical Trends Map）根据Marcus理论进行了验证，在衍生物中区分出不同的机制特征，主要候选衍生物表现出选择性生物分子氧化（III型）。值得注意的是，Pmd保持了合理的磷光率，尽管有并发的过程，这表明在淬火下可能持续II型反应性。SwissADME分析证实了良好的渗透率和合成可达性。这种综合计算框架虽然是为蒽醌类开发的，但可推广到不同的支架，促进缺氧癌症治疗中不依赖氧的多模态双光子PDT候选物的早期优先排序。
{"title":"In silico design of anthraquinone-based two-photon photosensitisers for NIR-activated photodynamic therapy in hypoxic tumors","authors":"Maciej Spiegel","doi":"10.1016/j.dyepig.2025.113507","DOIUrl":"10.1016/j.dyepig.2025.113507","url":null,"abstract":"<div><div>A computational methodology is presented for the rational design of anthraquinone-based, heavy-atom–free photosensitisers optimised for two-photon photodynamic therapy in hypoxic tumours within the NIR region. Twelve derivatives were evaluated for two-photon absorption, excited states dynamics, redox reactivity, and ADME properties. Four lead compounds—<strong>Oxz</strong>, <strong>Tdz</strong>, <strong>Prd</strong>, and <strong>Pmd</strong>—exhibited Herzberg–Teller-enabled intersystem crossing and sufficient triplet-state lifetimes to permit diffusion-limited interactions. The Redox Activity and Chemical Trends Map, validated against Marcus theory, distinguished distinct mechanistic profiles amongst the derivatives, with lead candidates exhibiting selective biomolecular oxidation (Type III). Notably, <strong>Pmd</strong> retained a reasonable phosphorescence rate despite concurrent processes, indicating likelihood of the sustained Type II reactivity under quenching. SwissADME analysis confirmed favourable permeability and synthetic accessibility. This integrative computational framework—though developed for anthraquinones—is generalisable to diverse scaffolds, facilitating early-stage prioritisation of oxygen-independent, multimodal two–photon PDT candidates for hypoxic cancer treatment.</div></div>","PeriodicalId":302,"journal":{"name":"Dyes and Pigments","volume":"248 ","pages":"Article 113507"},"PeriodicalIF":4.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145847711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2025-12-19DOI: 10.1016/j.dyepig.2025.113484
Raul Marques Novais , Pedro I.P. Leite , Sem Bleus , Thanh Chung Pham , Ricardo Vessecchi , Daniel Escudero , Wim Dehaen , Flavio da Silva Emery
A novel class of pyrimido[1,6-b]indazole fluorophores was synthesized via a concise condensation featuring a 6-endo-dig cyclization. The ring system displays large Stokes shifts (99–115 nm) and positive solvatochromism, suggesting an intramolecular charge transfer. Suzuki–Miyaura cross-coupling enables π-extension to derivatives with improved quantum yields and Stokes shifts exceeding 130 nm. TD-DFT calculations corroborate these trends, highlighting their potential for advanced fluorescence-based technologies.
{"title":"A novel pyrimido[1,6-b]indazole heterocycle as a building block for the design of low-molecular-weight fluorescent probes with large Stokes shifts","authors":"Raul Marques Novais , Pedro I.P. Leite , Sem Bleus , Thanh Chung Pham , Ricardo Vessecchi , Daniel Escudero , Wim Dehaen , Flavio da Silva Emery","doi":"10.1016/j.dyepig.2025.113484","DOIUrl":"10.1016/j.dyepig.2025.113484","url":null,"abstract":"<div><div>A novel class of pyrimido[1,6-<em>b</em>]indazole fluorophores was synthesized via a concise condensation featuring a 6<em>-endo-dig</em> cyclization. The ring system displays large Stokes shifts (99–115 nm) and positive solvatochromism, suggesting an intramolecular charge transfer. Suzuki–Miyaura cross-coupling enables π-extension to derivatives with improved quantum yields and Stokes shifts exceeding 130 nm. TD-DFT calculations corroborate these trends, highlighting their potential for advanced fluorescence-based technologies.</div></div>","PeriodicalId":302,"journal":{"name":"Dyes and Pigments","volume":"248 ","pages":"Article 113484"},"PeriodicalIF":4.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145882899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2025-12-26DOI: 10.1016/j.dyepig.2025.113528
Mónica G. Flores-Amaro , Julio E. Castañeda-Delgado , Rosa M. Jiménez-Barrera , Horacio Reyes-Pérez , Emanuel Bojórquez-Quintal , Abner Esperanza-Norzagaray , Tania I. Coral-Martinez , Iván Díaz-Payán , María C. García-López , Rodrigo Chan-Navarro
In this work, we have demonstrated blue and visible LED irradiation promoted synthesis of organoboron esters, achieved in just 30 min with near-quantitative yields. Their X-ray structures demonstrated that the boron atoms adopt a distorted tetrahedral geometry and the aryl substituents from aryl boric acid along the vertical axis gave an asymmetric boron center. The photostability properties were analyzed in solution, revealing that 1 and 2 featured axial-substituted methyl groups on the tetrahedral boron atom and exhibit superior stability compared to their derivatives. Theoretical calculations were performed to gain insight into the structures and the supramolecular associations within crystal structures. Interestingly, the compounds demonstrated good solubility and high biocompatibility, making them promising fluorescent dyes for applications in biological and biomedical sciences. Additionally, compounds 2, 3 and 4 exhibited strong, non-hazardous green fluorescence when tested against the C33A cervical cancer cell line highlighting their potential usage in the study of biological processes.
{"title":"Visible and blue LED irradiation-assisted one-step synthesis of novel organoboron heterocycles as cell imaging agents","authors":"Mónica G. Flores-Amaro , Julio E. Castañeda-Delgado , Rosa M. Jiménez-Barrera , Horacio Reyes-Pérez , Emanuel Bojórquez-Quintal , Abner Esperanza-Norzagaray , Tania I. Coral-Martinez , Iván Díaz-Payán , María C. García-López , Rodrigo Chan-Navarro","doi":"10.1016/j.dyepig.2025.113528","DOIUrl":"10.1016/j.dyepig.2025.113528","url":null,"abstract":"<div><div>In this work, we have demonstrated blue and visible LED irradiation promoted synthesis of organoboron esters, achieved in just 30 min with near-quantitative yields. Their X-ray structures demonstrated that the boron atoms adopt a distorted tetrahedral geometry and the aryl substituents from aryl boric acid along the vertical axis gave an asymmetric boron center. The photostability properties were analyzed in solution, revealing that <strong>1</strong> and <strong>2</strong> featured axial-substituted methyl groups on the tetrahedral boron atom and exhibit superior stability compared to their derivatives. Theoretical calculations were performed to gain insight into the structures and the supramolecular associations within crystal structures. Interestingly, the compounds demonstrated good solubility and high biocompatibility, making them promising fluorescent dyes for applications in biological and biomedical sciences. Additionally, compounds <strong>2</strong>, <strong>3</strong> and <strong>4</strong> exhibited strong, non-hazardous green fluorescence when tested against the C33A cervical cancer cell line highlighting their potential usage in the study of biological processes.</div></div>","PeriodicalId":302,"journal":{"name":"Dyes and Pigments","volume":"248 ","pages":"Article 113528"},"PeriodicalIF":4.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145883003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2026-01-14DOI: 10.1016/j.dyepig.2026.113576
Long Fang , Qixin Zhou , Shujun Wang , Rui Wang , Liang Yin , Yaping Wang , Hanping He
Traditional fluoresceins have been widely employed in chemical and biological analyses owing to their high molar extinction coefficients, excellent fluorescence quantum yields, and low toxicity. However, their practical application in biological imaging is limited by a small Stokes shift, which arises from the symmetry of their molecular structures and results in a low signal-to-noise ratio as well as significant fluorescence self-quenching. In this work, a series of novel asymmetric carboxyl fluorescein derivatives were successfully synthesized by incorporating various thienyl heterocyclic rings in the fluorescein scaffold. Among these derivatives, Fam-T-Ph exhibited a remarkably large Stokes shift of up to 108 nm, along with a red-shifted wavelength (632 nm). Furthermore, immunofluorescence staining experiments confirmed that Fam-T-Ph possesses strong and reliable fluorescence imaging performance. These newly designed derivatives hold potential as fluorescent labeling agents for biological applications.
{"title":"A novel asymmetric fluorescein derivative with larger Stokes shift: design, synthesis and application in immunofluorescence tissue staining","authors":"Long Fang , Qixin Zhou , Shujun Wang , Rui Wang , Liang Yin , Yaping Wang , Hanping He","doi":"10.1016/j.dyepig.2026.113576","DOIUrl":"10.1016/j.dyepig.2026.113576","url":null,"abstract":"<div><div>Traditional fluoresceins have been widely employed in chemical and biological analyses owing to their high molar extinction coefficients, excellent fluorescence quantum yields, and low toxicity. However, their practical application in biological imaging is limited by a small Stokes shift, which arises from the symmetry of their molecular structures and results in a low signal-to-noise ratio as well as significant fluorescence self-quenching. In this work, a series of novel asymmetric carboxyl fluorescein derivatives were successfully synthesized by incorporating various thienyl heterocyclic rings in the fluorescein scaffold. Among these derivatives, <strong>Fam-T-Ph</strong> exhibited a remarkably large Stokes shift of up to 108 nm, along with a red-shifted wavelength (632 nm). Furthermore, immunofluorescence staining experiments confirmed that <strong>Fam-T-Ph</strong> possesses strong and reliable fluorescence imaging performance. These newly designed derivatives hold potential as fluorescent labeling agents for biological applications.</div></div>","PeriodicalId":302,"journal":{"name":"Dyes and Pigments","volume":"248 ","pages":"Article 113576"},"PeriodicalIF":4.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145973451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2026-01-12DOI: 10.1016/j.dyepig.2026.113561
Qing-ya Sun , Jia-xue Huang , Yu-xuan Li , Zheng-guang Sun , Xuan-feng Jiang
Tuning the electronic structure of organic dye photocatalysts is essential for boosting their performance in photocatalytic organic transformations. In this work, we synthesized two pyridine-based organic dye photocatalysts, TPA-by and TPE-by, via Suzuki coupling. Featuring donor–acceptor (D–A) conjugated architectures, these pyridine-containing emissive molecules exhibit strong electronic excitation and favorable redox properties. In acetonitrile, the fluorescence lifetimes of TPA-by and TPE-by were measured as 4.97 ns and 4.26 ns, corresponding to optical band gaps (Eg) of 2.51 eV and 2.73 eV, respectively. The pronounced D-A character significantly enhances their photocatalytic activity. Under mild conditions, TPA-by and TPE-by achieve high efficiencies of 97 % and 95 %, respectively, in the oxidative coupling of benzylamine. Their performance is comparable to that of conventional polymer and metal-complex catalysts, while benefiting from milder reaction conditions and faster kinetics. Moreover, both catalysts retain around 90 % efficiency after multiple reuse cycles. Mechanistic investigations, including quenching experiments and electron paramagnetic resonance (EPR) spectroscopy, indicate that reactive oxygen species (ROS) are generated via an energy transfer (ET) pathway, which subsequently drive the coupling reaction through substrate redox processes. This work establishes a practical design strategy for developing efficient and stable organic photocatalysts, while also providing important mechanistic knowledge that broadens their potential application scope.
{"title":"Chromophore-dependent photocatalytic benzylamine coupling mediated by organic dye molecules","authors":"Qing-ya Sun , Jia-xue Huang , Yu-xuan Li , Zheng-guang Sun , Xuan-feng Jiang","doi":"10.1016/j.dyepig.2026.113561","DOIUrl":"10.1016/j.dyepig.2026.113561","url":null,"abstract":"<div><div>Tuning the electronic structure of organic dye photocatalysts is essential for boosting their performance in photocatalytic organic transformations. In this work, we synthesized two pyridine-based organic dye photocatalysts, <strong>TPA-by</strong> and <strong>TPE-by</strong>, via Suzuki coupling. Featuring donor–acceptor (D–A) conjugated architectures, these pyridine-containing emissive molecules exhibit strong electronic excitation and favorable redox properties. In acetonitrile, the fluorescence lifetimes of <strong>TPA-by</strong> and <strong>TPE-by</strong> were measured as 4.97 ns and 4.26 ns, corresponding to optical band gaps (E<sub>g</sub>) of 2.51 eV and 2.73 eV, respectively. The pronounced D-A character significantly enhances their photocatalytic activity. Under mild conditions, <strong>TPA-by</strong> and <strong>TPE-by</strong> achieve high efficiencies of 97 % and 95 %, respectively, in the oxidative coupling of benzylamine. Their performance is comparable to that of conventional polymer and metal-complex catalysts, while benefiting from milder reaction conditions and faster kinetics. Moreover, both catalysts retain around 90 % efficiency after multiple reuse cycles. Mechanistic investigations, including quenching experiments and electron paramagnetic resonance (EPR) spectroscopy, indicate that reactive oxygen species (ROS) are generated via an energy transfer (ET) pathway, which subsequently drive the coupling reaction through substrate redox processes. This work establishes a practical design strategy for developing efficient and stable organic photocatalysts, while also providing important mechanistic knowledge that broadens their potential application scope.</div></div>","PeriodicalId":302,"journal":{"name":"Dyes and Pigments","volume":"248 ","pages":"Article 113561"},"PeriodicalIF":4.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145973448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nitroxynil (NIT) is a commonly used veterinary medicine to treat fascioliasis in food and milk producing cattle and sheep. The residues from the edible animal food products cause severe health issues in humans. Therefore, it is of significant importance to generate an analytical approach for the detection of NIT in food products. Herein, the tyrosine derived carbon dots (T-CDs) were successfully synthesized by a simple one step hydrothermal method using tyrosine and ethylenediamine. The preparation conditions of T-CDs were optimized and analysed by UV–vis spectroscopy, fluorescence spectroscopy, PXRD, TEM, FT-IR and XPS. T-CDs shows high selectivity, good anti-interference ability (1500–fold), high sensitivity (LOD: 5.2 nM), fast response (5 min) towards the detection of NIT. T-CDs expressed contrast fluorescent confocal images depending on its concentration and NIT concentration. The detection of NIT in food samples such as cow meat, mutton, cow milk and also human urine samples was demonstrated. Good recovery results were achieved and the acquired findings were validated by HPLC detection method. All of the results prove that the present sensing strategy is simple, sensitive, selective towards NIT in food and urine samples, it provides a pathway to create an interesting new fluorescent sensor for the estimation of NIT.
{"title":"Tyrosine-derived carbon dots as a highly sensitive sensor for nitroxynil in food, urine, and live cells","authors":"Hao Tang , Jindong Dai , Jian Shen , Mian Zhang , Xue Xia , Thangamani Kanagaraj , Dongwei Zhu , Kanagaraj Rajalakshmi , Muthusamy Selvaraj , Siyi Wu , Xiaodong Zhou","doi":"10.1016/j.dyepig.2025.113512","DOIUrl":"10.1016/j.dyepig.2025.113512","url":null,"abstract":"<div><div>Nitroxynil (NIT) is a commonly used veterinary medicine to treat fascioliasis in food and milk producing cattle and sheep. The residues from the edible animal food products cause severe health issues in humans. Therefore, it is of significant importance to generate an analytical approach for the detection of NIT in food products. Herein, the tyrosine derived carbon dots (T-CDs) were successfully synthesized by a simple one step hydrothermal method using tyrosine and ethylenediamine. The preparation conditions of T-CDs were optimized and analysed by UV–vis spectroscopy, fluorescence spectroscopy, PXRD, TEM, FT-IR and XPS. T-CDs shows high selectivity, good anti-interference ability (1500–fold), high sensitivity (LOD: 5.2 nM), fast response (5 min) towards the detection of NIT. T-CDs expressed contrast fluorescent confocal images depending on its concentration and NIT concentration. The detection of NIT in food samples such as cow meat, mutton, cow milk and also human urine samples was demonstrated. Good recovery results were achieved and the acquired findings were validated by HPLC detection method. All of the results prove that the present sensing strategy is simple, sensitive, selective towards NIT in food and urine samples, it provides a pathway to create an interesting new fluorescent sensor for the estimation of NIT.</div></div>","PeriodicalId":302,"journal":{"name":"Dyes and Pigments","volume":"248 ","pages":"Article 113512"},"PeriodicalIF":4.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145939845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2026-01-07DOI: 10.1016/j.dyepig.2026.113557
Yongfei Huang, Zifan Gao, Zhefeng Fan
In eukaryotic cells, the dynamic interplay between lipid droplets (LDs) and lysosomes is crucial for cellular processes like autophagy and apoptosis. However, conventional approaches, such as multi-probe kits or non-discriminative single probes, often suffer from spectral crosstalk and erroneous localization, complicating the simultaneous and precise tracking of these two organelles. A key challenge in visualizing their interaction is the lack of a single probe capable of independently targeting and distinguishing both organelles based on their unique physicochemical properties. Herein, we present LDs-Lyso-pH, a novel dual-responsive fluorescent probe based on a coumarin-benzoindole scaffold, which enables simultaneous and distinct visualization of LDs and lysosomes by sensing polarity and pH. In lysosomes, the probe exists in an open-ring form, emitting red fluorescence in the acidic environment, while in the neutral lipid environment of LDs, it switches to a closed-ring form, yielding blue fluorescence. We successfully demonstrated the probe's capability to visually monitor organelle dynamics: upon drug-induced perturbations, an increase in lysosomal pH led to a quenching of red emission, whereas LDs damage resulted in a loss of blue fluorescence. Furthermore, leveraging this pH-dependent fluorescence, we developed a portable detection tool using a mobile RGB color recognition application to estimate the pH of actual sample. This work provides a powerful molecular tool for deciphering LDs-lysosomes interactions in cell fate decisions and showcases a potential point-of-care sensing strategy.
{"title":"Unraveling the dynamic interplay between lipid droplets and lysosomes during autophagy and apoptosis with a dual-responsive single fluorescent probe","authors":"Yongfei Huang, Zifan Gao, Zhefeng Fan","doi":"10.1016/j.dyepig.2026.113557","DOIUrl":"10.1016/j.dyepig.2026.113557","url":null,"abstract":"<div><div>In eukaryotic cells, the dynamic interplay between lipid droplets (LDs) and lysosomes is crucial for cellular processes like autophagy and apoptosis. However, conventional approaches, such as multi-probe kits or non-discriminative single probes, often suffer from spectral crosstalk and erroneous localization, complicating the simultaneous and precise tracking of these two organelles. A key challenge in visualizing their interaction is the lack of a single probe capable of independently targeting and distinguishing both organelles based on their unique physicochemical properties. Herein, we present <strong>LDs-Lyso-pH</strong>, a novel dual-responsive fluorescent probe based on a coumarin-benzoindole scaffold, which enables simultaneous and distinct visualization of LDs and lysosomes by sensing polarity and pH. In lysosomes, the probe exists in an open-ring form, emitting red fluorescence in the acidic environment, while in the neutral lipid environment of LDs, it switches to a closed-ring form, yielding blue fluorescence. We successfully demonstrated the probe's capability to visually monitor organelle dynamics: upon drug-induced perturbations, an increase in lysosomal pH led to a quenching of red emission, whereas LDs damage resulted in a loss of blue fluorescence. Furthermore, leveraging this pH-dependent fluorescence, we developed a portable detection tool using a mobile RGB color recognition application to estimate the pH of actual sample. This work provides a powerful molecular tool for deciphering LDs-lysosomes interactions in cell fate decisions and showcases a potential point-of-care sensing strategy.</div></div>","PeriodicalId":302,"journal":{"name":"Dyes and Pigments","volume":"248 ","pages":"Article 113557"},"PeriodicalIF":4.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145939791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2026-01-03DOI: 10.1016/j.dyepig.2026.113550
Erivaldo P. da Costa , André H. de Oliveira , José V.S. Medeiros , Thiago I.S. Santos , Gustavo S. dos Santos , Ioris R.C. Eeckhout , Jannyely M. Neri , Eduard Westphal , Renata M. Araújo , Rodrigo Cristiano , Miguel A.F. de Souza , Fabrício G. Menezes
Liquid crystals (LCs) are still of great scientific and technological interest, with many possibilities of application still on the horizon. Many of the mesogenic structures present heterocycles as a source of structural modifications and even of differentiated properties. Quinoxalines are among the commonly used heterocycles. However, its use is almost restricted to discotic LCs, being practically neglected in calamitic and bent structures. In this study, we report the synthesis, liquid crystalline behavior, and optical properties of four 4-(quinoxalin-2-yl)phenyl 4-alkoxylbenzoates-based hockey-stick like mesogens, a yet unexplored scaffold with molecular anisotropy. All target-compounds were characterized as enantiotropic liquid crystals, with interesting mesophase ranges (up to 111 °C), which were identified as both nematic and smectic. Their mesophases were characterized by polarized optical microscopy (POM) and differential scanning calorimetry (DSC). We found that small structural differences in the compounds can lead to distinct phase transition patterns. The photophysical data obtained in different solvents revealed that the presence of two ortho-methyl substituents on the quinoxaline ring significantly enhances the fluorescence of the mesogenic compounds compared with the unsubstituted analog, leading to higher emissions, particularly in methanol solution (ϕPL = 15 %). In addition, a relevant aggregation-induced emission enhancement (AIEE) was verified in aqueous acetonitrile (ϕPL = 29 %) and notably in methanol (ϕPL = 61 %). Furthermore, whereas protonation of quinoxaline does not lead to fluorescence improvement in polar solvents, a prominent emission increase is observed in dichloromethane. The acidochromic response of methyl-substituted compound enables acid sensing in biphasic system as well as sequential gaseous acid/base detection using a paper-based disposable sensor. Computational studies support experimental findings on distinct photophysical behavior of unsubstituted and ortho-dimethyl-substituted quinoxaline mesogens, in which emission observed in the later mesogen is strongly modulated by structural relaxation and oscillator strengths. The results herein reported are relevant to the development of fluorescent calamitic quinoxaline-based liquid crystals, still marginally reported.
{"title":"Thermal, mesomorphic and photophysical properties of hockey stick-like quinoxaline-based liquid crystals","authors":"Erivaldo P. da Costa , André H. de Oliveira , José V.S. Medeiros , Thiago I.S. Santos , Gustavo S. dos Santos , Ioris R.C. Eeckhout , Jannyely M. Neri , Eduard Westphal , Renata M. Araújo , Rodrigo Cristiano , Miguel A.F. de Souza , Fabrício G. Menezes","doi":"10.1016/j.dyepig.2026.113550","DOIUrl":"10.1016/j.dyepig.2026.113550","url":null,"abstract":"<div><div>Liquid crystals (LCs) are still of great scientific and technological interest, with many possibilities of application still on the horizon. Many of the mesogenic structures present heterocycles as a source of structural modifications and even of differentiated properties. Quinoxalines are among the commonly used heterocycles. However, its use is almost restricted to discotic LCs, being practically neglected in calamitic and bent structures. In this study, we report the synthesis, liquid crystalline behavior, and optical properties of four 4-(quinoxalin-2-yl)phenyl 4-alkoxylbenzoates-based hockey-stick like mesogens, a yet unexplored scaffold with molecular anisotropy. All target-compounds were characterized as enantiotropic liquid crystals, with interesting mesophase ranges (up to 111 °C), which were identified as both nematic and smectic. Their mesophases were characterized by polarized optical microscopy (POM) and differential scanning calorimetry (DSC). We found that small structural differences in the compounds can lead to distinct phase transition patterns. The photophysical data obtained in different solvents revealed that the presence of two <em>ortho</em>-methyl substituents on the quinoxaline ring significantly enhances the fluorescence of the mesogenic compounds compared with the unsubstituted analog, leading to higher emissions, particularly in methanol solution (ϕ<sub>PL</sub> = 15 %). In addition, a relevant aggregation-induced emission enhancement (AIEE) was verified in aqueous acetonitrile (ϕ<sub>PL</sub> = 29 %) and notably in methanol (ϕ<sub>PL</sub> = 61 %). Furthermore, whereas protonation of quinoxaline does not lead to fluorescence improvement in polar solvents, a prominent emission increase is observed in dichloromethane. The acidochromic response of methyl-substituted compound enables acid sensing in biphasic system as well as sequential gaseous acid/base detection using a paper-based disposable sensor. Computational studies support experimental findings on distinct photophysical behavior of unsubstituted and ortho-dimethyl-substituted quinoxaline mesogens, in which emission observed in the later mesogen is strongly modulated by structural relaxation and oscillator strengths. The results herein reported are relevant to the development of fluorescent calamitic quinoxaline-based liquid crystals, still marginally reported.</div></div>","PeriodicalId":302,"journal":{"name":"Dyes and Pigments","volume":"248 ","pages":"Article 113550"},"PeriodicalIF":4.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145939792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2026-01-07DOI: 10.1016/j.dyepig.2026.113558
You-Ping Ma , Shuangchen Li , Min Zhao , Liwei Yao , Xiao-Ping Cao , Zi-Fa Shi , Yanqin Miao
Organic light-emitting diodes (OLEDs) have attracted tremendous research interest over the past few decades, attributed to the portability and low power consumption. Various organic molecules with thermally activated delayed fluorescence (TADF) properties have been developed and have achieved satisfactory efficiencies when employed in the light-emitting layer. Herein, we synthesized BTD-PXZ-F and BTD-PXZ-Cz by employing a strategy that adjusts the substituents on the BTD-PXZ to optimize molecular properties and packing behavior, maintaining its TADF properties while significantly improving the thermal stability and luminescence efficiency. The results show that the thermal stability of BTD-PXZ-F did not change significantly compared to BTD-PXZ, but its luminescence efficiency increased from 11.4 % to 29.9 %. In contrast, the decomposition temperature and glass transition temperature of BTD-PXZ-Cz increased by 55 °C and 108 °C, respectively, and the luminescence efficiency increased from 11.4 % to 27 % due to the introduction of carbazole groups. Furthermore, OLED devices employ the modified molecules as the light-emitting layer have also been fabricated, achieving luminous efficiencies of up to 2.3 % and 2.4 %, respectively.
{"title":"Substituent effects on thermally activated delayed fluorescence emitter based on benzo[c][1,2,5]thiadiazole","authors":"You-Ping Ma , Shuangchen Li , Min Zhao , Liwei Yao , Xiao-Ping Cao , Zi-Fa Shi , Yanqin Miao","doi":"10.1016/j.dyepig.2026.113558","DOIUrl":"10.1016/j.dyepig.2026.113558","url":null,"abstract":"<div><div>Organic light-emitting diodes (OLEDs) have attracted tremendous research interest over the past few decades, attributed to the portability and low power consumption. Various organic molecules with thermally activated delayed fluorescence (TADF) properties have been developed and have achieved satisfactory efficiencies when employed in the light-emitting layer. Herein, we synthesized <strong>BTD-PXZ-F</strong> and <strong>BTD-PXZ-Cz</strong> by employing a strategy that adjusts the substituents on the <strong>BTD-PXZ</strong> to optimize molecular properties and packing behavior, maintaining its TADF properties while significantly improving the thermal stability and luminescence efficiency. The results show that the thermal stability of <strong>BTD-PXZ-F</strong> did not change significantly compared to <strong>BTD-PXZ</strong>, but its luminescence efficiency increased from 11.4 % to 29.9 %. In contrast, the decomposition temperature and glass transition temperature of <strong>BTD-PXZ-Cz</strong> increased by 55 °C and 108 °C, respectively, and the luminescence efficiency increased from 11.4 % to 27 % due to the introduction of carbazole groups. Furthermore, OLED devices employ the modified molecules as the light-emitting layer have also been fabricated, achieving luminous efficiencies of up to 2.3 % and 2.4 %, respectively.</div></div>","PeriodicalId":302,"journal":{"name":"Dyes and Pigments","volume":"248 ","pages":"Article 113558"},"PeriodicalIF":4.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145939793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2026-01-16DOI: 10.1016/j.dyepig.2026.113575
Peirong Zhou , Shuai Zhang , Yingying Meng , Kaizheng Liu , Xiaoran Huang , Jiaming Mao , Xianan Gao , Tongying Liang , Liang Yao , Hongwei Song , Congcong Cao , Cheng Zhou
Accurate and multiplexed biomarker detection requires probes that combine high brightness, spectral programmability, and biocompatibility. This work reports a fluorescence-encoding liposome platform based on membrane-intercalating conjugated oligoelectrolytes (MICOEs). Two water-soluble MICOE dyes, red-emissive ZBT and green-emissive ZBen, were designed to mimic phospholipids, enabling spontaneous insertion of their π-conjugated cores into lipid bilayers while exposing ionic end groups to water. Membrane intercalation confines and shields the chromophores, affording up to ∼540-fold fluorescence enhancement and excellent photostability without perturbing vesicle size or permeability, as verified by dynamic light scattering and calcein leakage assays. Curvature-controlled studies reveal that smaller, highly curved liposomes incorporate more dye and display higher brightness, identifying nanoscale curvature as a handle to tune signal output. A pre-addition loading strategy, in which MICOEs co-assemble with lipids, yields nearly quantitative labeling and approximately threefold higher emission than post-addition. The resulting MICOE–liposomes exhibit low cytotoxicity, efficiently stain extracellular vesicles, and, after carcinoembryonic antigen (CEA) antibody conjugation, selectively label A549 cancer cells in confocal and flow cytometry experiments. By varying the ZBT:ZBen ratio, robust and reproducible ratiometric red/green signatures are generated at the single-vesicle level, establishing a versatile, biocompatible encoding platform for high-throughput multiplexed biosensing and diagnostic applications.
{"title":"Fluorescent liposomes based on membrane-intercalating conjugated oligoelectrolytes for fluorescence encoding detection","authors":"Peirong Zhou , Shuai Zhang , Yingying Meng , Kaizheng Liu , Xiaoran Huang , Jiaming Mao , Xianan Gao , Tongying Liang , Liang Yao , Hongwei Song , Congcong Cao , Cheng Zhou","doi":"10.1016/j.dyepig.2026.113575","DOIUrl":"10.1016/j.dyepig.2026.113575","url":null,"abstract":"<div><div>Accurate and multiplexed biomarker detection requires probes that combine high brightness, spectral programmability, and biocompatibility. This work reports a fluorescence-encoding liposome platform based on membrane-intercalating conjugated oligoelectrolytes (MICOEs). Two water-soluble MICOE dyes, red-emissive <strong>ZBT</strong> and green-emissive <strong>ZBen</strong>, were designed to mimic phospholipids, enabling spontaneous insertion of their π-conjugated cores into lipid bilayers while exposing ionic end groups to water. Membrane intercalation confines and shields the chromophores, affording up to ∼540-fold fluorescence enhancement and excellent photostability without perturbing vesicle size or permeability, as verified by dynamic light scattering and calcein leakage assays. Curvature-controlled studies reveal that smaller, highly curved liposomes incorporate more dye and display higher brightness, identifying nanoscale curvature as a handle to tune signal output. A pre-addition loading strategy, in which MICOEs co-assemble with lipids, yields nearly quantitative labeling and approximately threefold higher emission than post-addition. The resulting MICOE–liposomes exhibit low cytotoxicity, efficiently stain extracellular vesicles, and, after carcinoembryonic antigen (CEA) antibody conjugation, selectively label A549 cancer cells in confocal and flow cytometry experiments. By varying the <strong>ZBT</strong>:<strong>ZBen</strong> ratio, robust and reproducible ratiometric red/green signatures are generated at the single-vesicle level, establishing a versatile, biocompatible encoding platform for high-throughput multiplexed biosensing and diagnostic applications.</div></div>","PeriodicalId":302,"journal":{"name":"Dyes and Pigments","volume":"248 ","pages":"Article 113575"},"PeriodicalIF":4.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146034373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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