Research

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15 pages, 3329 KiB

Open AccessArticle

Sensitive Electrochemical Detection of Carcinoembryonic Antigen Based on Biofunctionalized Nanochannel Modified Carbonaceous Electrode

by Yucheng Zhou, Hongxin Wang, Fengna Xi and Chao Lu

Molecules 2024, 29(4), 858; https://doi.org/10.3390/molecules29040858 - 15 Feb 2024

Cited by 1 | Viewed by 550

Abstract

The convenient construction of carbon-based electrochemical immunosensors with high performance is highly desirable for the efficient detection of tumor biomarkers. In this work, an electrochemical immunosensor was fabricated by integrating a biofunctionalized mesoporous silica nanochannel film with a carbon-based electrode, which can enable [...] Read more.

The convenient construction of carbon-based electrochemical immunosensors with high performance is highly desirable for the efficient detection of tumor biomarkers. In this work, an electrochemical immunosensor was fabricated by integrating a biofunctionalized mesoporous silica nanochannel film with a carbon-based electrode, which can enable the sensitive determination of carcinoembryonic antigen (CEA) in serum. The commonly used carbonaceous electrode, glassy carbon electrode (GCE), was employed as the supporting electrode and was pre-treated through electrochemical polarization to achieve the stable binding of a vertically ordered mesoporous silica film with amino groups (NH₂-VMSF) without the use of any adhesive layer. To fabricate the immunorecognition interface, antibodies were covalently immobilized after the amino groups on the outer surface of NH₂-VMSF was derivatized to aldehyde groups. The presence of amino sites within the high-density nanochannels of NH₂-VMSF can facilitate the migration of negatively charged redox probes (Fe(CN)₆^3-/4-) to the supporting electrode through electrostatic adsorption, leading to the generation of electrochemical signals. In the presence of CEA, the formation of immunocomplexes on the recognitive interface can reduce the electrochemical signal of Fe(CN)₆^3-/4- on the supporting electrode. Based on this principle, the sensitive electrochemical detection of CEA was achieved. CEA can be determined to range from 0.01 ng mL⁻¹ to 100 ng mL⁻¹ with a limit of detection of 6.3 pg mL⁻¹. The fabricated immunosensor exhibited high selectivity, and the detection of CEA in fetal bovine serum was achieved. Full article

(This article belongs to the Special Issue Advanced Nano-Based Chemsensors and Biosensors for Detective Application)

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12 pages, 3680 KiB

Open AccessArticle

A Photoelectrochemical Sensor for the Detection of Hypochlorous Acid with a Phenothiazine-Based Photosensitizer

by Lijie Luo, Yewen Yang, Shu Chen, Peisheng Zhang and Rongjin Zeng

Molecules 2024, 29(3), 614; https://doi.org/10.3390/molecules29030614 - 27 Jan 2024

Viewed by 674

Abstract

This paper presents the development of a photoelectrochemical sensor for hypochlorous acid (HOCl) detection, employing a phenothiazine-based organic photosensitizer (Dye-PZ). The designed probe, Dye-PZ, follows a D-π-A structure with phenothiazine as the electron-donating group and a cyano-substituted pyridine unit as the electron-accepting group. [...] Read more.

This paper presents the development of a photoelectrochemical sensor for hypochlorous acid (HOCl) detection, employing a phenothiazine-based organic photosensitizer (Dye-PZ). The designed probe, Dye-PZ, follows a D-π-A structure with phenothiazine as the electron-donating group and a cyano-substituted pyridine unit as the electron-accepting group. A specific reaction of the phenothiazine sulfur atom with HOCl enables selective recognition. The covalent immobilization of Dye-PZ onto a titanium dioxide nanorod-coated fluorine-doped tin oxide electrode (FTO/TiO₂) using bromo-silane coupling agent (BrPTMS) resulted in the fabrication of the photoanode FTO/TiO₂/BrPTMS/Dye-PZ. The photoanode exhibited a significant photoresponse under visible-light irradiation, with a subsequent reduction in photocurrent upon reaction with HOCl. The oxidation of the phenothiazine sulfur atom to a sulfoxide diminished the internal charge transfer (ICT) effect. Leveraging this principle, the successful photoelectrochemical sensing of HOCl was achieved. The sensor showed high stability, excellent reproducibility, and selective sensitivity for HOCl detection. Our study provides a novel approach for the development of efficient photoelectrochemical sensors based on organic photosensitizers, with promising applications in water quality monitoring and biosensing. Full article

(This article belongs to the Special Issue Advanced Nano-Based Chemsensors and Biosensors for Detective Application)

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12 pages, 5227 KiB

Open AccessArticle

Ag@AuNP-Functionalized Capillary-Based SERS Sensing Platform for Interference-Free Detection of Glucose in Urine Using SERS Tags with Built-In Nitrile Signal

by Yanmei Si, Hua Wang, Yehao Yan, Bingwen Li, Zeyun Ni and Hongrui Shi

Molecules 2023, 28(24), 7939; https://doi.org/10.3390/molecules28247939 - 05 Dec 2023

Viewed by 936

Abstract

A Ag@AuNP-functionalized capillary-based surface-enhanced Raman scattering (SERS) sensing platform for the interference-free detection of glucose using SERS tags with a built-in nitrile signal has been proposed in this work. Capillary-based SERS capture substrates were prepared by connecting 4-mercaptophenylboronic acid (MBA) to the surface [...] Read more.

A Ag@AuNP-functionalized capillary-based surface-enhanced Raman scattering (SERS) sensing platform for the interference-free detection of glucose using SERS tags with a built-in nitrile signal has been proposed in this work. Capillary-based SERS capture substrates were prepared by connecting 4-mercaptophenylboronic acid (MBA) to the surface of the Ag@AuNP layer anchored on the inner wall of the capillaries. The SERS tags with a built-in interference-free signal could then be fixed onto the Ag@AuNP layer of the capillary-based capture substrate based on the distinguished feature of glucose, which can form a bidentate glucose–boronic complex. Thus, many “hot spots” were formed, which produced an improved SERS signal. The quantitative analysis of glucose levels was realized using the interference-free SERS intensity of nitrile at 2222 cm⁻¹, with a detection limit of about 0.059 mM. Additionally, the capillary-based disposable SERS sensing platform was successfully employed to detect glucose in artificial urine, and the new strategy has great potential to be further applied in the diagnosis and control of diabetes. Full article

(This article belongs to the Special Issue Advanced Nano-Based Chemsensors and Biosensors for Detective Application)

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12 pages, 5211 KiB

Open AccessArticle

Background-Quenched Aggregation-Induced Emission through Electrostatic Interactions for the Detection of Poly(ADP-ribose) Polymerase-1 Activity

by Fengli Gao, Ruimin Zhao, Liping Huang and Xinyao Yi

Molecules 2023, 28(12), 4759; https://doi.org/10.3390/molecules28124759 - 14 Jun 2023

Cited by 1 | Viewed by 943

Abstract

Poly(ADP-ribose) polymerase-1 (PARP1) is a potential biomarker and therapeutic target for cancers that can catalyze the poly-ADP-ribosylation of nicotinamide adenine dinucleotide (NAD⁺) onto the acceptor proteins to form long poly(ADP-ribose) (PAR) polymers. Through integration with aggregation-induced emission (AIE), a background-quenched strategy [...] Read more.

Poly(ADP-ribose) polymerase-1 (PARP1) is a potential biomarker and therapeutic target for cancers that can catalyze the poly-ADP-ribosylation of nicotinamide adenine dinucleotide (NAD⁺) onto the acceptor proteins to form long poly(ADP-ribose) (PAR) polymers. Through integration with aggregation-induced emission (AIE), a background-quenched strategy for the detection of PARP1 activity was designed. In the absence of PARP1, the background signal caused by the electrostatic interactions between quencher-labeled PARP1-specitic DNA and tetraphenylethene-substituted pyridinium salt (TPE-Py, a positively charged AIE fluorogen) was low due to the fluorescence resonance energy transfer effect. After poly-ADP-ribosylation, the TPE-Py fluorogens were recruited by the negatively charged PAR polymers to form larger aggregates through electrostatic interactions, thus enhancing the emission. The detection limit of this method for PARP1 detection was found to be 0.006 U with a linear range of 0.01~2 U. The strategy was used to evaluate the inhibition efficiency of inhibitors and the activity of PARP1 in breast cancer cells with satisfactory results, thus showing great potential for clinical diagnostic and therapeutic monitoring. Full article

(This article belongs to the Special Issue Advanced Nano-Based Chemsensors and Biosensors for Detective Application)

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14 pages, 3557 KiB

Open AccessArticle

Preparation of Molecularly Imprinted Cysteine Modified Zinc Sulfide Quantum Dots Based Sensor for Rapid Detection of Dopamine Hydrochloride

by Xin Zhang, Meng Wang, Yating Zhang, Pan Zhao, Jiamei Cai, Yunjian Yao and Jiarong Liang

Molecules 2023, 28(9), 3646; https://doi.org/10.3390/molecules28093646 - 22 Apr 2023

Cited by 2 | Viewed by 1504

Abstract

By combining surface molecular imprinting technology with cysteine-modified ZnS quantum dots, an elegant, molecularly imprinted cysteine-modified Mn²⁺: ZnS QDs (MIP@ZnS QDs) based fluorescence sensor was successfully developed. The constructed fluorescence sensor is based on a molecularly imprinted polymer (MIP) coated on [...] Read more.

By combining surface molecular imprinting technology with cysteine-modified ZnS quantum dots, an elegant, molecularly imprinted cysteine-modified Mn²⁺: ZnS QDs (MIP@ZnS QDs) based fluorescence sensor was successfully developed. The constructed fluorescence sensor is based on a molecularly imprinted polymer (MIP) coated on the surface cysteine-modified ZnS quantum dots and used for rapid fluorescence detection of dopamine hydrochloride. The MIP@ZnS quantum dots possess the advantages of rapid response, high sensitivity, and selectivity for the detection of dopamine hydrochloride molecules. Experimental results show that the adsorption equilibrium time of MIP@ZnS QDs for dopamine hydrochloride molecules is 12 min, and it can selectively capture and bind dopamine in the sample with an imprinting factor of 29.5. The fluorescence quenching of MIP@ZnS QDs has a good linear (R² = 0.9936) with the concentration of dopamine hydrochloride ranged from 0.01 to 1.0 μM, and the limit of detection is 3.6 nM. In addition, The MIP@ZnS QDs demonstrate good recyclability and stability and are successfully employed for detection of dopamine hydrochloride in urine samples with recoveries was 95.2% to 103.8%. The proposed MIP@ZnS QDs based fluorescent sensor provides a promising approach for food safety detection and drug analysis. Full article

(This article belongs to the Special Issue Advanced Nano-Based Chemsensors and Biosensors for Detective Application)

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10 pages, 1835 KiB

Open AccessCommunication

Switch-on Fluorescence Analysis of Protease Activity with the Assistance of a Nickel Ion-Nitrilotriacetic Acid-Conjugated Magnetic Nanoparticle

by Xiaohua Ma, Yingxin Lv, Panpan Liu, Yuanqiang Hao and Ning Xia

Molecules 2023, 28(8), 3426; https://doi.org/10.3390/molecules28083426 - 13 Apr 2023

Cited by 1 | Viewed by 1197

Abstract

Heterogeneous protease biosensors show high sensitivity and selectivity but usually require the immobilization of peptide substrates on a solid interface. Such methods exhibit the disadvantages of complex immobilization steps and low enzymatic efficiency induced by steric hindrance. In this work, we proposed an [...] Read more.

Heterogeneous protease biosensors show high sensitivity and selectivity but usually require the immobilization of peptide substrates on a solid interface. Such methods exhibit the disadvantages of complex immobilization steps and low enzymatic efficiency induced by steric hindrance. In this work, we proposed an immobilization-free strategy for protease detection with high simplicity, sensitivity and selectivity. Specifically, a single-labeled peptide with oligohistidine-tag (His-tag) was designed as the protease substrate, which can be captured by a nickel ion-nitrilotriacetic acid (Ni-NTA)-conjugated magnetic nanoparticle (MNP) through the coordination interaction between His-tag and Ni-NTA. When the peptide was digested by protease in a homogeneous solution, the signal-labeled segment was released from the substrate. The unreacted peptide substrates could be removed by Ni-NTA-MNP, and the released segments remained in solution to emit strong fluorescence. The method was used to determine protease of caspase-3 with a low detection limit (4 pg/mL). By changing the peptide sequence and signal reporters, the proposal could be used to develop novel homogeneous biosensors for the detection of other proteases. Full article

(This article belongs to the Special Issue Advanced Nano-Based Chemsensors and Biosensors for Detective Application)

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12 pages, 2342 KiB

Open AccessArticle

A Turn-On and Colorimetric Probe Based on Isophorone Skeleton for Detecting Nerve Agent Mimic Diethyl Chlorophosphite

by Xue-Shuang Yu, Mao-Mei Zhu, Rui Zuo, Yu Peng and Ya-Wen Wang

Molecules 2023, 28(7), 3237; https://doi.org/10.3390/molecules28073237 - 05 Apr 2023

Cited by 2 | Viewed by 1403

Abstract

A new turn-on probe (SWJT-20) based on isophorone fluorophore for the detection of nerve agent mimic diethyl chlorophosphite (DCP) was designed and synthesized. SWJT-20 could rapidly respond to DCP within 2 s using UV-Vis or fluorescent spectra, accompanied by a significant [...] Read more.

A new turn-on probe (SWJT-20) based on isophorone fluorophore for the detection of nerve agent mimic diethyl chlorophosphite (DCP) was designed and synthesized. SWJT-20 could rapidly respond to DCP within 2 s using UV-Vis or fluorescent spectra, accompanied by a significant change in the solution color under visible light or UV light, which could be observed by the naked eyes. The detection limit of SWJT-20 to DCP was as low as 8.3 nM, which is lower than those of most reported fluorescent probes for DCP detection. Additionally, SWJT-20 could quantitatively measure DCP using ratio changes in A₄₂₇/A₆₄₅ in absorption spectra. Furthermore, facile paper as sensors with the visualization of colorimetric/fluorometric responses based on SWJT-20 has been fabricated. Notably, this probe could detect DCP vapor through gas diffusion experiments. Full article

(This article belongs to the Special Issue Advanced Nano-Based Chemsensors and Biosensors for Detective Application)

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Review

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36 pages, 13607 KiB

Open AccessReview

Overview on the Development of Alkaline-Phosphatase-Linked Optical Immunoassays

by Lin Liu, Yong Chang, Jiaxin Lou, Shuo Zhang and Xinyao Yi

Molecules 2023, 28(18), 6565; https://doi.org/10.3390/molecules28186565 - 11 Sep 2023

Cited by 1 | Viewed by 1675

Abstract

The drive to achieve ultrasensitive target detection with exceptional efficiency and accuracy requires the advancement of immunoassays. Optical immunoassays have demonstrated significant potential in clinical diagnosis, food safety, environmental protection, and other fields. Through the innovative and feasible combination of enzyme catalysis and [...] Read more.

The drive to achieve ultrasensitive target detection with exceptional efficiency and accuracy requires the advancement of immunoassays. Optical immunoassays have demonstrated significant potential in clinical diagnosis, food safety, environmental protection, and other fields. Through the innovative and feasible combination of enzyme catalysis and optical immunoassays, notable progress has been made in enhancing analytical performances. Among the kinds of reporter enzymes, alkaline phosphatase (ALP) stands out due to its high catalytic activity, elevated turnover number, and broad substrate specificity, rendering it an excellent candidate for the development of various immunoassays. This review provides a systematic evaluation of the advancements in optical immunoassays by employing ALP as the signal label, encompassing fluorescence, colorimetry, chemiluminescence, and surface-enhanced Raman scattering. Particular emphasis is placed on the fundamental signal amplification strategies employed in ALP-linked immunoassays. Furthermore, this work briefly discusses the proposed solutions and challenges that need to be addressed to further enhance the performances of ALP-linked immunoassays. Full article

(This article belongs to the Special Issue Advanced Nano-Based Chemsensors and Biosensors for Detective Application)

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26 pages, 9900 KiB

Open AccessReview

Biosensors with Metal Ion–Phosphate Chelation Interaction for Molecular Recognition

by Xiaohua Ma, Yuanqiang Hao, Xiaoxiao Dong and Ning Xia

Molecules 2023, 28(11), 4394; https://doi.org/10.3390/molecules28114394 - 28 May 2023

Cited by 6 | Viewed by 1474

Abstract

Biosensors show promising prospects in the assays of various targets due to their advantages of high sensitivity, good selectivity and rapid response. Molecular recognition is a key event of biosensors, which usually involves the interaction of antigen–antibody, aptamer–target, lectin–sugar, boronic acid–diol, metal chelation [...] Read more.

Biosensors show promising prospects in the assays of various targets due to their advantages of high sensitivity, good selectivity and rapid response. Molecular recognition is a key event of biosensors, which usually involves the interaction of antigen–antibody, aptamer–target, lectin–sugar, boronic acid–diol, metal chelation and DNA hybridization. Metal ions or complexes can specifically recognize phosphate groups in peptides or proteins, obviating the use of biorecognition elements. In this review, we summarized the design and applications of biosensors with metal ion–phosphate chelation interaction for molecular recognition. The sensing techniques include electrochemistry, fluorescence, colorimetry and so on. Full article

(This article belongs to the Special Issue Advanced Nano-Based Chemsensors and Biosensors for Detective Application)

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30 pages, 13366 KiB

Open AccessReview

Organic Fluorescent Probes for Monitoring Micro-Environments in Living Cells and Tissues

by Rui Yang, Tao Zhu, Jingyang Xu, Yuang Zhao, Yawei Kuang, Mengni Sun, Yuqi Chen, Wei He, Zixing Wang, Tingwang Jiang, Huiguo Zhang and Mengmeng Wei

Molecules 2023, 28(8), 3455; https://doi.org/10.3390/molecules28083455 - 14 Apr 2023

Cited by 5 | Viewed by 2435

Abstract

As a vital parameter in living cells and tissues, the micro-environment is crucial for the living organisms. Significantly, organelles require proper micro-environment to achieve normal physiological processes, and the micro-environment in organelles can reflect the state of organelles in living cells. Moreover, some [...] Read more.

As a vital parameter in living cells and tissues, the micro-environment is crucial for the living organisms. Significantly, organelles require proper micro-environment to achieve normal physiological processes, and the micro-environment in organelles can reflect the state of organelles in living cells. Moreover, some abnormal micro-environments in organelles are closely related to organelle dysfunction and disease development. So, visualizing and monitoring the variation of micro-environments in organelles is helpful for physiologists and pathologists to study the mechanisms of the relative diseases. Recently, a large variety of fluorescent probes was developed to study the micro-environments in living cells and tissues. However, the systematic and comprehensive reviews on the organelle micro-environment in living cells and tissues have rarely been published, which may hinder the research progress in the field of organic fluorescent probes. In this review, we will summarize the organic fluorescent probes for monitoring the microenvironment, such as viscosity, pH values, polarity, and temperature. Further, diverse organelles (mitochondria, lysosome, endoplasmic reticulum, cell membrane) about microenvironments will be displayed. In this process, the fluorescent probes about the “off-on” and ratiometric category (the diverse fluorescence emission) will be discussed. Moreover, the molecular designing, chemical synthesis, fluorescent mechanism, and the bio-applications of these organic fluorescent probes in cells and tissues will also be discussed. Significantly, the merits and defects of current microenvironment-sensitive probes are outlined and discussed, and the development tendency and challenges for this kind of probe are presented. In brief, this review mainly summarizes some typical examples and highlights the progress of organic fluorescent probes for monitoring micro-environments in living cells and tissues in recent research. We anticipate that this review will deepen the understanding of microenvironment in cells and tissues and facilitate the studies and development of physiology and pathology. Full article

(This article belongs to the Special Issue Advanced Nano-Based Chemsensors and Biosensors for Detective Application)

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