Biosensors

Editorial

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3 pages, 201 KiB

Open AccessEditorial

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

Cited by 5 | Viewed by 1764

Abstract

Fluorescent materials have great potential for use in biomedical applications due to their ease of functionalization and tunable fluorescence color [...] Full article

(This article belongs to the Special Issue Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging)

Research

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12 pages, 10313 KiB

Open AccessArticle

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 7 | Viewed by 2548

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

(This article belongs to the Special Issue Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging)

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8 pages, 3210 KiB

Open AccessCommunication

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 8 | Viewed by 2955

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

(This article belongs to the Special Issue Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging)

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10 pages, 4890 KiB

Open AccessCommunication

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 - 2 Jun 2023

Cited by 4 | Viewed by 2162

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

(This article belongs to the Special Issue Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging)

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13 pages, 2616 KiB

Open AccessEditor’s ChoiceArticle

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 10 | Viewed by 2441

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

(This article belongs to the Special Issue Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging)

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17 pages, 3144 KiB

Open AccessArticle

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 1634

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

(This article belongs to the Special Issue Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging)

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17 pages, 5038 KiB

Open AccessArticle

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 3 | Viewed by 2573

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

(This article belongs to the Special Issue Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging)

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11 pages, 2294 KiB

Open AccessCommunication

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 6 | Viewed by 2154

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

(This article belongs to the Special Issue Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging)

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9 pages, 4005 KiB

Open AccessCommunication

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 10 | Viewed by 2028

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

(This article belongs to the Special Issue Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging)

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13 pages, 6541 KiB

Open AccessArticle

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 - 8 Dec 2022

Cited by 3 | Viewed by 1930

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

(This article belongs to the Special Issue Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging)

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12 pages, 3173 KiB

Open AccessArticle

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 8 | Viewed by 2165

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

(This article belongs to the Special Issue Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging)

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10 pages, 1794 KiB

Open AccessArticle

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 - 6 Sep 2022

Cited by 15 | Viewed by 2044

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

(This article belongs to the Special Issue Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging)

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15 pages, 10660 KiB

Open AccessArticle

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 2067

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 (H⊃G) 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 (H⊃G) 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 H⊃G could be efficiently quenched. Since Hg²⁺ showed synergistic interactions (coordination and Hg²⁺- cavity interactions with G and H, respectively), crosslinked networks of H⊃G@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 H⊃G@Hg²⁺ can be recovered after a simple treatment with Na₂S. The reusability of H⊃G for the detection of Hg²⁺ ions was retained for four cycles, indicating the H⊃G could be efficiently used in a reversible manner. In addition, the H⊃G 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

(This article belongs to the Special Issue Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging)

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Review

Jump to: Editorial, Research

20 pages, 9399 KiB

Open AccessReview

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 4 | Viewed by 2969

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 (PM_2.5, 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

(This article belongs to the Special Issue Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging)

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17 pages, 4276 KiB

Open AccessEditor’s ChoiceReview

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 10 | Viewed by 3387

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

(This article belongs to the Special Issue Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging)

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19 pages, 4490 KiB

Open AccessReview

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 15 | Viewed by 2847

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

(This article belongs to the Special Issue Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging)

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24 pages, 2069 KiB

Open AccessReview

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 27 | Viewed by 4503

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

(This article belongs to the Special Issue Fluorescent Materials with Excellent Biocompatibility and Their Application in Bio-Sensing, Bio-Imaging)

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