Antibodies are crucial in various biological applications due to their specific binding to target molecules, altering protein function and structure. The advent of single-chain antibodies such as nanobodies has paved the way for broader applicability in both research and therapies due to their small size and efficient tissue penetration. Recently, several approaches have been reported to optically control the antigen-binding affinity of nanobodies. Here, we show an alternative strategy for creating photo-activatable nanobodies. By fusing the photocleavable protein PhoCl with the N-terminus of the nanobody (named optoNb60), we successfully demonstrated light-dependent restoration of the antigen-binding ability and the following modulation of the activity of a target protein, the beta-2 adrenergic receptor. Moreover, the activation of optoNb60 was monitored by the fluorescence changes upon photoconversion. The compatibility of the uncaging design with the previously reported optogenetic molecules using nanobodies will contribute to the further optimization of the response capabilities of existing optogenetic tools, thereby expanding their applicability.
抗体能与目标分子特异性结合，改变蛋白质的功能和结构，因此在各种生物应用中至关重要。单链抗体（如纳米抗体）因其体积小、组织穿透力强，为更广泛地应用于研究和治疗铺平了道路。最近，有几种方法被报道用于光学控制纳米抗体的抗原结合亲和力。在这里，我们展示了另一种制造光活化纳米抗体的策略。通过将可光裂解蛋白 PhoCl 与纳米抗体（命名为 optoNb60）的 N 端融合，我们成功地证明了光依赖性抗原结合能力的恢复，以及随后对靶蛋白--β-2 肾上腺素能受体--活性的调节。此外，我们还通过光电转换时的荧光变化监测了 optoNb60 的活化情况。开笼设计与之前报道的使用纳米抗体的光遗传分子的兼容性将有助于进一步优化现有光遗传工具的反应能力，从而扩大其适用范围。
{"title":"Optical control of nanobody-mediated protein activity modulation with a photocleavable fluorescent protein.","authors":"Mizuki Endo, Saki Tomizawa, Qiaoyue Kuang, Takeaki Ozawa","doi":"10.1039/d4an00433g","DOIUrl":"https://doi.org/10.1039/d4an00433g","url":null,"abstract":"<p><p>Antibodies are crucial in various biological applications due to their specific binding to target molecules, altering protein function and structure. The advent of single-chain antibodies such as nanobodies has paved the way for broader applicability in both research and therapies due to their small size and efficient tissue penetration. Recently, several approaches have been reported to optically control the antigen-binding affinity of nanobodies. Here, we show an alternative strategy for creating photo-activatable nanobodies. By fusing the photocleavable protein PhoCl with the N-terminus of the nanobody (named optoNb60), we successfully demonstrated light-dependent restoration of the antigen-binding ability and the following modulation of the activity of a target protein, the beta-2 adrenergic receptor. Moreover, the activation of optoNb60 was monitored by the fluorescence changes upon photoconversion. The compatibility of the uncaging design with the previously reported optogenetic molecules using nanobodies will contribute to the further optimization of the response capabilities of existing optogenetic tools, thereby expanding their applicability.</p>","PeriodicalId":63,"journal":{"name":"Analyst","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141445592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Carbon dots (CDs), including carbon quantum dots, graphene quantum dots, carbon nanodots, and polymer dots, have gained significant attention due to their unique structural and fluorescence characteristics. This review provides a comprehensive overview of the classification, structural characteristics, and fluorescence properties of CDs, followed by an exploration of various fluorescence sensing mechanisms and their applications in gene detection, nucleolus imaging, and gene delivery. Furthermore, the functionalization of CDs with diverse surface ligand molecules, including dye molecules, nucleic acid probes, and metal derivatives for sensitive nucleic acid detection is systematically examined. Fluorescence imaging of cell nucleolus plays a vital role in examining intracellular processes and dynamics of subcellular structures. By analyzing the mechanism of fluorescence and structure-function relationships inherent in CDs, the nucleolus targeting abilities of CDs in various cell lines have been discussed. Additionally, challenges such as the insufficient organelle specificity of CDs and the inconsistent mechanisms underlying nucleolus targeting have also been highlighted. The unique physical and chemical properties of CDs, particularly their strong affinity toward deoxyribonucleic acid (DNA), have spurred interest in gene delivery applications. The use of nuclear targeting peptides, polymers, and ligands in conjunction with CDs for improved gene delivery applications have been systematically reviewed. Through a comprehensive analysis, the review aims to contribute to a deeper understanding of the potentials and challenges associated with CDs in biomedical applications.
碳点（CD），包括碳量子点、石墨烯量子点、碳纳米点和聚合物点，因其独特的结构和荧光特性而备受关注。这篇综述全面概述了 CD 的分类、结构特征和荧光特性，随后探讨了各种荧光传感机制及其在基因检测、核仁成像和基因递送中的应用。此外，还系统地研究了 CD 与各种表面配体分子（包括染料分子、核酸探针和金属衍生物）的功能化，以实现灵敏的核酸检测。细胞核的荧光成像在研究细胞内过程和亚细胞结构动态方面发挥着重要作用。通过分析 CD 本身的荧光机制和结构功能关系，讨论了 CD 在不同细胞系中的核仁靶向能力。此外，CDs 细胞器特异性不足和核仁靶向机制不一致等挑战也得到了强调。CD具有独特的物理和化学特性，尤其是对脱氧核糖核酸（DNA）具有很强的亲和力，这激发了人们对基因递送应用的兴趣。本文系统地综述了将核靶向肽、聚合物和配体与 CD 结合使用以改进基因递送应用的情况。通过全面分析，该综述旨在帮助人们更深入地了解 CDs 在生物医学应用中的潜力和挑战。
{"title":"Comprehensive Review on Fluorescent Carbon Dots and Their Applications in Nucleic Acid Detection, Nucleolus Targeted Imaging and Gene Delivery","authors":"Selva Sharma Arumugam, Nae Yoon Lee","doi":"10.1039/d4an00630e","DOIUrl":"https://doi.org/10.1039/d4an00630e","url":null,"abstract":"Carbon dots (CDs), including carbon quantum dots, graphene quantum dots, carbon nanodots, and polymer dots, have gained significant attention due to their unique structural and fluorescence characteristics. This review provides a comprehensive overview of the classification, structural characteristics, and fluorescence properties of CDs, followed by an exploration of various fluorescence sensing mechanisms and their applications in gene detection, nucleolus imaging, and gene delivery. Furthermore, the functionalization of CDs with diverse surface ligand molecules, including dye molecules, nucleic acid probes, and metal derivatives for sensitive nucleic acid detection is systematically examined. Fluorescence imaging of cell nucleolus plays a vital role in examining intracellular processes and dynamics of subcellular structures. By analyzing the mechanism of fluorescence and structure-function relationships inherent in CDs, the nucleolus targeting abilities of CDs in various cell lines have been discussed. Additionally, challenges such as the insufficient organelle specificity of CDs and the inconsistent mechanisms underlying nucleolus targeting have also been highlighted. The unique physical and chemical properties of CDs, particularly their strong affinity toward deoxyribonucleic acid (DNA), have spurred interest in gene delivery applications. The use of nuclear targeting peptides, polymers, and ligands in conjunction with CDs for improved gene delivery applications have been systematically reviewed. Through a comprehensive analysis, the review aims to contribute to a deeper understanding of the potentials and challenges associated with CDs in biomedical applications.","PeriodicalId":63,"journal":{"name":"Analyst","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141452921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Axillary malodour is caused by the microbial conversion of human-derived precursors to volatile organic compounds. Thiols strongly contribute to this odour but are hard to detect due to being present in low quantities. Additionally, thiols are highly volatile and small making sampling and analysis difficult including by gas chromatography-mass spectrometry. This makes their detection and quantification extremely difficult. In this study, surface-enhanced Raman scattering (SERS) combined with chemometrics was utilised to simultaneously quantify four malodourous thiols associated with axillary odour both in individual and multiplex solutions. Univariate and multivariate methods of partial least squares regression (PLS-R) were used to calculate the limit of detection (LoD) and results compared. Both methods yielded comparable LoD values, with LoDs using PLS-R ranging from 0.0227 ppm to 0.0153 ppm for the thiols studied. These thiols were then examined and quantified simultaneously in 120 mixtures using PLS-R. The resultant models showed high linearity (Q2 values between 0.9712 and 0.9827 for both PLS-1 and PLS-2) and low values of root mean squared error of predictions (0.0359 ppm and 0.0459 ppm for PLS-1 and PLS-2, respectively). To test this approach further, these models were challenged with 15 new blind test samples collected independently from the initial samples. This test demonstrated that SERS combined with PLS-R could be used to predict the unknown concentrations of these thiols in a mixture. These results display the ability of SERS for the simultaneous multiplex detection and its potential for future development for detecting gaseous thiols produced from skin or body sites.
{"title":"Using surface-enhanced Raman scattering for simultaneous multiplex detection and quantification of thiols associated to axillary malodour","authors":"Amy Colleran, Cássio Lima, Yun Xu, Allen Millichope, Stephanie Murray, Royston Goodacre","doi":"10.1039/d4an00762j","DOIUrl":"https://doi.org/10.1039/d4an00762j","url":null,"abstract":"Axillary malodour is caused by the microbial conversion of human-derived precursors to volatile organic compounds. Thiols strongly contribute to this odour but are hard to detect due to being present in low quantities. Additionally, thiols are highly volatile and small making sampling and analysis difficult including by gas chromatography-mass spectrometry. This makes their detection and quantification extremely difficult. In this study, surface-enhanced Raman scattering (SERS) combined with chemometrics was utilised to simultaneously quantify four malodourous thiols associated with axillary odour both in individual and multiplex solutions. Univariate and multivariate methods of partial least squares regression (PLS-R) were used to calculate the limit of detection (LoD) and results compared. Both methods yielded comparable LoD values, with LoDs using PLS-R ranging from 0.0227 ppm to 0.0153 ppm for the thiols studied. These thiols were then examined and quantified simultaneously in 120 mixtures using PLS-R. The resultant models showed high linearity (Q2 values between 0.9712 and 0.9827 for both PLS-1 and PLS-2) and low values of root mean squared error of predictions (0.0359 ppm and 0.0459 ppm for PLS-1 and PLS-2, respectively). To test this approach further, these models were challenged with 15 new blind test samples collected independently from the initial samples. This test demonstrated that SERS combined with PLS-R could be used to predict the unknown concentrations of these thiols in a mixture. These results display the ability of SERS for the simultaneous multiplex detection and its potential for future development for detecting gaseous thiols produced from skin or body sites.","PeriodicalId":63,"journal":{"name":"Analyst","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141448192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Safety problems caused by organophosphorus pesticide (OPs) residues are constantly occurring, so the establishment of new methods for the degradation and detection of OPs is of huge scientific significance. In the present study, β-sheet peptides and β-hairpin peptides catalyzing hydrolysis of OPs were designed and synthesized. The peptide sequences with the highest hydrolytic activity (EHSGGVTVDPPLTVEHSAG) were screened by investigating the effect of the location of the active sites of the peptide and the peptide’s structure on the degradation of OPs. In addition, the relationship between peptides’ conformation and hydrolytic activity was further analyzed based on density functional theory and the noncovalent interaction of the peptides with OPs and the electrostatic potential on the molecular surface and molecular docking properties were also investigated. It was found that the peptides with approximate active amino acids consisting of the catalytic triad and with the hairpin structure had the enhanced hydrolytic activity toward OPs’ hydrolysis. To develop an electrochemical sensor technique to detect OPs, the conductive MXene (Ti3C2) material was first immobilized with caffeic acid monolayer via enediol-metal complex chemistry and then bound with β-hairpin peptide (EHSGGVTVDPPLTVEHSAG) via carboxy-amine condensation chemistry between the -COOH of caffeic acid and the -NH2 of peptide to prepare MXene-peptide composite. And then the prepared composite was modified on the surface of a glassy carbon electrode to construct an electrochemical sensor for the detection of OPs. And the developed technique can be used to monitor OPs within 15 min with a two orders of linear working range and with a detection limit of 0.15 μM. Meanwhile, the sensor showed good reliability for the detection of OPs in real vegetables.
{"title":"Degradation and detection of organophosphorus pesticides based on peptides and MXene-peptide composite materials","authors":"Qiuying Wang, Ruiqing Jiu, Yunyao Wang, Zongda Li, Jianan Chen, Haochi Liu, Jifeng Liu, Jia Cao","doi":"10.1039/d4an00674g","DOIUrl":"https://doi.org/10.1039/d4an00674g","url":null,"abstract":"Safety problems caused by organophosphorus pesticide (OPs) residues are constantly occurring, so the establishment of new methods for the degradation and detection of OPs is of huge scientific significance. In the present study, β-sheet peptides and β-hairpin peptides catalyzing hydrolysis of OPs were designed and synthesized. The peptide sequences with the highest hydrolytic activity (EHSGGVTVDPPLTVEHSAG) were screened by investigating the effect of the location of the active sites of the peptide and the peptide’s structure on the degradation of OPs. In addition, the relationship between peptides’ conformation and hydrolytic activity was further analyzed based on density functional theory and the noncovalent interaction of the peptides with OPs and the electrostatic potential on the molecular surface and molecular docking properties were also investigated. It was found that the peptides with approximate active amino acids consisting of the catalytic triad and with the hairpin structure had the enhanced hydrolytic activity toward OPs’ hydrolysis. To develop an electrochemical sensor technique to detect OPs, the conductive MXene (Ti3C2) material was first immobilized with caffeic acid monolayer via enediol-metal complex chemistry and then bound with β-hairpin peptide (EHSGGVTVDPPLTVEHSAG) via carboxy-amine condensation chemistry between the -COOH of caffeic acid and the -NH2 of peptide to prepare MXene-peptide composite. And then the prepared composite was modified on the surface of a glassy carbon electrode to construct an electrochemical sensor for the detection of OPs. And the developed technique can be used to monitor OPs within 15 min with a two orders of linear working range and with a detection limit of 0.15 μM. Meanwhile, the sensor showed good reliability for the detection of OPs in real vegetables.","PeriodicalId":63,"journal":{"name":"Analyst","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141430355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chaobin Pang, Heng Xu, Jichao Xu, Lei Zhang, Jinhua Wang, Su Jing
Drug resistance presents a significant obstacle in treating human ovarian cancer. The development of effective methods for detecting drug-resistant cancer cells is pivotal for tailoring personalized therapies and prognostic assessments. In this investigation, we introduce a dual-mode detection technique employing a fluorogenic aptamer probe for the qualification of P-glycoprotein (P-gp) in drug-resistant ovarian cancer cells. The probe, initially in an "off" state due to the proximity of a quencher to the fluorophore, exhibits increased fluorescence intensity upon binding with the target. The fluorescence enhancement shows a linear correlation with both the concentration of P-gp and the presence of P-gp in drug-resistant ovarian cancer cells. This correlation is quantifiable, with detection limits of 1.56 nM and 110 cells mL-1. In an alternate mode, the optimized fluorophores, attached to the aptamer, form larger complexes upon binding to the target protein, which diminishes the rotation speed, thereby augmenting fluorescence polarization. The alteration in fluorescence polarization enables the quantitative analysis of P-gp in the cells, ranging from 100 to 1500 cells per milliliter, with a detection limit of 40 cells mL-1. Gene expression analyses, protein expression studies, and immunofluorescence imaging further validated the reliability of our aptamer-based probe for its specificity towards P-gp in drug-resistant cancer cells. Our findings underscore the dual-mode detection approach promises to enhance the diagnosis and treatment of multidrug-resistant ovarian cancer.
{"title":"Qualifying P-glycoprotein in drug-resistant ovarian cancer cells: a dual-mode aptamer probe approach","authors":"Chaobin Pang, Heng Xu, Jichao Xu, Lei Zhang, Jinhua Wang, Su Jing","doi":"10.1039/d4an00803k","DOIUrl":"https://doi.org/10.1039/d4an00803k","url":null,"abstract":"Drug resistance presents a significant obstacle in treating human ovarian cancer. The development of effective methods for detecting drug-resistant cancer cells is pivotal for tailoring personalized therapies and prognostic assessments. In this investigation, we introduce a dual-mode detection technique employing a fluorogenic aptamer probe for the qualification of P-glycoprotein (P-gp) in drug-resistant ovarian cancer cells. The probe, initially in an \"off\" state due to the proximity of a quencher to the fluorophore, exhibits increased fluorescence intensity upon binding with the target. The fluorescence enhancement shows a linear correlation with both the concentration of P-gp and the presence of P-gp in drug-resistant ovarian cancer cells. This correlation is quantifiable, with detection limits of 1.56 nM and 110 cells mL-1. In an alternate mode, the optimized fluorophores, attached to the aptamer, form larger complexes upon binding to the target protein, which diminishes the rotation speed, thereby augmenting fluorescence polarization. The alteration in fluorescence polarization enables the quantitative analysis of P-gp in the cells, ranging from 100 to 1500 cells per milliliter, with a detection limit of 40 cells mL-1. Gene expression analyses, protein expression studies, and immunofluorescence imaging further validated the reliability of our aptamer-based probe for its specificity towards P-gp in drug-resistant cancer cells. Our findings underscore the dual-mode detection approach promises to enhance the diagnosis and treatment of multidrug-resistant ovarian cancer.","PeriodicalId":63,"journal":{"name":"Analyst","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141430509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Armeen Hussain, Kayla Mancini, Yousef Khatib, Glen D O'Neil
Here, we characterize the photovoltage of n-Si/Au light-addressable electrodes (LAEs) over a range of solution potentials from ca. -1 to +1 V. We find that the n-Si/Au photoelectrodes show photovoltages consistent with a semiconductor/liquid junction in contrast to a buried junction, which opposes our previous understanding of how photovoltage originates in these sensors.
{"title":"Characterizing and understanding the photovoltage in n-Si/Au light-addressable electrochemical sensors.","authors":"Armeen Hussain, Kayla Mancini, Yousef Khatib, Glen D O'Neil","doi":"10.1039/d4an00768a","DOIUrl":"https://doi.org/10.1039/d4an00768a","url":null,"abstract":"<p><p>Here, we characterize the photovoltage of n-Si/Au light-addressable electrodes (LAEs) over a range of solution potentials from <i>ca.</i> -1 to +1 V. We find that the n-Si/Au photoelectrodes show photovoltages consistent with a semiconductor/liquid junction in contrast to a buried junction, which opposes our previous understanding of how photovoltage originates in these sensors.</p>","PeriodicalId":63,"journal":{"name":"Analyst","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141416692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Haiying Cai, Peiting Dong, Xiuping Li, Lulu Wang, Tao Li
It is known that the abnormal expression of specific cellular miRNAs is closely related to cell apoptosis, and so monitoring the level change of these miRNAs is in principle able to evaluate the proceeding of apoptosis stimulated by drugs. Towards this goal, here we construct an ultrasensitive electrochemiluminescence (ECL) nanoplatform via the target miRNA-triggered immobilization of spherical nucleic acid enzymes (SNAzymes) onto tetrahedral DNA nanostructures on the electrode surface, which catalyzes the Luminol-H2O2 reaction to output ECL signal. This enables the sensitive and specific detection of two apoptosis-related miRNAs, miR-21 and miR-133a, with a detection limit of 33 aM. Further, we employed the developed ECL nanoplatform to monitor the levels of these two miRNAs inside cancer cells stimulated by DOX, showing that the level of miR-21 decreases, while that of miR-133a increases in the early apoptotic cells. This difference highlights the distinct roles of two target miRNAs that miR-21 promotes the early apoptosis of cancer cells, whereas miR-133a suppresses it, providing new insight into cell physiological processes.
{"title":"Evaluating Early Apoptosis-Related Cellular MiRNAs with an Ultrasensitive Electrochemiluminescence Nanoplatform","authors":"Haiying Cai, Peiting Dong, Xiuping Li, Lulu Wang, Tao Li","doi":"10.1039/d4an00765d","DOIUrl":"https://doi.org/10.1039/d4an00765d","url":null,"abstract":"It is known that the abnormal expression of specific cellular miRNAs is closely related to cell apoptosis, and so monitoring the level change of these miRNAs is in principle able to evaluate the proceeding of apoptosis stimulated by drugs. Towards this goal, here we construct an ultrasensitive electrochemiluminescence (ECL) nanoplatform via the target miRNA-triggered immobilization of spherical nucleic acid enzymes (SNAzymes) onto tetrahedral DNA nanostructures on the electrode surface, which catalyzes the Luminol-H2O2 reaction to output ECL signal. This enables the sensitive and specific detection of two apoptosis-related miRNAs, miR-21 and miR-133a, with a detection limit of 33 aM. Further, we employed the developed ECL nanoplatform to monitor the levels of these two miRNAs inside cancer cells stimulated by DOX, showing that the level of miR-21 decreases, while that of miR-133a increases in the early apoptotic cells. This difference highlights the distinct roles of two target miRNAs that miR-21 promotes the early apoptosis of cancer cells, whereas miR-133a suppresses it, providing new insight into cell physiological processes.","PeriodicalId":63,"journal":{"name":"Analyst","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141430363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This work presents a novel approach for the electrochemical detection of p-nitrophenol (pNP) focusing on the development of a simple and efficient strategy to overcome pNP adsorption. The proposed method involves the functionalization of a silver (Ag) electrode by an electrografted, thin diazonium film. After characterization by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry, the as-functionalized electrode allowed a wide linear detection range to be established in aqueous solutions, spanning from 1 to 500 µM pNP. This outcome indicates that the diazonium film effectively addresses any issues related to adsorption with good repeatability and reproducibility. Furthermore, the sensor’s analytical performances were evaluated yielding a sensitivity and a limit of detection of 0.3819 µA cm-2 µM-1 and 600 nM, respectively. The sensor was also found to exhibit a good selectivity towards pNP and phenolic compounds and was successfully tested on a real water sample.
{"title":"Diazonium-functionalized Silver Electrode for the Sensitive Amperometric Detection of p-Nitrophenol in Water Over a Wide Range of Concentration","authors":"Christelle VIROLLE, David EVRARD, Olivier REYNES","doi":"10.1039/d4an00696h","DOIUrl":"https://doi.org/10.1039/d4an00696h","url":null,"abstract":"This work presents a novel approach for the electrochemical detection of p-nitrophenol (pNP) focusing on the development of a simple and efficient strategy to overcome pNP adsorption. The proposed method involves the functionalization of a silver (Ag) electrode by an electrografted, thin diazonium film. After characterization by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry, the as-functionalized electrode allowed a wide linear detection range to be established in aqueous solutions, spanning from 1 to 500 µM pNP. This outcome indicates that the diazonium film effectively addresses any issues related to adsorption with good repeatability and reproducibility. Furthermore, the sensor’s analytical performances were evaluated yielding a sensitivity and a limit of detection of 0.3819 µA cm-2 µM-1 and 600 nM, respectively. The sensor was also found to exhibit a good selectivity towards pNP and phenolic compounds and was successfully tested on a real water sample.","PeriodicalId":63,"journal":{"name":"Analyst","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141333628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
William Barros Veloso, Gabriel Negrão Meloni, Iana Vitória Spadini Arantes, Lauro Antonio Pradela Filho, Rodrigo Alejandro Abarza Munoz, Thiago R.L.C. Paixão
3D printing has attracted the interest of researchers due to its creative freedom, low cost, and ease of operation. Because of these features, this technology has produced different types of electroanalytical platforms. Despite their popularity, the thermoplastic composites used for electrode fabrication typically have high electrical resistance, resulting in devices with poor electrochemical performance. Herein, we propose a new strategy to improve the electrochemical performance of 3D-printed electrodes and to gain chemical selectivity towards glucose detection. The approach involves synthesising a nanostructured gold film using an infrared laser source directly on the surface of low-contact resistance 3D-printed electrodes. The laser parameters, such as power, focal distance, and beam scan rate, were carefully optimised for the modification steps. Scanning electronic microscopy and energy-dispersive X-ray spectroscopy confirmed the morphology and composition of the nanostructured gold film. After modification, the resulting electrodes could selectively detect glucose, encouraging their use for sensing applications. When compared with a gold disc electrode, the gold-modified 3D-printed electrode provided a 44-fold current increase for glucose oxidation. As proof of concept, the devices were utilised for the non-enzymatic catalytic determination of glucose in drink samples, demonstrating the gold film's catalytic nature and confirming the analytical applicability with more precise results than commercial glucometers.
3D 打印技术以其自由创意、低成本和易于操作等特点吸引了研究人员的兴趣。由于这些特点，该技术已生产出不同类型的电分析平台。尽管很受欢迎，但用于电极制造的热塑性复合材料通常具有较高的电阻，导致设备的电化学性能较差。在此，我们提出了一种新策略来改善 3D 打印电极的电化学性能，并获得葡萄糖检测的化学选择性。该方法是利用红外激光源直接在低接触电阻 3D 打印电极表面合成纳米结构金膜。激光参数（如功率、焦距和光束扫描速率）在改性步骤中经过了仔细优化。扫描电子显微镜和能量色散 X 射线光谱证实了纳米结构金膜的形态和成分。改性后的电极可以选择性地检测葡萄糖，从而促进了其在传感领域的应用。与金圆盘电极相比，金修饰的 3D 打印电极在葡萄糖氧化过程中的电流增加了 44 倍。作为概念验证，这些装置被用于饮料样品中葡萄糖的非酶催化测定，证明了金膜的催化性质，并证实了其分析适用性，其结果比商用血糖仪更精确。
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Surface enhanced Raman scattering (SERS) provides a label free method of analyzing molecules from diverse and complex signals, potentially with single molecule sensitivity. The chemical specificity inherent in the SERS spectrum can identify molecules; however signal variabilty arising the from diversity of plasmonic environments can limit quantification, particularly at low concentrations. Here we show that digitizing, or counting SERS events, can decrease the limit of detection in flowing solutions enabling quantification of single molecules. By using multivariate curve resolution and establishing a score threshold, each individual spectrum can be classified as containing an event or not. This binary “yes/no” can then be quantified, and a linear region can be established. This method was shown to lower the limit of detection to the lowest physical limit, and lowered the limit of detection by an order of magnitude from the traditional, intensity based LOD calculations.
{"title":"Digital surface enhanced Raman spectroscopy for quantifiable single molecule detection in flow","authors":"Hannah C Schorr, Zachary D Schultz","doi":"10.1039/d4an00801d","DOIUrl":"https://doi.org/10.1039/d4an00801d","url":null,"abstract":"Surface enhanced Raman scattering (SERS) provides a label free method of analyzing molecules from diverse and complex signals, potentially with single molecule sensitivity. The chemical specificity inherent in the SERS spectrum can identify molecules; however signal variabilty arising the from diversity of plasmonic environments can limit quantification, particularly at low concentrations. Here we show that digitizing, or counting SERS events, can decrease the limit of detection in flowing solutions enabling quantification of single molecules. By using multivariate curve resolution and establishing a score threshold, each individual spectrum can be classified as containing an event or not. This binary “yes/no” can then be quantified, and a linear region can be established. This method was shown to lower the limit of detection to the lowest physical limit, and lowered the limit of detection by an order of magnitude from the traditional, intensity based LOD calculations.","PeriodicalId":63,"journal":{"name":"Analyst","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141315548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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