molecules-logo

Journal Browser

Journal Browser

Synthesis and Applications of Near-Infrared (NIR) Organic Fluorophores

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

Deadline for manuscript submissions: closed (31 August 2023) | Viewed by 11508

Special Issue Editors

Department of Chemistry and Environmental Science, College of Science and Liberal Arts, New Jersey Institute of Technology, 323 Martin Luther King Jr. Blvd., Newark, NJ 07102, USA
Interests: organic chemistry; fluorescent probe; bioimaging; NIR-light-responsive chromophores; biomaterials
College of chemistry, Nankai University, Tianjin, China
Interests: physical organic chemistry; triplet photosensitizer; photodynamic therapy; photoredox catalysis

Special Issue Information

Dear Colleague,

Near-infrared (NIR) fluorophores are indispensable for applications in bioimaging, biosensing, and therapeutics. The long wavelengths allow deeper tissue penetration with minimal photon damage, both of which are urgently needed for biological studies and medical treatments. In the clinic, several NIR fluorophores have been approved or under trial by the US Food and Drug Administration (FDA), including indocyanine (ICG) and methylene blue (MB). In biological research, a variety of NIR fluorophores are commercially available and ready for conjugation with biomolecules for targeting purposes. With the imaging technique, NIR fluorophores and probes have been in a great position for high imaging resolution; however, challenges remain to the design and synthesis of optimized structures that meet the need of fast-revolving microscopy technology. To date, many NIR fluorophores have been designed and synthesized with spectacular properties, such as large stock shifts, high quantum yields, biocompatibility, water solubility, two-photon cross-sections, and energy transfer potentials.

Dr. Yuanwei Zhang
Dr. Ling Huang
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access semimonthly journal published by MDPI.

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

  • near-infrared
  • organic fluorophores
  • bio-imaging
  • two-photon
  • fluorescent probes
  • energy transfer
  • aggregation-induced emission

Published Papers (6 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Jump to: Review

11 pages, 2191 KiB  
Article
Bodipy Dimer for Enhancing Triplet-Triplet Annihilation Upconversion Performance
by Min Gao, Le Zeng, Linhan Jiang, Mingyu Zhang, Yong Chen and Ling Huang
Molecules 2023, 28(14), 5474; https://doi.org/10.3390/molecules28145474 - 18 Jul 2023
Viewed by 1170
Abstract
Triplet-triplet annihilation upconversion (TTA-UC) has considerable potential for emerging applications in bioimaging, optogenetics, photoredox catalysis, solar energy harvesting, etc. Fluoroboron dipyrrole (Bodipy) dyes are an essential type of annihilator in TTA-UC. However, conventional Bodipy dyes generally have large molar extinction coefficients and small [...] Read more.
Triplet-triplet annihilation upconversion (TTA-UC) has considerable potential for emerging applications in bioimaging, optogenetics, photoredox catalysis, solar energy harvesting, etc. Fluoroboron dipyrrole (Bodipy) dyes are an essential type of annihilator in TTA-UC. However, conventional Bodipy dyes generally have large molar extinction coefficients and small Stokes shifts (<20 nm), subjecting them to severe internal filtration effects at high concentrations, and resulting in low upconversion quantum efficiency of TTA-UC systems using Bodipy dyes as annihilators. In this study, a Bodipy dimer (B-2) with large Stokes shifts was synthesized using the strategy of dimerization of an already reported Bodipy annihilator (B-1). Photophysical characterization and theoretical chemical analysis showed that both B-1 and B-2 can couple with the red light-activated photosensitizer PdTPBP to fulfill TTA-UC; however, the higher fluorescence quantum yield of B-2 resulted in a higher upconversion efficiency (ηUC) for PdTPBP/B-2 (10.7%) than for PdTPBP/B-1 (4.0%). This study proposes a new strategy to expand Bodipy Stokes shifts and improve TTA-UC performance, which can facilitate the application of TTA-UC in photonics and biophotonics. Full article
Show Figures

Figure 1

9 pages, 2603 KiB  
Article
A Near-Infrared Fluorescent Probe for Recognition of Hypochlorite Anions Based on Dicyanoisophorone Skeleton
by Chang-Xiang Liu, Shu-Yuan Xiao, Xiu-Lin Gong, Xi Zhu, Ya-Wen Wang and Yu Peng
Molecules 2023, 28(1), 402; https://doi.org/10.3390/molecules28010402 - 03 Jan 2023
Cited by 8 | Viewed by 1626
Abstract
A novel near-infrared (NIR) fluorescent probe (SWJT-9) was designed and synthesized for the detection of hypochlorite anion (ClO) using a diaminomaleonitrile group as the recognition site. SWJT-9 had large Stokes shift (237 nm) and showed an excellent NIR fluorescence [...] Read more.
A novel near-infrared (NIR) fluorescent probe (SWJT-9) was designed and synthesized for the detection of hypochlorite anion (ClO) using a diaminomaleonitrile group as the recognition site. SWJT-9 had large Stokes shift (237 nm) and showed an excellent NIR fluorescence response to ClO with the color change under the visible light. It showed a low detection limit (24.7 nM), high selectivity, and rapid detection (within 2 min) for ClO. The new detection mechanism of SWJT-9 on ClO was confirmed by 1H NMR, MS spectrum, and the density functional theory (DFT) calculations. In addition, the probe was successfully used to detect ClO in HeLa cells. Full article
Show Figures

Figure 1

14 pages, 3267 KiB  
Article
Water-Soluble Single-Benzene Chromophores: Excited State Dynamics and Fluorescence Detection
by Yingge Fan, Jin Ma, Huijing Liu and Taihong Liu
Molecules 2022, 27(17), 5522; https://doi.org/10.3390/molecules27175522 - 27 Aug 2022
Cited by 3 | Viewed by 1674
Abstract
Two water-soluble single-benzene-based chromophores, 2,5-di(azetidine-1-yl)-tereph- thalic acid (DAPA) and its disodium carboxylate (DAP-Na), were conveniently obtained. Both chromophores preserved moderate quantum yields in a wide range of polar and protonic solvents. Spectroscopic studies demonstrated that DAPA exhibited red luminescence [...] Read more.
Two water-soluble single-benzene-based chromophores, 2,5-di(azetidine-1-yl)-tereph- thalic acid (DAPA) and its disodium carboxylate (DAP-Na), were conveniently obtained. Both chromophores preserved moderate quantum yields in a wide range of polar and protonic solvents. Spectroscopic studies demonstrated that DAPA exhibited red luminescence as well as large Stokes shift (>200 nm) in aqueous solutions. Femtosecond transient absorption spectra illustrated quadrupolar DAPA usually involved the formation of an intramolecular charge transfer state. Its Frank–Condon state could be rapidly relaxed to a slight symmetry-breaking state upon light excitation following the solvent relaxation, then the slight charge separation may occur and the charge localization became partially asymmetrical in polar environments. Density functional theory (DFT) calculation results were supported well with the experimental measurements. Unique pH-dependent fluorescent properties endows the two chromophores with rapid, highly selective, and sensitive responses to the amino acids in aqueous media. In detail, DAPA served as a fluorescence turn-on probe with a detection limit (DL) of 0.50 μM for Arg and with that of 0.41 μM for Lys. In contrast, DAP-Na featured bright green luminescence and showed fluorescence turn-off responses to Asp and Glu with the DLs of 0.12 μM and 0.16 μM, respectively. Meanwhile, these two simple-structure probes exhibited strong anti-interference ability towards other natural amino acids and realized visual identification of specific analytes. The present work helps to understand the photophysic–structure relationship of these kinds of compounds and render their fluorescent detection applications. Full article
Show Figures

Figure 1

11 pages, 10189 KiB  
Article
Direct Utilization of Near-Infrared Light for Photooxidation with a Metal-Free Photocatalyst
by Le Zeng, Zhonghe Wang, Tiexin Zhang and Chunying Duan
Molecules 2022, 27(13), 4047; https://doi.org/10.3390/molecules27134047 - 23 Jun 2022
Cited by 5 | Viewed by 1965
Abstract
Near-infrared (NIR) light-triggered photoredox catalysis is highly desirable because NIR light occupies almost 50% of solar energy and possesses excellent penetrating power in various media. Herein we utilize a metal-free boron dipyrromethene (BODIPY) derivative as the photocatalyst to achieve NIR light (720 nm [...] Read more.
Near-infrared (NIR) light-triggered photoredox catalysis is highly desirable because NIR light occupies almost 50% of solar energy and possesses excellent penetrating power in various media. Herein we utilize a metal-free boron dipyrromethene (BODIPY) derivative as the photocatalyst to achieve NIR light (720 nm LED)–driven oxidation of benzylamine derivatives, sulfides, and aryl boronic acids. Compared to blue light–driven photooxidation using Ru(bpy)3Cl2 as a photocatalyst, NIR light–driven photooxidation exhibited solvent independence and superior performance in large-volume (20 mL) reaction, presumably thanks to the neutral structure of a BODIPY photocatalyst and the deeper penetration depth of NIR light. We further demonstrate the application of this metal-free NIR photooxidation to prodrug activation and combination with Cu-catalysis for cross coupling reaction, exhibiting the potential of metal-free NIR photooxidation as a toolbox for organic synthesis and drug development. Full article
Show Figures

Graphical abstract

Review

Jump to: Research

30 pages, 7083 KiB  
Review
Medical Applications and Advancement of Near Infrared Photosensitive Indocyanine Green Molecules
by Zulpya Mahmut, Chunmei Zhang, Fei Ruan, Nan Shi, Xinyao Zhang, Yuda Wang, Xianhong Zheng, Zixin Tang, Biao Dong, Donghui Gao and Jiao Sun
Molecules 2023, 28(16), 6085; https://doi.org/10.3390/molecules28166085 - 16 Aug 2023
Cited by 2 | Viewed by 1741
Abstract
Indocyanine green (ICG) is an important kind of near infrared (NIR) photosensitive molecules for PTT/PDT therapy as well as imaging. When exposed to NIR light, ICG can produce reactive oxygen species (ROS), which can kill cancer cells and pathogenic bacteria. Moreover, the absorbed [...] Read more.
Indocyanine green (ICG) is an important kind of near infrared (NIR) photosensitive molecules for PTT/PDT therapy as well as imaging. When exposed to NIR light, ICG can produce reactive oxygen species (ROS), which can kill cancer cells and pathogenic bacteria. Moreover, the absorbed light can also be converted into heat by ICG molecules to eliminate cancer cells. In addition, it performs exceptionally well in optical imaging-guided tumor therapy and antimicrobial therapy due to its deeper tissue penetration and low photobleaching properties in the near-infrared region compared to other dyes. In order to solve the problems of water and optical stability and multi-function problem of ICG molecules, composite nanomaterials based on ICG have been designed and widely used, especially in the fields of tumors and sterilization. So far, ICG molecules and their composite materials have become one of the most famous infrared sensitive materials. However, there have been no corresponding review articles focused on ICG molecules. In this review, the molecular structure and properties of ICG, composite material design, and near-infrared light- triggered anti-tumor, and antibacterial, and clinical applications are reviewed in detail, which of great significance for related research. Full article
Show Figures

Figure 1

20 pages, 4808 KiB  
Review
Recent Progress on NIR Fluorescent Probes for Enzymes
by Jintao Zhao, Tao Ma, Bingbing Chang and Jianguo Fang
Molecules 2022, 27(18), 5922; https://doi.org/10.3390/molecules27185922 - 12 Sep 2022
Cited by 10 | Viewed by 2524
Abstract
The majority of diseases’ biomarkers are enzymes, and the regulation of enzymes is fundamental but crucial. Biological system disorders and diseases can result from abnormal enzymatic activity. Given the biological significance of enzymes, researchers have devised a plethora of tools to map the [...] Read more.
The majority of diseases’ biomarkers are enzymes, and the regulation of enzymes is fundamental but crucial. Biological system disorders and diseases can result from abnormal enzymatic activity. Given the biological significance of enzymes, researchers have devised a plethora of tools to map the activity of particular enzymes in order to gain insight regarding their function and distribution. Near-infrared (NIR) fluorescence imaging studies on enzymes may help to better understand their roles in living systems due to their natural imaging advantages. We review the NIR fluorescent probe design strategies that have been attempted by researchers to develop NIR fluorescent sensors of enzymes, and these works have provided deep and intuitive insights into the study of enzymes in biological systems. The recent enzyme-activated NIR fluorescent probes and their applications in imaging are summarized, and the prospects and challenges of developing enzyme-activated NIR fluorescent probes are discussed. Full article
Show Figures

Figure 1

Back to TopTop