Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging

A special issue of Biosensors (ISSN 2079-6374). This special issue belongs to the section "Biosensor Materials".

Deadline for manuscript submissions: closed (31 May 2023) | Viewed by 32301

Special Issue Editors


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Guest Editor
School of Biomedical Engineering, Hainan University, Haikou, China
Interests: fluorescent material; luminescence material; fluorescent probe; fluorescent sensor; biosensor; fluorescent imaging; bioimaging; photosensitizer
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Guest Editor
School of Biomedical Engineering, Hainan University, Haikou, China
Interests: fluorescent material; luminescence material; fluorescent probe; fluorescent sensor; biosensor; fluorescent imaging; bioimaging; photosensitizer
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Guest Editor
Institute of Neuroregeneration and Neurorehabilitation, Qingdao University, Qingdao 266071, China
Interests: fluorescent material; luminescence material; fluorescent probe; fluorescent sensor; biosensor; fluorescent imaging; bioimaging; photosensitizer
Special Issues, Collections and Topics in MDPI journals
Qingdao Haiwan Science and Technology Industry Research Institute Co., Ltd., Qingdao, China
Interests: fluorescent material; luminescence material; fluorescent probe; fluorescent sensor; biosensor; fluorescent imaging; bioimaging; photosensitizer
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Fluorescent material is an extensively studied issue in  the bio-field because it is easy to functionalize and tune fluorescence color. In previous decades, major progress in the synthesis, characterization, and application of fluorescent materials has been accomplished, along with the recent development of nano-, biobased, sensor, imaging and high performance material-based technologies. These advanced technologies promote the application of fluorescent materials in a wide range of applications, for instance, bio-sensing, bio-labelling, bio-tracing, bio-imaging, diseases diagnosis and therapy, etc. To advance the use of fluorescent materials in the bio-field, the development of biocompatible fluorescent materials (BFM) has become increasingly relevant. The intention of this research topic is to describe the biocompatible fluorescent materials (BFM), the recent breakthroughs in this field, and their application in the bio-field. Our attention will be focused on: (i) the preparation of biocompatible fluorescent materials (BFM), including material synthesis and purification and photo physical chemical properties; (ii) the fabrication of novel fluorescent detection devices for bio-objects; and (iii) applications in bio-field, bio-sensing, bio-tracing, bio-imaging and diseases diagnosis and therapy, etc. We hope that this research topic will attract the attention of academic and industrial researchers who are interested in the development of biocompatible fluorescent materials (BFM) and their biological applications. Our goal is to stimulate ideas, methods, and technologies related to chemistry, biology, materials science, medicine, bioscience and electronics in this exciting area.

We welcome manuscripts from diverse aspects of fluorescent materials, including but not limited to:

  • Synthesis and design of novel fluorescent materials with excellent biocompatibility;
  • Preparation of fluorescent materials, including materials synthesis and purification;
  • Multi-scale techniques and morphological studies on biocompatible fluorescent materials;
  • Investigation of fluorescent materials structure-property relationships;
  • Applications in cell-labelling, tumor labelling and therapy, bio-sensing, bio-imaging, etc.;
  • the fabrication of novel fluorescent detection devices for bio-object.

Dr. Yalong Wang
Prof. Dr. Mingqiang Zhu
Dr. Deteng Zhang
Dr. Meng Zheng
Guest Editors

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Keywords

  • fluorescent material
  • luminescence material
  • fluorescent probe
  • fluorescent sensor
  • biosensor
  • fluorescent imaging
  • bioimaging
  • photosensitizer

Published Papers (17 papers)

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Editorial

Jump to: Research, Review

3 pages, 201 KiB  
Editorial
Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging
by Meng Zheng, Yalong Wang, Deteng Zhang and Mingqiang Zhu
Biosensors 2023, 13(10), 906; https://doi.org/10.3390/bios13100906 - 26 Sep 2023
Viewed by 1168
Abstract
Fluorescent materials have great potential for use in biomedical applications due to their ease of functionalization and tunable fluorescence color [...] Full article

Research

Jump to: Editorial, Review

12 pages, 10313 KiB  
Article
A Ratiometric Fluorescent Probe for Hypochlorite and Lipid Droplets to Monitor Oxidative Stress
by Mousumi Baruah, Anal Jana, Niharika Pareek, Shikha Singh and Animesh Samanta
Biosensors 2023, 13(6), 662; https://doi.org/10.3390/bios13060662 - 17 Jun 2023
Cited by 3 | Viewed by 1846
Abstract
Mitochondria are valuable subcellular organelles and play crucial roles in redox signaling in living cells. Substantial evidence proved that mitochondria are one of the critical sources of reactive oxygen species (ROS), and overproduction of ROS accompanies redox imbalance and cell immunity. Among ROS, [...] Read more.
Mitochondria are valuable subcellular organelles and play crucial roles in redox signaling in living cells. Substantial evidence proved that mitochondria are one of the critical sources of reactive oxygen species (ROS), and overproduction of ROS accompanies redox imbalance and cell immunity. Among ROS, hydrogen peroxide (H2O2) is the foremost redox regulator, which reacts with chloride ions in the presence of myeloperoxidase (MPO) to generate another biogenic redox molecule, hypochlorous acid (HOCl). These highly reactive ROS are the primary cause of damage to DNA (deoxyribonucleic acid), RNA (ribonucleic acid), and proteins, leading to various neuronal diseases and cell death. Cellular damage, related cell death, and oxidative stress are also associated with lysosomes which act as recycling units in the cytoplasm. Hence, simultaneous monitoring of multiple organelles using simple molecular probes is an exciting area of research that is yet to be explored. Significant evidence also suggests that oxidative stress induces the accumulation of lipid droplets in cells. Hence, monitoring redox biomolecules in mitochondria and lipid droplets in cells may give a new insight into cell damage, leading to cell death and related disease progressions. Herein, we developed simple hemicyanine-based small molecular probes with a boronic acid trigger. A fluorescent probe AB that could efficiently detect mitochondrial ROS, especially HOCl, and viscosity simultaneously. When the AB probe released phenylboronic acid after reacting with ROS, the product AB–OH exhibited ratiometric emissions depending on excitation. This AB–OH nicely translocates to lysosomes and efficiently monitors the lysosomal lipid droplets. Photoluminescence and confocal fluorescence imaging analysis suggest that AB and corresponding AB–OH molecules are potential chemical probes for studying oxidative stress. Full article
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8 pages, 3210 KiB  
Communication
A Novel Fluorescent Probe for the Detection of Hydrogen Peroxide
by Kangkang Wang, Tingting Yao, Jiayu Xue, Yanqiu Guo and Xiaowei Xu
Biosensors 2023, 13(6), 658; https://doi.org/10.3390/bios13060658 - 16 Jun 2023
Cited by 4 | Viewed by 1986
Abstract
Hydrogen peroxide (H2O2) is one of the important reactive oxygen species (ROS), which is closely related to many pathological and physiological processes in living organisms. Excessive H2O2 can lead to cancer, diabetes, cardiovascular diseases, and other [...] Read more.
Hydrogen peroxide (H2O2) is one of the important reactive oxygen species (ROS), which is closely related to many pathological and physiological processes in living organisms. Excessive H2O2 can lead to cancer, diabetes, cardiovascular diseases, and other diseases, so it is necessary to detect H2O2 in living cells. Since this work designed a novel fluorescent probe to detect the concentration of H2O2, the H2O2 reaction group arylboric acid was attached to the fluorescein 3-Acetyl-7-hydroxycoumarin as a specific recognition group for the selective detection of hydrogen peroxide. The experimental results show that the probe can effectively detect H2O2 with high selectivity and measure cellular ROS levels. Therefore, this novel fluorescent probe provides a potential monitoring tool for a variety of diseases caused by H2O2 excess. Full article
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10 pages, 4890 KiB  
Communication
A Novel Aggregation-Induced Emission Fluorescent Probe for Detection of β-Amyloid Based on Pyridinyltriphenylamine and Quinoline–Malononitrile
by Yan Fang, Qi Wang, Chenlong Xiang, Guijin Liu and Junjian Li
Biosensors 2023, 13(6), 610; https://doi.org/10.3390/bios13060610 - 02 Jun 2023
Cited by 2 | Viewed by 1515
Abstract
β-amyloid is an important pathological feature of Alzheimer’s disease. Its abnormal production and aggregation in the patient’s brain is an important basis for the early diagnosis and confirmation of Alzheimer’s disease. In this study, a novel aggregation-induced emission fluorescent probe, PTPA-QM, was designed [...] Read more.
β-amyloid is an important pathological feature of Alzheimer’s disease. Its abnormal production and aggregation in the patient’s brain is an important basis for the early diagnosis and confirmation of Alzheimer’s disease. In this study, a novel aggregation-induced emission fluorescent probe, PTPA-QM, was designed and synthesized based on pyridinyltriphenylamine and quinoline–malononitrile. These molecules exhibit a donor–donor–π–acceptor structure with a distorted intramolecular charge transfer feature. PTPA-QM displayed the advantages of good selectivity toward viscosity. The fluorescence intensity of PTPA-QM in 99% glycerol solution was 22-fold higher than that in pure DMSO. PTPA-QM has been confirmed to have excellent membrane permeability and low toxicity. More importantly, PTPA-QM exhibits a high affinity towards β-amyloid in brain sections of 5XFAD mice and classical inflammatory cognitive impairment mice. In conclusion, our work provides a promising tool for the detection of β-amyloid. Full article
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13 pages, 2616 KiB  
Article
Surfactant-Assisted Label-Free Fluorescent Aptamer Biosensors and Binding Assays
by Hanxiao Zhang, Albert Zehan Li and Juewen Liu
Biosensors 2023, 13(4), 434; https://doi.org/10.3390/bios13040434 - 29 Mar 2023
Cited by 7 | Viewed by 1781
Abstract
Using DNA staining dyes such as SYBR Green I (SGI) and thioflavin T (ThT) to perform label-free detection of aptamer binding has been performed for a long time for both binding assays and biosensor development. Since these dyes are cationic, they can also [...] Read more.
Using DNA staining dyes such as SYBR Green I (SGI) and thioflavin T (ThT) to perform label-free detection of aptamer binding has been performed for a long time for both binding assays and biosensor development. Since these dyes are cationic, they can also adsorb to the wall of reaction vessels leading to unstable signals and even false interpretations of the results. In this work, the stability of the signal was first evaluated using ThT and the classic adenosine aptamer. In a polystyrene microplate, a drop in fluorescence was observed even when non-binding targets or water were added, whereas a more stable signal was achieved in a quartz cuvette. Equilibrating the system can also improve signal stability. In addition, a few polymers and surfactants were also screened, and 0.01% Triton X-100 was found to have the best protection effect against fluorescence signal decrease due to dye adsorption. Three aptamers for Hg2+, adenosine, and cortisol were tested for their sensitivity and signal stability in the absence and presence of Triton X-100. In each case, the sensitivity was similar, whereas the signal stability was better for the surfactant. This study indicates that careful control experiments need to be designed to ensure reliable results and that the reliability can be improved by using Triton X-100 and a long equilibration time. Full article
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17 pages, 3144 KiB  
Article
Response of Coccomyxa cimbrica sp.nov. to Increasing Doses of Cu(II) as a Function of Time: Comparison between Exposure in a Microfluidic Device or with Standard Protocols
by Riccardo Speghini, Carlo Buscato, Stefania Marcato, Ilaria Fortunati, Barbara Baldan and Camilla Ferrante
Biosensors 2023, 13(4), 417; https://doi.org/10.3390/bios13040417 - 23 Mar 2023
Cited by 2 | Viewed by 1272
Abstract
In this study, we explore how the in vitro conditions chosen to cultivate and observe the long-term (up to 72 h) toxic effect of Cu(II) on the freshwater microalga Coccomyxa cimbrica sp.nov. can affect the dose response in time. We test three different [...] Read more.
In this study, we explore how the in vitro conditions chosen to cultivate and observe the long-term (up to 72 h) toxic effect of Cu(II) on the freshwater microalga Coccomyxa cimbrica sp.nov. can affect the dose response in time. We test three different cultivation protocols: (i) under static conditions in sealed glass cells, (ii) in a microfluidic device, where the sample is constantly circulated with a peristaltic pump, and (iii) under continuous agitation in plastic falcons on an orbital shaker. The advantage and novelty of this study resides in the fact that each condition can mimic different environmental conditions that alga cells can find in nature. The effect of increasing dose of Cu(II) as a function of time (24, 48, and 72 h) is monitored following chlorophyll a fluorescence intensity from single cells. Fluorescence lifetime imaging experiments are also explored to gain information on the changes induced by Cu(II) in the photosynthetic cycle of this microalga. Full article
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17 pages, 5038 KiB  
Article
Fluorescent Nanocomposite Hydrogels Based on Conjugated Polymer Nanoparticles as Platforms for Alkaline Phosphatase Detection
by Yolanda Alacid, Rocío Esquembre, Francisco Montilla, María José Martínez-Tomé and C. Reyes Mateo
Biosensors 2023, 13(3), 408; https://doi.org/10.3390/bios13030408 - 21 Mar 2023
Cited by 1 | Viewed by 1891
Abstract
This work describes the development and characterization of fluorescent nanocomposite hydrogels, with high swelling and absorption capacity, and prepared using a green protocol. These fluorescent materials are obtained by incorporating, for the first time, polyfluorenes-based nanoparticles with different emission bands—poly[9,9-dioctylfluorenyl-2,7-diyl] (PFO) and poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(1,4-benzo-{2,1,3}-thiadiazole)] [...] Read more.
This work describes the development and characterization of fluorescent nanocomposite hydrogels, with high swelling and absorption capacity, and prepared using a green protocol. These fluorescent materials are obtained by incorporating, for the first time, polyfluorenes-based nanoparticles with different emission bands—poly[9,9-dioctylfluorenyl-2,7-diyl] (PFO) and poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(1,4-benzo-{2,1,3}-thiadiazole)] (F8BT)—into a three-dimensional polymeric network based on polyacrylamide. To this end, two strategies were explored: incorporation of the nanoparticles during the polymerization process (in situ) and embedment after the hydrogel formation (ex situ). The results show that the combination of PFO nanoparticles introduced by the ex situ method provided materials with good storage stability, homogeneity and reproducibility properties, allowing their preservation in the form of xerogel. The fluorescent nanocomposite hydrogels have been tested as a transportable and user-friendly sensing platform. In particular, the ability of these materials to specifically detect the enzyme alkaline phosphatase (ALP) has been evaluated as a proof-of-concept. The sensor was able to quantify the presence of the enzyme in an aqueous sample with a response time of 10 min and LOD of 21 nM. Given these results, we consider that this device shows great potential for quantifying physiological ALP levels as well as enzyme activity in environmental samples. Full article
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11 pages, 2294 KiB  
Communication
Rational Design of High-Performance Hemithioindigo-Based Photoswitchable AIE Photosensitizer and Enabling Reversible Control Singlet Oxygen Generation
by Junjie Wang, Jianshuang Wei, Yuehong Leng, Yanfeng Dai, Changqiang Xie, Zhihong Zhang, Mingqiang Zhu and Xingzhou Peng
Biosensors 2023, 13(3), 324; https://doi.org/10.3390/bios13030324 - 27 Feb 2023
Cited by 5 | Viewed by 1660
Abstract
A photosensitizer furnishing with reversible control singlet oxygen generation (1O2) is highly desirable for precise photodynamic therapy (PDT), lessening non-specific harm to healthy tissues. Here, a novel photoswitchable aggregation-induced emission (AIE) photosensitizer based on a triarylamine (TPA)-modified hemithioindigo (HTI), [...] Read more.
A photosensitizer furnishing with reversible control singlet oxygen generation (1O2) is highly desirable for precise photodynamic therapy (PDT), lessening non-specific harm to healthy tissues. Here, a novel photoswitchable aggregation-induced emission (AIE) photosensitizer based on a triarylamine (TPA)-modified hemithioindigo (HTI), 6Br-HTI-TPA-OMe, was rationally designed. The triarylamine AIE photosensitizing moiety and HTI switch unit were covalently linked in one molecule, permitting reversible regulation of 1O2 production. The photophysical evaluations revealed that 6Br-HTI-TPA-OMe possessed excellent AIE properties and Z/E photoswitch performance in different solvents. Additionally, the amphiphilic phospholipid-fabricated nanoparticles (NPs) also exhibited photochromic behavior in water. The Z-NPs initiated the generation of 1O2 upon 520 nm light-emitting diode (LED) irradiation, but after switching to E-NPs, the generation of 1O2 was inhibited by the competitive energy transfer, suggesting that reversible Z/E isomerization could photocontrol 1O2 generation. The in vitro anti-tumor experiment verified that the 6Br-HTI-TPA-OMe can act as a photoswitchable AIE photosensitizer. This is the first report on the photoswitchable AIE photosensitizer of HTI-based molecules, to the best of our knowledge. Full article
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9 pages, 4005 KiB  
Communication
Development of a Fluorescein-Based Probe with an “Off–On” Mechanism for Selective Detection of Copper (II) Ions and Its Application in Imaging of Living Cells
by Yinjuan Bai, Hongpeng Zhang, Bingqin Yang and Xin Leng
Biosensors 2023, 13(3), 301; https://doi.org/10.3390/bios13030301 - 21 Feb 2023
Cited by 7 | Viewed by 1510
Abstract
Copper is a common metallic element that plays an extremely essential role in the physiological activities of living organisms. The slightest change in copper levels in the human body can trigger various diseases. Therefore, it is important to accurately and efficiently monitor copper [...] Read more.
Copper is a common metallic element that plays an extremely essential role in the physiological activities of living organisms. The slightest change in copper levels in the human body can trigger various diseases. Therefore, it is important to accurately and efficiently monitor copper ion levels in the human body. Recent studies have shown that fluorescent probes have obvious advantages in bioimaging and Cu2+ detection. Therefore, a novel Cu2+ probe (N2) was designed and synthesized from fluorescein, hydrazine hydrate and 5-p-nitrophenylfurfural that is sensitive to and can detect Cu2+ within 100 s. The response mechanism of the N2 probe to Cu2+ was studied by several methods such as Job’s plots and MS analysis, which showed that the Cu2+ and the N2 probe were coordinated in a complexation ratio of 1:1. In addition, compared with other cations investigated in this study, the N2 probe showed excellent selectivity and sensitivity to Cu2+, exhibiting distinct fluorescence absorption at 525 nm. Furthermore, in the equivalent range of 0.1–1.5, there is a good linear relationship between Cu2+ concentration and fluorescence intensity, and the detection limit is 0.10 μM. It is worth mentioning that the reversible reaction between the N2 probe and Cu2+, as well as the good biocompatibility shown by the probe in bioimaging, make it a promising candidate for Cu2+ biosensor applications. Full article
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13 pages, 6541 KiB  
Article
A New Glutathione-Cleavable Theranostic for Photodynamic Therapy Based on Bacteriochlorin e and Styrylnaphthalimide Derivatives
by Marina A. Pavlova, Pavel A. Panchenko, Ekaterina A. Alekhina, Anastasia A. Ignatova, Anna D. Plyutinskaya, Andrey A. Pankratov, Dmitriy A. Pritmov, Mikhail A. Grin, Alexey V. Feofanov and Olga A. Fedorova
Biosensors 2022, 12(12), 1149; https://doi.org/10.3390/bios12121149 - 08 Dec 2022
Cited by 3 | Viewed by 1460
Abstract
Herein, we report a new conjugate BChl–S–S–NI based on the second-generation photosensitizer bacteriochlorin e6 (BChl) and a 4-styrylnaphthalimide fluorophore (NI), which is cleaved into individual functional fragments in the intracellular medium. The chromophores in the conjugate were cross-linked by click chemistry via a [...] Read more.
Herein, we report a new conjugate BChl–S–S–NI based on the second-generation photosensitizer bacteriochlorin e6 (BChl) and a 4-styrylnaphthalimide fluorophore (NI), which is cleaved into individual functional fragments in the intracellular medium. The chromophores in the conjugate were cross-linked by click chemistry via a bis(azidoethyl)disulfide bridge which is reductively cleaved by the intracellular enzyme glutathione (GSH). A photophysical investigation of the conjugate in solution by using optical spectroscopy revealed that the energy transfer process is realized with high efficiency in the conjugated system, leading to the quenching of the emission of the fluorophore fragment. It was shown that the conjugate is cleaved by GSH in solution, which eliminates the possibility of energy transfer and restores the fluorescence of 4-styrylnaphthalimide. The photoinduced activity of the conjugate and its imaging properties were investigated on the mouse soft tissue sarcoma cell line S37. Phototoxicity studies in vitro show that the BChl–S–S–NI conjugate has insignificant dark cytotoxicity in the concentration range from 15 to 20,000 nM. At the same time, upon photoexcitation, it exhibits high photoinduced activity. Full article
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12 pages, 3173 KiB  
Article
Dual Response Site Fluorescent Probe for Highly Sensitive Detection of Cys/Hcy and GSH In Vivo through Two Different Emission Channels
by Huiling Hou, Qi Liu, Xiangbao Liu, Shuang Fu, Hongguang Zhang, Shuang Li, Song Chen and Peng Hou
Biosensors 2022, 12(11), 1056; https://doi.org/10.3390/bios12111056 - 21 Nov 2022
Cited by 6 | Viewed by 1671
Abstract
Much research has demonstrated that metabolic imbalances of biothiols are closely associated with the emergence of different types of disease. In view of the significant effect of biothiols, quantitative evaluation and discrimination of intracellular Cys/Hcy and GSH in complex biological environments is very [...] Read more.
Much research has demonstrated that metabolic imbalances of biothiols are closely associated with the emergence of different types of disease. In view of the significant effect of biothiols, quantitative evaluation and discrimination of intracellular Cys/Hcy and GSH in complex biological environments is very important. In this study, probe CDS-NBD, synthesized by attaching 2,4-dinitrobenzenesulfonate (DNBS, site 1) and nitrobenzoxadiazole (NBD, site 2) as the highly sensitive and selective dual response site for thiols onto the coumarin derivative 7-hydroxycoumarin-4-acetic acid, exhibited large separation of the emission wavelengths, fast response, notable fluorescence enhancement, excellent sensitivity and selectivity to Cys/Hcy and GSH over other biological species. Additionally, CDS-NBD could make a distinction between two different fluorescent signals, GSH (an obvious blue fluorescence) and Cys/Hcy (a mixed blue-green fluorescence). Further study on imaging of Cys/Hcy and GSH in vivo by employing probe CDS-NBD could also be successfully achieved. Full article
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10 pages, 1794 KiB  
Article
Novel Fluorescence Probe toward Cu2+ Based on Fluorescein Derivatives and Its Bioimaging in Cells
by Xin Leng, Du Wang, Zhaoxiang Mi, Yuchen Zhang, Bingqin Yang and Fulin Chen
Biosensors 2022, 12(9), 732; https://doi.org/10.3390/bios12090732 - 06 Sep 2022
Cited by 9 | Viewed by 1535
Abstract
Copper is an important trace element that plays a crucial role in various physiological and biochemical processes in the body. The level of copper content is significantly related to many diseases, so it is very important to establish effective and sensitive methods for [...] Read more.
Copper is an important trace element that plays a crucial role in various physiological and biochemical processes in the body. The level of copper content is significantly related to many diseases, so it is very important to establish effective and sensitive methods for copper detection in vitro and vivo. Copper-selective probes have attracted considerable interest in environmental testing and life-process research, but fewer investigations have focused on the luminescence mechanism and bioimaging for Cu2+ detection. In the current study, a novel fluorescein-based A5 fluorescence probe is synthesized and characterized, and the bioimaging performance of the probe is also tested. We observed that the A5 displayed extraordinary selectivity and sensitivity properties to Cu2+ in contrast to other cations in solution. The reaction between A5 and Cu2+ could accelerate the ring-opening process, resulting in a new band at 525 nm during a larger pH range. A good linearity between the fluorescence intensity and concentrations of Cu2+, ranging from 0.1 to 1.5 equivalent, was observed, and the limit detection of A5 to Cu2+ was 0.11 μM. In addition, the Job’s plot and mass spectrum showed that A5 complexed Cu2+ in a 1:1 manner. The apparent color change in the A5–Cu2+ complex under ultraviolet light at low molar concentrations revealed that A5 is a suitable probe for the detection of Cu2+. The biological test results show that the A5 probe has good biocompatibility and can be used for the cell imaging of Cu2+. Full article
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15 pages, 10660 KiB  
Article
Green, Efficient Detection and Removal of Hg2+ by Water-Soluble Fluorescent Pillar[5]arene Supramolecular Self-Assembly
by Xiaomei Jiang, Lingyun Wang, Xueguang Ran, Hao Tang and Derong Cao
Biosensors 2022, 12(8), 571; https://doi.org/10.3390/bios12080571 - 27 Jul 2022
Cited by 4 | Viewed by 1633
Abstract
Developing a water-soluble supramolecular system for the detection and removal of Hg2+ is extremely needed but remains challenging. Herein, we reported the facile construction of a fluorescent supramolecular system (HG) in 100% water through the self-assembly of carboxylatopillar[5]arene [...] Read more.
Developing a water-soluble supramolecular system for the detection and removal of Hg2+ is extremely needed but remains challenging. Herein, we reported the facile construction of a fluorescent supramolecular system (HG) in 100% water through the self-assembly of carboxylatopillar[5]arene sodium salts (H) and diketopyrrolopyrrole-bridged bis(quaternary ammonium) guest (G) by host–guest interaction. With the addition of Hg2+, the fluorescence of HG could be efficiently quenched. Since Hg2+ showed synergistic interactions (coordination and Hg2+- cavity interactions with G and H, respectively), crosslinked networks of HG@Hg2+ were formed. A sensitive response to Hg2+ with excellent selectivity and a low limit of detection (LOD) of 7.17 × 10−7 M was obtained. Significantly, the quenching fluorescence of HG@Hg2+ can be recovered after a simple treatment with Na2S. The reusability of HG for the detection of Hg2+ ions was retained for four cycles, indicating the HG could be efficiently used in a reversible manner. In addition, the HG could efficiently detect Hg2+ concentration in real samples (tap water and lake water). The developed supramolecular system in 100% water provides great potential in the treatment of Hg2+ detection and removal for environmental sustainability. Full article
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Review

Jump to: Editorial, Research

20 pages, 9399 KiB  
Review
Organic Semiconducting Nanoparticles for Biosensor: A Review
by Zheng Wang, Dongyang Han, Hongzhen Wang, Meng Zheng, Yanyi Xu and Haichang Zhang
Biosensors 2023, 13(4), 494; https://doi.org/10.3390/bios13040494 - 21 Apr 2023
Cited by 2 | Viewed by 2032
Abstract
Highly bio-compatible organic semiconductors are widely used as biosensors, but their long-term stability can be compromised due to photo-degradation and structural instability. To address this issue, scientists have developed organic semiconductor nanoparticles (OSNs) by incorporating organic semiconductors into a stable framework or self-assembled [...] Read more.
Highly bio-compatible organic semiconductors are widely used as biosensors, but their long-term stability can be compromised due to photo-degradation and structural instability. To address this issue, scientists have developed organic semiconductor nanoparticles (OSNs) by incorporating organic semiconductors into a stable framework or self-assembled structure. OSNs have shown excellent performance and can be used as high-resolution biosensors in modern medical and biological research. They have been used for a wide range of applications, such as detecting small biological molecules, nucleic acids, and enzyme levels, as well as vascular imaging, tumor localization, and more. In particular, OSNs can simulate fine particulate matters (PM2.5, indicating particulate matter with an aerodynamic diameter less than or equal to 2.5 μm) and can be used to study the biodistribution, clearance pathways, and health effects of such particles. However, there are still some problems that need to be solved, such as toxicity, metabolic mechanism, and fluorescence intensity. In this review, based on the structure and design strategies of OSNs, we introduce various types of OSNs-based biosensors with functional groups used as biosensors and discuss their applications in both in vitro and in vivo tracking. Finally, we also discuss the design strategies and potential future trends of OSNs-based biosensors. This review provides a theoretical scaffold for the design of high-performance OSNs-based biosensors and highlights important trends and future directions for their development and application. Full article
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17 pages, 4276 KiB  
Review
Conjugated Aggregation-Induced Fluorescent Materials for Biofluorescent Probes: A Review
by Zheng Wang, Ji Ma, Changlin Li and Haichang Zhang
Biosensors 2023, 13(2), 159; https://doi.org/10.3390/bios13020159 - 19 Jan 2023
Cited by 5 | Viewed by 2354
Abstract
The common fluorescent conjugated materials present weak or quenching luminescent phenomena in the solid or aggregate state (ACQ), which limits their applications in medicine and biology. In the last two decades, certain materials, named aggregation-induced emission (AIE) fluorescent materials, have exhibited strong luminescent [...] Read more.
The common fluorescent conjugated materials present weak or quenching luminescent phenomena in the solid or aggregate state (ACQ), which limits their applications in medicine and biology. In the last two decades, certain materials, named aggregation-induced emission (AIE) fluorescent materials, have exhibited strong luminescent properties in the aggregate state, which can overcome the ACQ phenomenon. Due to their intrinsic properties, the AIE materials have been successfully used in biolabeling, where they can not only detect the species of ions and their concentrations in organisms, but can also monitor the organisms’ physiological activity. In addition, these kinds of materials often present non-biological toxicity. Thus, AIE materials have become some of the most popular biofluorescent probe materials and are attracting more and more attention. This field is still in its early infancy, and several open challenges urgently need to be addressed, such as the materials’ biocompatibility, metabolism, and so on. Designing a high-performance AIE material for biofluorescent probes is still challenging. In this review, based on the molecular design concept, various AIE materials with functional groups in the biofluorescent probes are introduced, including tetrastyrene materials, distilbene anthracene materials, triphenylamine materials, and hexaphenylsilole materials. In addition, according to the molecular system design strategy, the donor–acceptor (D-A) system and hydrogen-bonding AIE materials used as biofluorescent probes are reviewed. Finally, the biofluorescent probe design concept and potential evolution trends are discussed. The final goal is to outline a theoretical scaffold for the design of high-performance AIE biofluorescent probes that can at the same time further the development of the applications of AIE-based biofluorescent probes. Full article
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19 pages, 4490 KiB  
Review
Fluorescent Sensing of Glutathione and Related Bio-Applications
by Xiaohuan Sun, Fei Guo, Qianyun Ye, Jinfeng Zhou, Jie Han and Rong Guo
Biosensors 2023, 13(1), 16; https://doi.org/10.3390/bios13010016 - 23 Dec 2022
Cited by 11 | Viewed by 2071
Abstract
Glutathione (GSH), as the most abundant low-molecular-weight biological thiol, plays significant roles in vivo. Abnormal GSH levels have been demonstrated to be related to the dysfunction of specific physiological activities and certain kinds of diseases. Therefore, the sensing of GSH is emerging as [...] Read more.
Glutathione (GSH), as the most abundant low-molecular-weight biological thiol, plays significant roles in vivo. Abnormal GSH levels have been demonstrated to be related to the dysfunction of specific physiological activities and certain kinds of diseases. Therefore, the sensing of GSH is emerging as a critical issue. Cancer, with typical high morbidity and mortality, remains one of the most serious diseases to threaten public health. As it is clear that much more concentrated GSH is present at tumor sites than at normal sites, the in vivo sensing of GSH offers an option for the early diagnosis of cancer. Moreover, by monitoring the amounts of GSH in specific microenvironments, effective diagnosis of ROS levels, neurological diseases, or even stroke has been developed as well. In this review, we focus on the fluorescent methodologies for GSH detection, since they can be conveniently applied in living systems. First, the fluorescent sensing methods are introduced. Then, the principles for fluorescent sensing of GSH are discussed. In addition, the GSH-sensing-related biological applications are reviewed. Finally, the future opportunities in in the areas of fluorescent GSH sensing—in particular, fluorescent GSH-sensing-prompted disease diagnosis—are addressed. Full article
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24 pages, 2069 KiB  
Review
Recent Development of Fluorescent Nanodiamonds for Optical Biosensing and Disease Diagnosis
by Shahzad Ahmad Qureshi, Wesley Wei-Wen Hsiao, Lal Hussain, Haroon Aman, Trong-Nghia Le and Muhammad Rafique
Biosensors 2022, 12(12), 1181; https://doi.org/10.3390/bios12121181 - 19 Dec 2022
Cited by 18 | Viewed by 3448
Abstract
The ability to precisely monitor the intracellular temperature directly contributes to the essential understanding of biological metabolism, intracellular signaling, thermogenesis, and respiration. The intracellular heat generation and its measurement can also assist in the prediction of the pathogenesis of chronic diseases. However, intracellular [...] Read more.
The ability to precisely monitor the intracellular temperature directly contributes to the essential understanding of biological metabolism, intracellular signaling, thermogenesis, and respiration. The intracellular heat generation and its measurement can also assist in the prediction of the pathogenesis of chronic diseases. However, intracellular thermometry without altering the biochemical reactions and cellular membrane damage is challenging, requiring appropriately biocompatible, nontoxic, and efficient biosensors. Bright, photostable, and functionalized fluorescent nanodiamonds (FNDs) have emerged as excellent probes for intracellular thermometry and magnetometry with the spatial resolution on a nanometer scale. The temperature and magnetic field-dependent luminescence of naturally occurring defects in diamonds are key to high-sensitivity biosensing applications. Alterations in the surface chemistry of FNDs and conjugation with polymer, metallic, and magnetic nanoparticles have opened vast possibilities for drug delivery, diagnosis, nanomedicine, and magnetic hyperthermia. This study covers some recently reported research focusing on intracellular thermometry, magnetic sensing, and emerging applications of artificial intelligence (AI) in biomedical imaging. We extend the application of FNDs as biosensors toward disease diagnosis by using intracellular, stationary, and time-dependent information. Furthermore, the potential of machine learning (ML) and AI algorithms for developing biosensors can revolutionize any future outbreak. Full article
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