Introducing oxygen vacancy into semiconducting metal oxides (SMOs) is a strategic approach to promote their gas sensing performances. In this paper, the WO3-x thin films were meticulously deposited onto an anodic aluminum oxide (AAO) substrate, and the oxygen vacancies concentrations of WO3-x thin films were changed by adjusting the ratio of flux of Ar to O2 in magnetron sputtering process. Sequentially, a layer of palladium (Pd) was deposited on the WO3-x/AAO films, creating a nano-mesh structured hydrogen sensor with Pd as the catalytic element. The resulted amorphous WO3-x samples with varying concentration of oxygen vacancies were thoroughly analyzed using XPS and ESR, which confirmed that the oxygen vacancies concentration escalated with an increase in the ratio of flux of Ar to O2. The hydrogen sensitivity of prepared Pd/WO3-x/AAO sensors were examined. Our findings revealed an enhancement in hydrogen sensitivity for the sensors with an optimal concentration of oxygen vacancies. However, an excess of these vacancies was found to deteriorate their hydrogen sensing performance. Notably, the optimized Pd/WO3-x/AAO sensor exhibited a marked response even at a hydrogen concentration as low as 100 ppb, demonstrating its high sensitivity and selectivity towards hydrogen detection.
{"title":"Introducing oxygen vacancies into WO3 thin film for improving hydrogen sensing performance of Pd/WO3-x/AAO sensors","authors":"Yu Zhang, Chen Hang, Hongchuan Jiang, Xiaohui Zhao, Xinwu Deng, Liufang Wang, Fengxiang Ma, Zhengjie Xu","doi":"10.1016/j.snb.2024.136843","DOIUrl":"https://doi.org/10.1016/j.snb.2024.136843","url":null,"abstract":"Introducing oxygen vacancy into semiconducting metal oxides (SMOs) is a strategic approach to promote their gas sensing performances. In this paper, the WO<sub>3-x</sub> thin films were meticulously deposited onto an anodic aluminum oxide (AAO) substrate, and the oxygen vacancies concentrations of WO<sub>3-x</sub> thin films were changed by adjusting the ratio of flux of Ar to O<sub>2</sub> in magnetron sputtering process. Sequentially, a layer of palladium (Pd) was deposited on the WO<sub>3-x</sub>/AAO films, creating a nano-mesh structured hydrogen sensor with Pd as the catalytic element. The resulted amorphous WO<sub>3-x</sub> samples with varying concentration of oxygen vacancies were thoroughly analyzed using XPS and ESR, which confirmed that the oxygen vacancies concentration escalated with an increase in the ratio of flux of Ar to O<sub>2</sub>. The hydrogen sensitivity of prepared Pd/WO<sub>3-x</sub>/AAO sensors were examined. Our findings revealed an enhancement in hydrogen sensitivity for the sensors with an optimal concentration of oxygen vacancies. However, an excess of these vacancies was found to deteriorate their hydrogen sensing performance. Notably, the optimized Pd/WO<sub>3-x</sub>/AAO sensor exhibited a marked response even at a hydrogen concentration as low as 100 ppb, demonstrating its high sensitivity and selectivity towards hydrogen detection.","PeriodicalId":425,"journal":{"name":"Sensors and Actuators B: Chemical","volume":null,"pages":null},"PeriodicalIF":8.4,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142488687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper reports an optical fiber toluene sensor based on whispering gallery mode (WGM) microbottle resonator. The sensor includes a single-mode fiber (SMF)- no-core fiber (NCF)- SMF offset structure, which can be used as not only a coupler to couple light into the microbottle but also a multimode interferometer. The microbottle is formed by self-assembly of polydimethylsiloxane (PDMS) polymer doped with metal-organic framework (MOF) under the action of surface tension and gravity. The high specific surface area, suitable pore size, nitrogen-containing functional groups of MOF-Fe-PD and nonpolar groups on PDMS impart the high sensitivity and specific response of the sensor to toluene. When toluene is captured by the MOF and PDMS, the refractive index and volume of the cavity change, which affects the mode shift of WGM. According to test results, WGM of the sensor shows a linear sensitivity of 12.44 pm/ppm with toluene concentration between 0 ppm and 337 ppm at room temperature, but it is affected by temperature crosstalk. While multimode interference dip is only sensitive to temperature, which can compensate for the mode shift of WGM caused by temperature change. Repeatability experiments show that the response and recovery time of the sensor are less than 70 s. The method provides a toluene sensor with high selectivity, stable performance and simple preparation, which has potential environmental benefits and good industrial application prospects.
{"title":"Highly-selective and temperature-compensated toluene sensor based on MOF-actuated optical WGM microresonator","authors":"Mingyue Wang, Yingxuan Liu, Yutong Sun, Qi Liu, Ya-nan Zhang","doi":"10.1016/j.snb.2024.136838","DOIUrl":"https://doi.org/10.1016/j.snb.2024.136838","url":null,"abstract":"This paper reports an optical fiber toluene sensor based on whispering gallery mode (WGM) microbottle resonator. The sensor includes a single-mode fiber (SMF)- no-core fiber (NCF)- SMF offset structure, which can be used as not only a coupler to couple light into the microbottle but also a multimode interferometer. The microbottle is formed by self-assembly of polydimethylsiloxane (PDMS) polymer doped with metal-organic framework (MOF) under the action of surface tension and gravity. The high specific surface area, suitable pore size, nitrogen-containing functional groups of MOF-Fe-PD and nonpolar groups on PDMS impart the high sensitivity and specific response of the sensor to toluene. When toluene is captured by the MOF and PDMS, the refractive index and volume of the cavity change, which affects the mode shift of WGM. According to test results, WGM of the sensor shows a linear sensitivity of 12.44<!-- --> <!-- -->pm/ppm with toluene concentration between 0 ppm and 337 ppm at room temperature, but it is affected by temperature crosstalk. While multimode interference dip is only sensitive to temperature, which can compensate for the mode shift of WGM caused by temperature change. Repeatability experiments show that the response and recovery time of the sensor are less than 70<!-- --> <!-- -->s. The method provides a toluene sensor with high selectivity, stable performance and simple preparation, which has potential environmental benefits and good industrial application prospects.","PeriodicalId":425,"journal":{"name":"Sensors and Actuators B: Chemical","volume":null,"pages":null},"PeriodicalIF":8.4,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142488070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-23DOI: 10.1016/j.snb.2024.136795
This study demonstrates a low crosstalk temperature-compensated fiber-based urea sensor based on the hybridization of surface plasmon resonance (SPR) and Mach-Zehnder interferometer (MZI). In this sensing structure, an inscribed waveguide and a semi-open cavity are processed by a femtosecond laser in an optical fiber to excite an SPR signal sensitive to refractive index (RI) and an MZI signal highly sensitive to temperature. Based on the temperature detected by the MZI, the influence of temperature on the SPR signal’s RI detection can be calculated and compensated for using a sensitivity matrix. Based on this precise RI detection of the SPR signal, we have achieved selective urea detection by bio-functionalizing the sensor surface using the urease self-assembly method. The sensitivity and limit of detection for urea are 7.98 (nm/mmol/L) and 0.13 mmol/L, respectively, which are better than those in previous studies. Compared to previous temperature compensation studies, this SPR + MZI sensing method using femtosecond laser processing significantly improves the temperature sensitivity of the MZI signal, which reduces crosstalk and ensures a sufficient working range for the SPR signal. Therefore, this sensor is crucial for advancing high-precision temperature compensation detection, high-sensitivity biological detection, and the future application of the femtosecond laser technology.
{"title":"Temperature-compensated optical fiber sensor for urea detection based on the femtosecond laser-inscribed process","authors":"","doi":"10.1016/j.snb.2024.136795","DOIUrl":"10.1016/j.snb.2024.136795","url":null,"abstract":"<div><div>This study demonstrates a low crosstalk temperature-compensated fiber-based urea sensor based on the hybridization of surface plasmon resonance (SPR) and Mach-Zehnder interferometer (MZI). In this sensing structure, an inscribed waveguide and a semi-open cavity are processed by a femtosecond laser in an optical fiber to excite an SPR signal sensitive to refractive index (RI) and an MZI signal highly sensitive to temperature. Based on the temperature detected by the MZI, the influence of temperature on the SPR signal’s RI detection can be calculated and compensated for using a sensitivity matrix. Based on this precise RI detection of the SPR signal, we have achieved selective urea detection by bio-functionalizing the sensor surface using the urease self-assembly method. The sensitivity and limit of detection for urea are 7.98 (nm/mmol/L) and 0.13 mmol/L, respectively, which are better than those in previous studies. Compared to previous temperature compensation studies, this SPR + MZI sensing method using femtosecond laser processing significantly improves the temperature sensitivity of the MZI signal, which reduces crosstalk and ensures a sufficient working range for the SPR signal. Therefore, this sensor is crucial for advancing high-precision temperature compensation detection, high-sensitivity biological detection, and the future application of the femtosecond laser technology.</div></div>","PeriodicalId":425,"journal":{"name":"Sensors and Actuators B: Chemical","volume":null,"pages":null},"PeriodicalIF":8.0,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142486972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-23DOI: 10.1016/j.snb.2024.136822
Surface Enhanced Raman Scattering (SERS) has the advantages of non-destructive detection and high sensitivity, however, low hotspots utilisation and inhomogeneous distribution limit its application. In response to the problem of underutilization of hotspots in most SERS substrates, a crosslinking of chitosan with dialdehyde chitosan aerogels loaded with Ag NPs (CDSA) as SERS substrates with chitosan (CS) as the main body and dialdehyde chitosan (DACS) as the reducing and cross-linking agent were prepared. Unlike other 3D structures such as hydrogels, CDSA can capture probe molecules in a much shorter period of time and enhance SERS signals by collapse. The SERS performance of CDSA was evaluated by rhodamine 6 G (R6G) and methylene blue (MB), indicating that the CDSA substrate has good stability (90 days), repeatability (RSD=4.15 %) and reproducibility (RSD=4.86 %). The enhancement factors (EFs) was 1.3×108 for R6G and 9.2×107 for MB. Both gas sample and liquid sample were detected to evaluate the performances of CDSA in practical application. 4-Aminothiophenol (4-ATP) was utilized to test the efficacy of CDSA on gas-phase to-be-tested substances and the limit of detection (LOD) was 0.59 mg/L. The tests performed on sildenafil (SD) in real samples showed recoveries ranging from 97.5 % to 103.4 % with a LOD of 0.055 mg/L. It was indicated that the CDSA substrate could serves as a satisfactory SERS sensor for sensitive and rapid detection for both gas phase and liquid samples.
{"title":"Plasmonic chitosan cross-linked dialdehyde chitosan aerogels as 3D surface-enhanced Raman scattering substrates for sensitive and reliable detection","authors":"","doi":"10.1016/j.snb.2024.136822","DOIUrl":"10.1016/j.snb.2024.136822","url":null,"abstract":"<div><div>Surface Enhanced Raman Scattering (SERS) has the advantages of non-destructive detection and high sensitivity, however, low hotspots utilisation and inhomogeneous distribution limit its application. In response to the problem of underutilization of hotspots in most SERS substrates, a crosslinking of chitosan with dialdehyde chitosan aerogels loaded with Ag NPs (CDSA) as SERS substrates with chitosan (CS) as the main body and dialdehyde chitosan (DACS) as the reducing and cross-linking agent were prepared. Unlike other 3D structures such as hydrogels, CDSA can capture probe molecules in a much shorter period of time and enhance SERS signals by collapse. The SERS performance of CDSA was evaluated by rhodamine 6 G (R6G) and methylene blue (MB), indicating that the CDSA substrate has good stability (90 days), repeatability (RSD=4.15 %) and reproducibility (RSD=4.86 %). The enhancement factors (EFs) was 1.3×10<sup>8</sup> for R6G and 9.2×10<sup>7</sup> for MB. Both gas sample and liquid sample were detected to evaluate the performances of CDSA in practical application. 4-Aminothiophenol (4-ATP) was utilized to test the efficacy of CDSA on gas-phase to-be-tested substances and the limit of detection (LOD) was 0.59 mg/L. The tests performed on sildenafil (SD) in real samples showed recoveries ranging from 97.5 % to 103.4 % with a LOD of 0.055 mg/L. It was indicated that the CDSA substrate could serves as a satisfactory SERS sensor for sensitive and rapid detection for both gas phase and liquid samples.</div></div>","PeriodicalId":425,"journal":{"name":"Sensors and Actuators B: Chemical","volume":null,"pages":null},"PeriodicalIF":8.0,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142487023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-23DOI: 10.1016/j.snb.2024.136836
Despite growing interest in matrix metalloproteinases (MMPs) as promising therapeutic targets for cancer treatments, cellular trafficking and release of MMPs remain underexplored. To evaluate to what content the MMP secretion is associated with extracellular vesicles (EVs), in this study, we report a droplet microfluidic assay for simultaneous dynamic monitoring of the MMP and EV secretion at the single-cell level. Microdroplets containing single cells were generated in a flow-focusing microchannel and then guided to a microcolumn array for on-chip patterning, incubation and time-lapse microscopy. Utilizing a green fluorescent substrate for MMP activity and a red fluorescent protein reporter for EVs, temporal secretion dynamics of MMPs and EVs from individual cells were recorded respectively. With this dual-reporter system, a strong correlation between MMP and EV secretion was revealed. We further demonstrated that promotion or inhibition of EV release by altering intracellular calcium levels would induce a rise or fall in single-cell MMP secretion, which was masked by population-based experiments. More importantly, the activated release of this EV subpopulation (exosomes) also resulted in a higher correlation coefficient between MMP and EV secretion, and vice versa. Therefore, compared to other EV subpopulations, exosomes should be more closely connected with MMP secretion, and thus may represent a potential target for combination therapy. When in contrast with bulk experiments, single-cell analysis of the secretion correlation between MMPs and EVs not only reveals extensive cellular heterogeneity, but also exhibits a higher resolution.
尽管人们对基质金属蛋白酶（MMPs）作为癌症治疗靶点的兴趣与日俱增，但对MMPs的细胞运输和释放仍缺乏深入研究。为了评估 MMP 的分泌与细胞外囊泡 (EV) 的关联程度，我们在本研究中报告了一种液滴微流控检测方法，用于在单细胞水平同时动态监测 MMP 和 EV 的分泌。含有单细胞的微滴在流动聚焦微通道中产生，然后被引导至微柱阵列，进行片上图案化、孵育和延时显微镜观察。利用绿色荧光底物检测 MMP 活性和红色荧光蛋白报告物检测 EVs，分别记录单个细胞的 MMP 和 EVs 的时间分泌动态。通过这种双报告系统，我们发现了 MMP 和 EV 分泌之间的密切联系。我们进一步证明，通过改变细胞内钙水平来促进或抑制 EV 的释放，会引起单细胞 MMP 分泌的上升或下降，而基于群体的实验却掩盖了这一现象。更重要的是，这种EV亚群（外泌体）的激活释放也导致MMP与EV分泌之间的相关系数更高，反之亦然。因此，与其他 EV 亚群相比，外泌体应该与 MMP 的分泌有更密切的联系，从而可能成为联合治疗的潜在靶点。与大块实验相比，单细胞分析 MMP 与 EV 之间的分泌相关性不仅能揭示广泛的细胞异质性，而且分辨率更高。
{"title":"Secretion correlation between matrix metalloproteinases and extracellular vesicles revealed by synchronized dynamic monitoring of single cells on a microfluidic chip","authors":"","doi":"10.1016/j.snb.2024.136836","DOIUrl":"10.1016/j.snb.2024.136836","url":null,"abstract":"<div><div>Despite growing interest in matrix metalloproteinases (MMPs) as promising therapeutic targets for cancer treatments, cellular trafficking and release of MMPs remain underexplored. To evaluate to what content the MMP secretion is associated with extracellular vesicles (EVs), in this study, we report a droplet microfluidic assay for simultaneous dynamic monitoring of the MMP and EV secretion at the single-cell level. Microdroplets containing single cells were generated in a flow-focusing microchannel and then guided to a microcolumn array for on-chip patterning, incubation and time-lapse microscopy. Utilizing a green fluorescent substrate for MMP activity and a red fluorescent protein reporter for EVs, temporal secretion dynamics of MMPs and EVs from individual cells were recorded respectively. With this dual-reporter system, a strong correlation between MMP and EV secretion was revealed. We further demonstrated that promotion or inhibition of EV release by altering intracellular calcium levels would induce a rise or fall in single-cell MMP secretion, which was masked by population-based experiments. More importantly, the activated release of this EV subpopulation (exosomes) also resulted in a higher correlation coefficient between MMP and EV secretion, and vice versa. Therefore, compared to other EV subpopulations, exosomes should be more closely connected with MMP secretion, and thus may represent a potential target for combination therapy. When in contrast with bulk experiments, single-cell analysis of the secretion correlation between MMPs and EVs not only reveals extensive cellular heterogeneity, but also exhibits a higher resolution.</div></div>","PeriodicalId":425,"journal":{"name":"Sensors and Actuators B: Chemical","volume":null,"pages":null},"PeriodicalIF":8.0,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142487307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-22DOI: 10.1016/j.snb.2024.136832
Single nucleotide polymorphism (SNP) discrimination plays an important role in precision medicine by providing insights into an individual’s genetic information. The low abundance of the mutant target and the minimal impact caused by SNP on the whole nucleic acid sequence remain a challenge during discrimination. Herein, a cascade strand displacement reaction mediated label-free Cas12a sensing platform is established for SNP analysis. Split G-quadruplex (G4) motif is recruited as label-free signal output for Cas12a sensing system, and hence overcomes relying of fluorescence labeled substrates like conventional method. The established platform exhibits excellent single base difference discrimination ability attributing to the cascade strand displacement process, during which, single-base mismatch will affect the strand-exchange rate significantly. The limit of detection reaches 1 copy / test after integration with isothermal preamplification. The proposed method can discriminate as low as 0.1 % single base variation and perform robustly in biological matrixes. Human buccal swab samples are successfully genotyped with high accuracy.
单核苷酸多态性（SNP）判别可深入了解个体的遗传信息，在精准医疗中发挥着重要作用。突变靶点的丰度较低，且 SNP 对整个核酸序列的影响极小，这仍然是判别过程中的一个挑战。在此，我们建立了一个级联链置换反应介导的无标记 Cas12a 感测平台，用于 SNP 分析。分裂的 G-四联体（G4）图案作为 Cas12a 感测系统的无标记信号输出，从而克服了传统方法对荧光标记底物的依赖。由于在级联链置换过程中，单碱基错配会显著影响链交换速率，因此所建立的平台具有出色的单碱基差异分辨能力。经等温前置扩增整合后，检测限可达 1 拷贝/次。所提出的方法可分辨低至 0.1% 的单碱基变异，在生物基质中表现稳定。人类颊拭子样本的基因分型成功且准确度高。
{"title":"Single nucleotide polymorphism discrimination and genotyping based on cascade strand displacement reaction mediated label-free Cas12a system","authors":"","doi":"10.1016/j.snb.2024.136832","DOIUrl":"10.1016/j.snb.2024.136832","url":null,"abstract":"<div><div>Single nucleotide polymorphism (SNP) discrimination plays an important role in precision medicine by providing insights into an individual’s genetic information. The low abundance of the mutant target and the minimal impact caused by SNP on the whole nucleic acid sequence remain a challenge during discrimination. Herein, a cascade strand displacement reaction mediated label-free Cas12a sensing platform is established for SNP analysis. Split G-quadruplex (G4) motif is recruited as label-free signal output for Cas12a sensing system, and hence overcomes relying of fluorescence labeled substrates like conventional method. The established platform exhibits excellent single base difference discrimination ability attributing to the cascade strand displacement process, during which, single-base mismatch will affect the strand-exchange rate significantly. The limit of detection reaches 1 copy / test after integration with isothermal preamplification. The proposed method can discriminate as low as 0.1 % single base variation and perform robustly in biological matrixes. Human buccal swab samples are successfully genotyped with high accuracy.</div></div>","PeriodicalId":425,"journal":{"name":"Sensors and Actuators B: Chemical","volume":null,"pages":null},"PeriodicalIF":8.0,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142486971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-22DOI: 10.1016/j.snb.2024.136831
Point-of-care (PoC) devices offer the possibility of fast and easy to use testing platforms. Self-driven capillary devices are particularly interesting because they can function without external pumps. Microfluidic devices often rely on polydimethylsiloxane (PDMS) prototyping; however, for self-driven microfluidics, its hydrophobic nature makes its use challenging. Bulk modification of PDMS through copolymers with hydrophilic moieties could be a practical solution because the copolymer is added prior to PDMS baking in a single-step process. In this work, a PDMS bulk modification with dimethylsiloxane-(60–70 % ethylene oxide) block copolymer was used to render PDMS hydrophilic. The addition of 1 % (w/w) copolymer resulted in a hydrophilic PDMS which was then used to fabricate the capillary devices. The microfluidic design included a serpentine channel with reagent entry points connected to a capillary pump and was closed by a membrane layer with conical shaped reservoirs. The reservoirs were designed to allow the sequential entry of the solutions and the device sealing and robustness were improved through PMMA frames with integrated magnets. A proof-of-concept was performed with food colouring demonstrating the capability of the device to flow the solutions sequentially. Finally, an immunoassay to detect the presence of Infliximab, a therapeutic antibody for chronic inflammatory diseases, was used to demonstrate the functionality of the capillary device. The versatility of the device was also shown by performing a fluorescent indirect immunoassay and a colorimetric indirect-ELISA for the detection of Infliximab with both approaches detecting Infliximab in the clinical range of interest (between 3 and 7 μg/mL).
{"title":"Microfluidic capillary platform with hydrophilic PDMS for point-of-care immunoassays","authors":"","doi":"10.1016/j.snb.2024.136831","DOIUrl":"10.1016/j.snb.2024.136831","url":null,"abstract":"<div><div>Point-of-care (PoC) devices offer the possibility of fast and easy to use testing platforms. Self-driven capillary devices are particularly interesting because they can function without external pumps. Microfluidic devices often rely on polydimethylsiloxane (PDMS) prototyping; however, for self-driven microfluidics, its hydrophobic nature makes its use challenging. Bulk modification of PDMS through copolymers with hydrophilic moieties could be a practical solution because the copolymer is added prior to PDMS baking in a single-step process. In this work, a PDMS bulk modification with dimethylsiloxane-(60–70 % ethylene oxide) block copolymer was used to render PDMS hydrophilic. The addition of 1 % (w/w) copolymer resulted in a hydrophilic PDMS which was then used to fabricate the capillary devices. The microfluidic design included a serpentine channel with reagent entry points connected to a capillary pump and was closed by a membrane layer with conical shaped reservoirs. The reservoirs were designed to allow the sequential entry of the solutions and the device sealing and robustness were improved through PMMA frames with integrated magnets. A proof-of-concept was performed with food colouring demonstrating the capability of the device to flow the solutions sequentially. Finally, an immunoassay to detect the presence of Infliximab, a therapeutic antibody for chronic inflammatory diseases, was used to demonstrate the functionality of the capillary device. The versatility of the device was also shown by performing a fluorescent indirect immunoassay and a colorimetric indirect-ELISA for the detection of Infliximab with both approaches detecting Infliximab in the clinical range of interest (between 3 and 7 μg/mL).</div></div>","PeriodicalId":425,"journal":{"name":"Sensors and Actuators B: Chemical","volume":null,"pages":null},"PeriodicalIF":8.0,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142486970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-22DOI: 10.1016/j.snb.2024.136777
Here, we report a liquid crystal (LC) double-emulsion based system for organophosphorus (OPs) sensing by controllable release of guest aqueous droplets (GADs) cargo. First, double liquid crystal emulsion, water in liquid crystal in water (W/LC/W), with size between 4∼ 20 μm was prepared with GADs loaded at the center of liquid crystal droplet (LCD) through elasticity trap. The LCDs were monodispersed and response sensitively to amphiphilic surfactant with opposite charge. With the capability of ejecting GADs with human chorionic gonadotropin (hCG) as cargo located in LCD to continuous aqueous phase, responsive vehicles are obtained and applied in the repurposing of commercial pregnancy test strip (PTS). With hydrophobic alkyl chain and hydrophilic head, myristoylcholine (Myr) is a good amphiphilic surfactant to trigger the release of hCG, and substrate for the enzymatic hydrolysis of acetylcholine esterase (AChE). Provided with the inhibition effect of OPs to the hydrolysis ability of AChE, OPs correlate positively with the concentration of Myr, thus correlate well with the release of hCG in W/LC/W emulsion. Thus, OPs residue in river or food is readily visualized using commercial PTS.
{"title":"Responsive release of guest aqueous droplet in liquid crystal droplet assists the detection of organophosphorus using commercial pregnancy test strip","authors":"","doi":"10.1016/j.snb.2024.136777","DOIUrl":"10.1016/j.snb.2024.136777","url":null,"abstract":"<div><div>Here, we report a liquid crystal (LC) double-emulsion based system for organophosphorus (OPs) sensing by controllable release of guest aqueous droplets (GADs) cargo. First, double liquid crystal emulsion, water in liquid crystal in water (W/LC/W), with size between 4∼ 20 μm was prepared with GADs loaded at the center of liquid crystal droplet (LCD) through elasticity trap. The LCDs were monodispersed and response sensitively to amphiphilic surfactant with opposite charge. With the capability of ejecting GADs with human chorionic gonadotropin (hCG) as cargo located in LCD to continuous aqueous phase, responsive vehicles are obtained and applied in the repurposing of commercial pregnancy test strip (PTS). With hydrophobic alkyl chain and hydrophilic head, myristoylcholine (Myr) is a good amphiphilic surfactant to trigger the release of hCG, and substrate for the enzymatic hydrolysis of acetylcholine esterase (AChE). Provided with the inhibition effect of OPs to the hydrolysis ability of AChE, OPs correlate positively with the concentration of Myr, thus correlate well with the release of hCG in W/LC/W emulsion. Thus, OPs residue in river or food is readily visualized using commercial PTS.</div></div>","PeriodicalId":425,"journal":{"name":"Sensors and Actuators B: Chemical","volume":null,"pages":null},"PeriodicalIF":8.0,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142486753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-22DOI: 10.1016/j.snb.2024.136821
The presence of excessive residues of organophosphorus (OPs) and carbamate (CPs) pesticides in food and the environment poses a significant threat to human health and ecological sustainability. Herein, we reported a dual-readout, portable, and highly sensitive photoelectric analyzer (DPHP-analyzer) to achieve rapid and accurate monitoring of OPs and CPs. The dual signal strategy is mainly achieved by controlling the activity of acetylcholinesterase (AChE) in the presence of OPs to catalyze acetylthiocholine (ATCh) and generate thiocholine (TCh), which specifically induced the conversion of colorless Ellman's reagent (DTNB) into yellow 5-thio-2-nitrobenzoic acid (TNB). Simultaneously, the utilization of positively charged TNB as an absorber can induce a dynamic fluorescence quenching effect based on energy transfer mechanism. Fully cooperating with the above mechanism, a CD like, disposable array-based chip manufactured by 3D printing (CD-AN-chip) was designed and integrated to deliver reagents. By use of this dual-output strategy, the analyzer and chip can provide good sensitivity and selectivity for the monitoring of diazinon and carbendazim (case analysis) with a LOD 0.38 ng/mL for carbendazim. And the reproducibility, stability and practicability analysis of real sample have been thoroughly validated simultaneously. Importantly, with the features of fluorescence fingerprint map, the detector could be employed for the distinction of various analytes and further be used for monitoring the nutritional environment within residential and public settings.
有机磷（OPs）和氨基甲酸酯（CPs）农药在食品和环境中的过量残留对人类健康和生态可持续性构成了严重威胁。在此，我们报告了一种双读数、便携式、高灵敏度的光电分析仪（DPHP-analyzer），以实现对 OPs 和 CPs 的快速准确监测。双信号策略主要是通过控制乙酰胆碱酯酶（AChE）在 OPs 存在下催化乙酰硫代胆碱（ATCh）并生成硫代胆碱（TCh）的活性，从而特异性地诱导无色的埃尔曼试剂（DTNB）转化为黄色的 5-硫代-2-硝基苯甲酸（TNB）。同时，利用带正电荷的 TNB 作为吸收剂，还能诱导基于能量转移机制的动态荧光淬灭效应。在上述机制的充分配合下，我们设计并集成了一种通过 3D 打印技术制造的类似 CD 的一次性阵列芯片（CD-AN-chip）来传输试剂。利用这种双输出策略，分析仪和芯片可以为监测地嗪农和多菌灵（病例分析）提供良好的灵敏度和选择性，多菌灵的检测限为 0.38 ng/mL。同时，真实样品分析的重现性、稳定性和实用性也得到了充分验证。重要的是，该检测器具有荧光指纹图谱的特点，可用于区分各种分析物，并可进一步用于监测住宅和公共场所的营养环境。
{"title":"A novel portable in situ analyzer for highly sensitive monitoring of organophosphorus and carbamate pesticides in food and environment","authors":"","doi":"10.1016/j.snb.2024.136821","DOIUrl":"10.1016/j.snb.2024.136821","url":null,"abstract":"<div><div>The presence of excessive residues of organophosphorus (OPs) and carbamate (CPs) pesticides in food and the environment poses a significant threat to human health and ecological sustainability. Herein, we reported a dual-readout, portable, and highly sensitive photoelectric analyzer (DPHP-analyzer) to achieve rapid and accurate monitoring of OPs and CPs. The dual signal strategy is mainly achieved by controlling the activity of acetylcholinesterase (AChE) in the presence of OPs to catalyze acetylthiocholine (ATCh) and generate thiocholine (TCh), which specifically induced the conversion of colorless Ellman's reagent (DTNB) into yellow 5-thio-2-nitrobenzoic acid (TNB). Simultaneously, the utilization of positively charged TNB as an absorber can induce a dynamic fluorescence quenching effect based on energy transfer mechanism. Fully cooperating with the above mechanism, a CD like, disposable array-based chip manufactured by 3D printing (CD-AN-chip) was designed and integrated to deliver reagents. By use of this dual-output strategy, the analyzer and chip can provide good sensitivity and selectivity for the monitoring of diazinon and carbendazim (case analysis) with a LOD 0.38 ng/mL for carbendazim. And the reproducibility, stability and practicability analysis of real sample have been thoroughly validated simultaneously. Importantly, with the features of fluorescence fingerprint map, the detector could be employed for the distinction of various analytes and further be used for monitoring the nutritional environment within residential and public settings.</div></div>","PeriodicalId":425,"journal":{"name":"Sensors and Actuators B: Chemical","volume":null,"pages":null},"PeriodicalIF":8.0,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142487047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-22DOI: 10.1016/j.snb.2024.136779
Rana M. Abdelghani, Walid El-Shafai, Iman Morsi, Taha E. Taha, Abd El-Hady B. Kashyout
This article presents a novel technique for wireless hydrothermally improved gas sensor devices enhanced by molecular imprinting technique (MIT) for hematite nanomaterials with the existence of acetone using different ratios (10%, 15%, and 25%) as well as doping with palladium/ silver to detect the imprinted gas. α-Fe2O3 are characterized utilizing field emission scanning electron microscope (FESEM), photoluminescence, Fourier transforms infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photo-spectroscopy (XPS), and High-Resolution Transmission Electron Microscopy (HRTEM), Thermogravimetric Analysis (TGA) and utilizes Brunauer-Emmett-Teller (BET) to ascertain their shape, optical properties, and values for surface area and thermal characteristics, respectively. Depending on the preparation conditions, non-regular cubes and rods have typical particle sizes ranging from 25 to 120 nm, acetone imprinted and doped with palladium sample (Ap) offers smaller particles than acetone imprinted sample (A15) making adsorption easier. Where XRD showed all diffraction peaks for α-Fe2O3 as well as XPS authorized the oxidation state, also FTIR showed the characteristic peaks of the stretching mode Fe-O which indicates the formation of α-Fe2O3. Lower defects for (Ap) as it has the highest intensity of 176.15 a.u. in the photoluminescent spectrum, for TGA analysis results explain that pure sample has more thermal stability and lower weight loss. Six hematite films are fabricated using the spin coating technique where acetone molecules are presented during the synthesis process of the nanomaterials to imprint their shapes on the surface of hematite. By measuring the response of the gas sensors and their electrical properties, the I-V curve for Ap showed a rectifying behavior and its shunt resistance (Rsh) is higher than series resistance (Rs) which ensures a high response of (115%). To develop a wireless gas sensor COMSOL Multiphysics software 5.3(a) software is used for the simulation of three devices model by depositing a layer by specified dimensions of hematites (A15, As, and Ap) with their different electrical conductivities on the surface of rectangular patch antenna by showing geometry, the microstrip patch antenna bandwidth, resonant frequency, scattering parameters, and radiation patterns in the E-plane and 3-D far-field pattern and directivity is calculated also, Sp gives improved reflection coefficient, gain quality factor and directivity due to its high electrical conductivity.
{"title":"Electrical Properties of Acetone Imprinted Hematite Nanomaterials Doped with Pd & Ag for Gas Sensing and Simulation of their Wireless Devices","authors":"Rana M. Abdelghani, Walid El-Shafai, Iman Morsi, Taha E. Taha, Abd El-Hady B. Kashyout","doi":"10.1016/j.snb.2024.136779","DOIUrl":"https://doi.org/10.1016/j.snb.2024.136779","url":null,"abstract":"This article presents a novel technique for wireless hydrothermally improved gas sensor devices enhanced by molecular imprinting technique (MIT) for hematite nanomaterials with the existence of acetone using different ratios (10%, 15%, and 25%) as well as doping with palladium/ silver to detect the imprinted gas. α-Fe<sub>2</sub>O<sub>3</sub> are characterized utilizing field emission scanning electron microscope (FESEM), photoluminescence, Fourier transforms infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photo-spectroscopy (XPS), and High-Resolution Transmission Electron Microscopy (HRTEM), Thermogravimetric Analysis (TGA) and utilizes Brunauer-Emmett-Teller (BET) to ascertain their shape, optical properties, and values for surface area and thermal characteristics, respectively. Depending on the preparation conditions, non-regular cubes and rods have typical particle sizes ranging from 25 to 120<!-- --> <!-- -->nm, acetone imprinted and doped with palladium sample (Ap) offers smaller particles than acetone imprinted sample (A15) making adsorption easier. Where XRD showed all diffraction peaks for α-Fe<sub>2</sub>O<sub>3</sub> as well as XPS authorized the oxidation state, also FTIR showed the characteristic peaks of the stretching mode Fe-O which indicates the formation of α-Fe<sub>2</sub>O<sub>3</sub>. Lower defects for (Ap) as it has the highest intensity of 176.15 a.u. in the photoluminescent spectrum, for TGA analysis results explain that pure sample has more thermal stability and lower weight loss. Six hematite films are fabricated using the spin coating technique where acetone molecules are presented during the synthesis process of the nanomaterials to imprint their shapes on the surface of hematite. By measuring the response of the gas sensors and their electrical properties, the I-V curve for Ap showed a rectifying behavior and its shunt resistance (Rsh) is higher than series resistance (Rs) which ensures a high response of (115%). To develop a wireless gas sensor COMSOL Multiphysics software 5.3(a) software is used for the simulation of three devices model by depositing a layer by specified dimensions of hematites (A15, As, and Ap) with their different electrical conductivities on the surface of rectangular patch antenna by showing geometry, the microstrip patch antenna bandwidth, resonant frequency, scattering parameters, and radiation patterns in the E-plane and 3-D far-field pattern and directivity is calculated also, Sp gives improved reflection coefficient, gain quality factor and directivity due to its high electrical conductivity.","PeriodicalId":425,"journal":{"name":"Sensors and Actuators B: Chemical","volume":null,"pages":null},"PeriodicalIF":8.4,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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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