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Design and Preparation of Organic Fluorescent Materials for Detection and Bio-Imaging

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Materials Chemistry".

Deadline for manuscript submissions: 31 May 2024 | Viewed by 16001

Special Issue Editors

Department of Chemistry, Duke University, Durham, NC 27708, USA
Interests: fluorescence chemistry; supramolecular chemistry; polymer chemistry
Institute of Biochemistry and Cell Biology, Shanghai Institute for Biological Sciences Chinese Academy of Sciences, Shanghai, China
Interests: fluorescent probes; magnetic resonance imaging (MRI); nanomaterials; siRNA delivery; bio-imaging

Special Issue Information

Dear Colleagues,

Owing to high selectivity, good sensitivity, and rapid response, organic fluorescent materials (OFMs) have emerged as a powerful tool for detecting different analytes from radicals, cations/anions to molecules, as well as imaging from subcellular structures and cells to entire multicellular organisms, tissues, and organs. Correspondingly, as the development of OFMs together with the detection or imaging technologies, remarkable progresses have been made in the design, synthesis, mechanistic studies, and biological application of various fluorescent probes over the past decades. By involving OFMs, scientists can not only realize the detection of chem/bio-active species both in environment and biological system then study their related bio-functions, but also investigate the specific organelle and their dynamics and interactions, or use directly for detecting, diagnosing, and characterizing diseases in clinical medicine to facilitate disease treatment. All these, on one hand, can be used to create images of the whole body, anatomical areas, organs, tissues, and biological markers down to the molecular level; on the other hand, must be meaningful on in vivo chemical biology research, clinical diagnostics, as well as screening and discovery of new drugs.

In this Special Issue, we will publish a collection of manuscripts that describe the latest advances on organic fluorescent materials for detection and bio-imaging, such as new organic fluorophores, new sensing strategies toward environmental analytes or biological species, bio-imaging, and new applications. Topics of interest include, but are not limited to:

  • Fluorescent Chemistry;
  • Analytical Chemistry;
  • Chemosensor;
  • Bio-imaging.

Dr. Xujun Zheng
Dr. Wencheng Zhu
Guest Editors

Manuscript Submission Information

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • fluorescent probes
  • bio-imaging
  • organic fluorophores

Published Papers (10 papers)

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Research

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12 pages, 6913 KiB  
Article
A “Pincer” Type of Acridine–Triazole Fluorescent Dye for Iodine Detection by Both ‘Naked-Eye’ Colorimetric and Fluorometric Modes
by Mei Yu, Lu Jiang, Lan Mou, Xi Zeng, Ruixiao Wang, Tao Peng, Fuyong Wu and Tianzhu Shi
Molecules 2024, 29(6), 1355; https://doi.org/10.3390/molecules29061355 - 19 Mar 2024
Viewed by 328
Abstract
Iodine, primarily in the form of iodide (I), is the bioavailable form for the thyroid in the human body. Both deficiency and excess intake of iodide can lead to serious health issues, such as thyroid disease. Selecting iodide ions among anions [...] Read more.
Iodine, primarily in the form of iodide (I), is the bioavailable form for the thyroid in the human body. Both deficiency and excess intake of iodide can lead to serious health issues, such as thyroid disease. Selecting iodide ions among anions has been a significant challenge for decades due to interference from other anions. In this study, we designed and synthesized a new pincer-type acridine–triazole fluorescent probe (probe 1) with an acridine ring as a spacer and a triazole as a linking arm attached to two naphthol groups. This probe can selectively recognize iodide ions in a mixed solvent of THF/H2O (v/v, 9/1), changing its color from colorless to light yellow, making it suitable for highly sensitive and selective colorimetric and fluorescent detection in water systems. We also synthesized another molecular tweezer-type acridine–triazole fluorescent probe (probe 2) that exhibits uniform detection characteristics for iodide ions in the acetonitrile system. Interestingly, compared to probe 2, probe 1 can be detected by the naked eye due to its circulation effect, providing a simple method for iodine detection. The detection limit of probe 1 is determined to be 10−8 mol·L−1 by spectrometric titration and isothermal titration calorimetry measurements. The binding stoichiometry between probe 1 and iodide ions is calculated to be 1:1 by these methods, and the binding constant is 2 × 105 mol·L−1. Full article
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19 pages, 11135 KiB  
Article
A Comparative Study of New Fluorescent Anthraquinone and Benzanthrone α-Aminophosphonates: Synthesis, Spectroscopy, Toxicology, X-ray Crystallography, and Microscopy of Opisthorchis felineus
by Armands Maļeckis, Marija Cvetinska, Muza Kirjušina, Ligita Mežaraupe, Sanita Kecko, Inese Gavarāne, Vladimir Kiyan, Lyudmila Lider, Veronika Pavlova, Marina Savicka, Sergey Belyakov and Elena Kirilova
Molecules 2024, 29(5), 1143; https://doi.org/10.3390/molecules29051143 - 04 Mar 2024
Viewed by 509
Abstract
In this research, we explore the synthesis of and characterize α-aminophosphonates derived from anthraquinone and benzanthrone, focusing on their fluorescence properties and potential applications in confocal laser scanning microscopy (CLSM). The synthesized compounds exhibit notable solvatochromic behavior, emitting fluorescence from green to red [...] Read more.
In this research, we explore the synthesis of and characterize α-aminophosphonates derived from anthraquinone and benzanthrone, focusing on their fluorescence properties and potential applications in confocal laser scanning microscopy (CLSM). The synthesized compounds exhibit notable solvatochromic behavior, emitting fluorescence from green to red across various solvents. Spectroscopic analysis, including 1H-, 13C-, and 31P-NMR, FTIR, and mass spectrometry, confirms the chemical structures. The compounds’ toxicity is evaluated using etiolated wheat sprouts, revealing varying degrees of impact on growth and oxidative damage. Furthermore, the study introduces these α-aminophosphonates for CLSM imaging of the parasitic flatworm Opisthorchis felineus, demonstrating their potential in visualizing biological specimens. Additionally, an X-ray crystallographic study of an anthraquinone α-aminophosphonate provides valuable structural insights. Full article
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17 pages, 23200 KiB  
Article
A Novel Fluorescence Probe Based on Azamonardine for Detecting and Imaging Cysteine in Cells and Zebrafish with High Selectivity and Sensitivity
by Yixu Zhao, Ting Wang, Ahmed Mohammed Ali Abdulkhaleq, Zhongfu Zuo, Yongjin Peng and Xibin Zhou
Molecules 2023, 28(17), 6246; https://doi.org/10.3390/molecules28176246 - 25 Aug 2023
Viewed by 819
Abstract
A novel fluorescent probe based on azamonardine (Aza) fluorophore was designed and synthesized for the highly selective detection of cysteine (Cys) in vivo and in vitro. After reacting with acryloyl chloride, the fluorescence of Aza is effectively quenched, resulting in the formation of [...] Read more.
A novel fluorescent probe based on azamonardine (Aza) fluorophore was designed and synthesized for the highly selective detection of cysteine (Cys) in vivo and in vitro. After reacting with acryloyl chloride, the fluorescence of Aza is effectively quenched, resulting in the formation of the Aza-acryl probe. Upon the addition of Cys, the ester bond of Aza-acryl is cleaved, releasing a new compound (Compound 1) with strong fluorescence, thereby achieving fluorescence turn-on detection of Cys. The structure of Aza-acryl was characterized using X-ray crystallography and NMR spectroscopy. Additionally, density functional theory was employed to elucidate the quenching mechanism of the acyl group on the Aza. Aza-acryl exhibits high selectivity towards Cys and distinguishes it from other biothiols such as homocysteine (Hcy) and glutathione (GSH). The mechanism of Aza-acryl for detecting Cys was investigated through HPLC, NMR spectroscopy, high-resolution mass spectrometry, and reaction kinetics experiments. Aza-acryl demonstrates excellent imaging capabilities for Cys in cells and zebrafish, providing a reliable and selectable tool for the detection and imaging of Cys in biological systems. Full article
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13 pages, 5549 KiB  
Article
Reversible Luminescent Switching Induced by Heat/Water Treatment in a Zero-Dimensional Hybrid Antimony(Ⅲ) Chloride
by Ying-Chen Peng, Hao-Wei Lin, Sheng-Hua Zhou, Jian-Ce Jin, Ting-Hui Zhuang, Abdusalam Ablez, Ze-Ping Wang, Ke-Zhao Du and Xiao-Ying Huang
Molecules 2023, 28(4), 1978; https://doi.org/10.3390/molecules28041978 - 19 Feb 2023
Cited by 6 | Viewed by 1920
Abstract
Recently zero-dimensional (0-D) inorganic–organic metal halides (IOMHs) have become a promising class of optoelectronic materials. Herein, we report a new photoluminescent (PL) 0-D antimony(III)-based IOMH single crystal, namely [H2BPZ][SbCl5]·H2O (BPZ = benzylpiperazine). Photophysical characterizations indicate that [H [...] Read more.
Recently zero-dimensional (0-D) inorganic–organic metal halides (IOMHs) have become a promising class of optoelectronic materials. Herein, we report a new photoluminescent (PL) 0-D antimony(III)-based IOMH single crystal, namely [H2BPZ][SbCl5]·H2O (BPZ = benzylpiperazine). Photophysical characterizations indicate that [H2BPZ][SbCl5]·H2O exhibits singlet/triplet dual-band emission. Density functional theory (DFT) calculations suggest that [H2BPZ][SbCl5]·H2O has the large energy difference between singlet and triplet states, which might induce the dual emission in this compound. Temperature-dependent PL spectra analyses suggest the soft lattice and strong electron–phonon coupling in this compound. Thermogravimetric analysis shows that the water molecules in the lattice of the title crystal could be removed by thermal treatment, giving rise to a dehydrated phase of [H2BPZ][SbCl5]. Interestingly, such structural transformation is accompanied by a reversible PL emission transition between red light (630 nm, dehydrated phase) and yellow light (595 nm, water-containing phase). When being exposed to an environment with 77% relative humidity, the emission color of the dehydrated phase was able to change from red to yellow within 20 s, and the red emission could be restored after reheating. The red to yellow emission switching could be achieved in acetone with water concentration as low as 0.2 vol%. The reversible PL transition phenomenon makes [H2BPZ][SbCl5]·H2O a potential material for luminescent water-sensing. Full article
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13 pages, 3016 KiB  
Article
GSH-Activatable Aggregation-Induced Emission Cationic Lipid for Efficient Gene Delivery
by Yue-Rui Yuan, Qiang Liu, Deyu Wang, Yu-Dan Deng, Ting-Ting Du, Wen-Jing Yi and Sheng-Tao Yang
Molecules 2023, 28(4), 1645; https://doi.org/10.3390/molecules28041645 - 08 Feb 2023
Cited by 2 | Viewed by 1491
Abstract
The key to gene therapy is the design of biocompatible and efficient delivery systems. In this work, a glutathione (GSH)-activated aggregation-induced-emission (AIE) cationic amphiphilic lipid, termed QM-SS-KK, was prepared for nonviral gene delivery. QM-SS-KK was composed of a hydrophilic biocompatible lysine tripeptide headgroup, [...] Read more.
The key to gene therapy is the design of biocompatible and efficient delivery systems. In this work, a glutathione (GSH)-activated aggregation-induced-emission (AIE) cationic amphiphilic lipid, termed QM-SS-KK, was prepared for nonviral gene delivery. QM-SS-KK was composed of a hydrophilic biocompatible lysine tripeptide headgroup, a GSH-triggered disulfide linkage, and a hydrophobic AIE fluorophore QM-OH (QM: quinoline-malononitrile) tail. The peptide moiety could not only efficiently compact DNA but also well modulate the dispersion properties of QM-SS-KK, leading to the fluorescence-off state before GSH treatment. The cleavage of disulfide in QM-SS-KK by GSH generated AIE signals in situ with a tracking ability. The liposomes consisted of QM-SS-KK, and 1,2-dioleoylphosphatidylethanolamine (DOPE) (QM-SS-KK/DOPE) delivered plasmid DNAs (pDNAs) into cells with high efficiency. In particular, QM-SS-KK/DOPE had an enhanced transfection efficiency (TE) in the presence of 10% serum, which was two times higher than that of the commercial transfection agent PEI25K. These results highlighted the great potential of peptide and QM-based fluorescence AIE lipids for gene delivery applications. Full article
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12 pages, 3932 KiB  
Article
A Novel Near-Infrared Ytterbium Complex [Yb(DPPDA)2](DIPEA) with Φ = 0.46% and τobs = 105 μs
by Guozhu Ren, Danyang Zhang, Hao Wang, Xiaofang Li, Ruiping Deng, Shihong Zhou, Long Tian and Liang Zhou
Molecules 2023, 28(4), 1632; https://doi.org/10.3390/molecules28041632 - 08 Feb 2023
Viewed by 1578
Abstract
The luminescent performances of near-infrared (NIR) lanthanide (Ln) complexes were restricted greatly by vibration quenching of X-H (X = C, N, O) oscillators, which are usually contained in ligands and solvents. Encapsulating Ln3+ into a cavity of coordination atoms is a feasible [...] Read more.
The luminescent performances of near-infrared (NIR) lanthanide (Ln) complexes were restricted greatly by vibration quenching of X-H (X = C, N, O) oscillators, which are usually contained in ligands and solvents. Encapsulating Ln3+ into a cavity of coordination atoms is a feasible method of alleviating this quenching effect. In this work, a novel ytterbium complex [Yb(DPPDA)2](DIPEA) coordinated with 4,7-diphenyl-1,10-phenanthroline-2,9-dicarboxylic acid (DPPDA) was synthesized and characterized by FT-IR, ESI-MS and elemental analysis. Under the excitation of 335 nm light, [Yb(DPPDA)2](DIPEA) showed two emission peaks at 975 and 1011 nm, respectively, which were assigned to the characteristic 2F5/22F7/2 transition of Yb3+. Meanwhile, this ytterbium complex exhibited a plausible absolute quantum yield of 0.46% and a luminescent lifetime of 105 μs in CD3OD solution. In particular, its intrinsic quantum yield was calculated to be 12.5%, and this considerably high value was attributed to the near-zero solvent molecules bound to Yb3+ and the absence of X-H oscillators in the first coordination sphere. Based on experimental results, we further proposed that the sensitized luminescence of [Yb(DPPDA)2](DIPEA) occurred via an internal redox mechanism instead of an energy transfer process. Full article
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15 pages, 4973 KiB  
Article
Dextran Fluorescent Probes Containing Sulfadiazine and Rhodamine B Groups
by Bi-Jie Bie, Xiao-Rui Zhao, Jia-Rui Yan, Xi-Jun Ke, Fan Liu and Guo-Ping Yan
Molecules 2022, 27(19), 6747; https://doi.org/10.3390/molecules27196747 - 10 Oct 2022
Cited by 4 | Viewed by 1608
Abstract
Fluorescent imaging has been expanded, as a non-invasive diagnostic modality for cancers, in recent years. Fluorescent probes in the near-infrared window can provide high sensitivity, resolution, and signal-to-noise ratio, without the use of ionizing radiation. Some fluorescent compounds with low molecular weight, such [...] Read more.
Fluorescent imaging has been expanded, as a non-invasive diagnostic modality for cancers, in recent years. Fluorescent probes in the near-infrared window can provide high sensitivity, resolution, and signal-to-noise ratio, without the use of ionizing radiation. Some fluorescent compounds with low molecular weight, such as rhodamine B (RhB) and indocyanine green (ICG), have been used in fluorescent imaging to improve imaging contrast and sensitivity; however, since these probes are excreted from the body quickly, they possess significant restrictions for imaging. To find a potential solution to this, this work investigated the synthesis and properties of novel macromolecular fluorescent compounds. Herein, water-soluble dextran fluorescent compounds (SD-Dextran-RhB) were prepared by the attachment of RhB and sulfadiazine (SD) derivatives to dextran carrier. These fluorescent compounds were then characterized through IR, 1H NMR, 13C NMR, UV, GPC, and other methods. Assays of their cellular uptake and cell cytotoxicity and fluorescent imaging were also performed. Through this study, it was found that SD-Dextran-RhB is sensitive to acidic conditions and possesses low cell cytotoxicities compared to normal 293 cells and HepG2 and HeLa tumor cells. Moreover, SD-Dextran-RhB demonstrated good fluorescent imaging in HepG2 and HeLa cells. Therefore, SD-Dextran-RhB is suitable to be potentially applied as a probe in the fluorescent imaging of tumors. Full article
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13 pages, 2602 KiB  
Article
Partnered Excited-State Intermolecular Proton Transfer Fluorescence (P-ESIPT) Signaling for Nitrate Sensing and High-Resolution Cell-Imaging
by Pan Ma, Fuchun Gong, Hanming Zhu, You Qian, Lingzhi He, Jiaoyun Xia and Zhong Cao
Molecules 2022, 27(16), 5164; https://doi.org/10.3390/molecules27165164 - 13 Aug 2022
Cited by 4 | Viewed by 1611
Abstract
Nitrite (NO2) is a common pollutant and is widely present in the environment and in human bodies. The development of a rapid and accurate method for NO2 detection is always a very important task. Herein, we synthesized a [...] Read more.
Nitrite (NO2) is a common pollutant and is widely present in the environment and in human bodies. The development of a rapid and accurate method for NO2 detection is always a very important task. Herein, we synthesized a partnered excited-state intermolecular proton transfer (ESIPT) fluorophore using the “multi-component one pot” method, and used this as a probe (ESIPT-F) for sensing NO2. ESIPT-F exhibited bimodal emission in different solvents because of the solvent-mediated ESIPT reaction. The addition of NO2 caused an obvious change in colors and tautomeric fluorescence due to the graft of NO2 into the ESIPT-F molecules. From this basis, highly sensitive and selective analysis of NO2 was developed using tautomeric emission signaling, achieving sensitive detection of NO2 in the concentration range of 0~45 mM with a detection limit of 12.5 nM. More importantly, ESIPT-F showed the ability to anchor proteins and resulted in a recognition-driven “on-off” ESIPT process, enabling it to become a powerful tool for fluorescence imaging of proteins or protein-based subcellular organelles. MTT experimental results revealed that ESIPT-F is low cytotoxic and has good membrane permeability to cells. Thus, ESIPT-F was further employed to image the tunneling nanotube in vitro HEC-1A cells, displaying high-resolution performance. Full article
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Review

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19 pages, 8933 KiB  
Review
A Review for In Vitro and In Vivo Detection and Imaging of Gaseous Signal Molecule Carbon Monoxide by Fluorescent Probes
by Can Xie, Kun Luo, Libin Tan, Qiaomei Yang, Xiongjie Zhao and Liyi Zhou
Molecules 2022, 27(24), 8842; https://doi.org/10.3390/molecules27248842 - 13 Dec 2022
Cited by 4 | Viewed by 1817
Abstract
Carbon monoxide (CO) is a vital endogenous gaseous transmitter molecule involved in the regulation of various physiological and pathological processes in living biosystems. In order to investigate the biological function of CO, many technologies have been developed to monitor the level of endogenous [...] Read more.
Carbon monoxide (CO) is a vital endogenous gaseous transmitter molecule involved in the regulation of various physiological and pathological processes in living biosystems. In order to investigate the biological function of CO, many technologies have been developed to monitor the level of endogenous CO in biosystems. Among them, the fluorescence detection technology based on the fluorescent probe has the advantages of high sensitivity, excellent selectivity, simple operation, especially non-invasive damage to biological samples, and the possibility of real-time in situ detection, etc., which is considered to be one of the most effective and applicable detection techniques. Therefore, in the last few years, a lot of work has been carried out on the design, synthesis and in vivo fluorescence imaging studies of CO fluorescent probes. Furthermore, using fluorescent probes to detect the changes in CO concentrations in living cells and tissues as well as in organisms has been one of the hot research topics in recent years. However, it is still a challenge to rationally design CO fluorescent probe with excellent optical performance, structural stability, low background interference, good biocompatibility, and excellent water solubility. Therefore, this review focuses on the research progress of CO fluorescent probes in the detection mechanism and biological applications in recent years. However, this popular and leading topic has rarely been summarized comprehensively to date. Thus, the research progress of CO fluorescent probes in recent years is reviewed in terms of their design concept, detection mechanism, and their biological applications. In addition, the relationship between the structure and performance of the probes was also discussed. More significantly, we hope that more excellent optical properties fluorescent probes for gaseous transmitter molecule CO detection and imaging will overcome the current problems of high biotoxicity and limited water solubility in future. Full article
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21 pages, 8244 KiB  
Review
Fluorescent Organic Small Molecule Probes for Bioimaging and Detection Applications
by Yufei Yang, Fucheng Gao, Yandong Wang, Hui Li, Jie Zhang, Zhiwei Sun and Yanyan Jiang
Molecules 2022, 27(23), 8421; https://doi.org/10.3390/molecules27238421 - 01 Dec 2022
Cited by 19 | Viewed by 3406
Abstract
The activity levels of key substances (metal ions, reactive oxygen species, reactive nitrogen, biological small molecules, etc.) in organisms are closely related to intracellular redox reactions, disease occurrence and treatment, as well as drug absorption and distribution. Fluorescence imaging technology provides a visual [...] Read more.
The activity levels of key substances (metal ions, reactive oxygen species, reactive nitrogen, biological small molecules, etc.) in organisms are closely related to intracellular redox reactions, disease occurrence and treatment, as well as drug absorption and distribution. Fluorescence imaging technology provides a visual tool for medicine, showing great potential in the fields of molecular biology, cellular immunology and oncology. In recent years, organic fluorescent probes have attracted much attention in the bioanalytical field. Among various organic fluorescent probes, fluorescent organic small molecule probes (FOSMPs) have become a research hotspot due to their excellent physicochemical properties, such as good photostability, high spatial and temporal resolution, as well as excellent biocompatibility. FOSMPs have proved to be suitable for in vivo bioimaging and detection. On the basis of the introduction of several primary fluorescence mechanisms, the latest progress of FOSMPs in the applications of bioimaging and detection is comprehensively reviewed. Following this, the preparation and application of fluorescent organic nanoparticles (FONPs) that are designed with FOSMPs as fluorophores are overviewed. Additionally, the prospects of FOSMPs in bioimaging and detection are discussed. Full article
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