bluuebunny/crossref_metadata_2025_split huggingface dataset:
Supercritical Fluids Synthesis of Catalyst Nanoparticles- Decorated Nanocarbon for Low Concentration Formaldehyde Sensing
Authors: Yang Cheng-Kang , Wang Shih-Han , Wen Meng-Jie , Liao Jin-Yi 
Published: May 2020

The formaldehyde (HCHO) is one of a major pollutants in indoor air and it is harmful to healthy even exposed in low concentration. It was regulated that the HCHO concentration should beyond 0.08 ppm[1]. The conventional methods to analyses formaldehyde are GC, HPLC and so on, but those methods are not user friendly. We aimed to develop an electrochemical formaldehyde sensor which is highly sensitive, quick response, cost effective and user friendly. In the previous study, platinum electrocatalyst has wildly applied for the catalytic oxidation of HCHO [2]. Furthermore, some other catalysts such as palladium and copper oxide were used as oxidation catalysts. In this study, the no surface tension property of supercritical fluids were exploited to decorate nanocatalyst onto nanocarbons uniformly. The surface morphology and chemical structure of the materials were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectrometer (FTIR), respectively. The bimetallic electrocatalyst decorated nanocarbon exhibited highly catalytic properties, and the oxidation potential could be less than 0.2 V vs. Ag/AgCl. The sensor showed a wide sensing range from 0-100 ppm and the lower detection limit was 1 ppb. All sensing properties of this HCHO sensor, including sensitivity, stability and repeatability were examined carefully. The selectivity to the potential interferences and the temperature effect were accessed. The experimental results demonstrate high feasibility of this nanocarbon-based HCHO sensor for the indoor air quality monitoring.
References
[1] Environmental Protection Administration Executive Yuan, ROC (2012)
[2] Nie, L., Yu, J., Jaroniec, M., & Tao, F. F. (2016). CATAL SCI TECHNOL, 6(11), 3649–3669. doi:10.1039/c6cy00062b
A Long-Range and Self-Powered Intelligent Food Monitoring System Based on Far-Field Energy Harvesting and Pressure Measurement
Authors: Do Huu-Dung , Chung Wan-Young 
Published: May 2020

Introduction

Radiofrequency (RF) energy harvesting has recently become a promising solution to power wireless sensors networks. As this emerging technology allows low-power sensors and systems to be charged wirelessly, it is advantageous in various applications with low cost and fewer requirements for periodical maintenance [1]. On the other hand, food quality is one of the most concerned problems of our society, foodborne illnesses caused by eating spoilt food has been a serious threat to human health. Therefore, development of a low cost, rapid and sensitive monitoring system is essential to ensure food safety and security. However, conventional food monitoring methods, which are usually based on measuring gas concentration show some drawbacks in terms of power consumption, cost, and reliability [2].
In this study, we developed a high-efficient battery-less system that can be used for food monitoring based on the far-field RF energy harvesting technique.

Methods

Our proposed system consists of an RF energy harvester and a sensing circuit. The RF energy harvester can harvest energy from radio waves at an ultra-high frequency (UHF) of 915 MHz to supply the power for the operation of all tag components. To improve the received power and enhance the distance of power transfer, a Yagi type structure antenna with three elements (driver, director, and reflector) was implemented to achieve a high gain and fit into a compact footprint [3]. Besides, to overcome the disadvantages of conventional food monitoring methods, our study focuses on measuring the increase in air pressure inside the food package caused by gas emission during storage. To confirm the effectiveness of the proposed system, we performed experiments on different sorts of food such as chicken, pork and fish.

Results and Conclusions

As a result, the sensor module is designed using a high accuracy pressure sensor and other ultra-low-power components, allowed it to consume low average power of only 1mW. The designed Yagi antenna has a high gain of 5.23dBi in the direction of the maximum radiation and voltage standing wave ratio (VSWR) better than 1.3 in approximately 60Mhz band (890-950Mhz). Finally, the increase in air pressure during food spoilage was used to categorize food freshness, demonstrating the feasibility of our proposed system.

References

[1] T. Soyata, L. Copeland and W. Heinzelman, "RF Energy Harvesting for Embedded Systems: A Survey of Tradeoffs and Methodology," IEEE Circ. Syst. Mag., vol. 16, no. 1, pp. 22-57, Firstquarter 2016
[2] Chung, W. Y., Le, G. T., Tran, T. V., & Nguyen, N. H. (2017). Novel proximal fish freshness monitoring using batteryless smart sensor tag. Sensors and Actuators B: Chemical, 248, 910-916.
[3] S. Keyrouz, G. Perotto, H. J. Visser and A. G. Tijhuis, Novel broadband yagi-uda antenna for ambient energy harvesting, in IEEE 42nd European Microwave Conf. (EuMC), pp. 518-521, 2012
Biofilm Formation on Two Layer CVD Graphene and Its Change of Capacitance
Authors: Kanematsu Hideyuki , Nakagawa Ryoichi , Saito Kai , Miura Hidekazu , Ishihara Masatou , Ban Masato , Hirai Nobumitsu , Kogo Takeshi , Ogawa Akiko , Barry Dana M. 
Published: May 2020

Biofilms formed on materials have brought about many industrial problems so far. Chronic diseases, the deterioration of hygiene conditions etc. could be mentioned for example. We have confirmed that graphene is easy to form biofilms on it in various ways. Therefore, we expect and predict it could be applied to a practical sensor for biofilm detections. In our precious studies, we produced mono layer graphene on glass specimens and confirmed that it was highly sensitive to biofilm formation in a flow type laboratory biofilm reactor. However, monolayer graphene is generally still lacking in uniformity and the non-coating area is often observed. Therefore, we investigated the sensitivity of two layer CVD graphene to biofilm formation and the possibility to biofilm sensor.
In this study, we focused on the change of capacitance with biofilm formation on the graphene coating. The graphene coating specimens on copper and PET substrates were set to laboratory biofilm reactors and we formed biofilms on the specimens artificially. After the formation of biofilms, the specimens were checked by Raman spectroscopy and also observed by an optical microscopy. And the specimens' capacitances were measured, using a specially devised jig connecting to a LCR meter. The frequencies were changed from 700 to 2000Hz and the capacitances were measured.
As a result, biofilm formed specimens showed small peaks at some characteristics frequencies, while specimens without biofilms showed no peaks at all. Therefore, we presumed that dielectric polarization-relaxation and the loss would occur due to the existence of External Polymeric Substances (EPS) derived from biofilms. We discussed the application possibility of this phenomenon to biofilm sensing.
Reagent-Free Detection of Lead Carbonate Using Stripping Voltammetry
Authors: Huseinov Artur , Alvarez Noe 
Published: May 2020

Nowadays lead pipes are still present in many houses and could be a potential source of this metal in drinking water. Modern polyvinyl chloride pipes also contain compounds of lead, that can be leached from them, causing an increase of Pb concentration in drinking water. That is why regular and simple testing of tap water is necessary to avoid lead poisoning. Voltammetric sensors, due to their high sensitivity, simplicity and low cost, are very good for the detection of lead ions. In tap water, except of free ions, lead may present in various particulate forms (i.e. oxides, hydroxide, insoluble salts, etc.) that cannot be detected directly using electrochemical techniques.
A user-friendly sensor should exclude any sample preparation; however, this step is necessary to bring all the species to the ionic form. It has been reported the possibility of electrochemical pH reduction of water. Oxidation of water occurs easily on most inert electrodes (Pt, Au, etc.), producing hydrogen ions. Generated H+ can chemically interact with some lead species, revealing free lead ions.
The proposed method employs electrochemical generation of hydrogen ions, combined with stripping square wave voltammetry for quantification of lead species in particulate form, using lead carbonate as a model compound. The signal obtained using this method is linearly proportional to the amount of solid PbCO3 added to the solution in the range of 50-250 μg/l.
Electrochemical Imaging of Biomarkers for Oral Cancer Staging
Authors: Lin Yen Tzu , Lin Tzu En 
Published: May 2020

Each year, approximately 450,000 new cases are reported with oral or oropharyngeal cancer worldwide. Despite their high incidence, oral cancers are often neglected at the first stage, resulting in cancer metastasis with high mortality rate, especially for men. Conventional methods for diagnosis of oral cancer rely on the visual inspection and biopsy. However, it may lead to misdiagnosis or delayed diagnosis because of insufficient information. Therefore, it is important to develop a novel tool for the detection of oral cancer at an initial stage itself.
Electrochemical screening methods have shown to be very promising for the rapid, sensitive, and cost-effective detection of oral cancer biomarkers.1 To enhance the resolution of the electrochemical imaging, we employ the concept of image fusion, with the image obtained by scanning electrochemical microscopy (SECM) and optical microscopy. Through the prediction of the presence of biomarkers in tissue area, the fused image can provide a more accurate description of the biomarker distribution of the oral cancer slices. For the purpose of investigating the distribution of IL-6 protein, a biomarker of oral cancer, in different cancer stages, we use SECM to image tissue sections and fused it with H&E stain images obtained by optical microscope. SECM is a scanning probe technique that is composed of three electrode system and soft probe can scan closely over a sample surface. The primary antibody and secondary antibody labeled with horse radish peroxidase (HRP) were applied to reveal the locations of IL-6 on the samples. Then, the cancer sections were immersed in electrolytes containing FcMeOH and H2O2. The FcMeOH+ ions were generated from the catalytic reaction of HRP, and hence, the Faradaic current signals from the reduction of FcMeOH+ can be recorded through the scanning of SECM probe. Due to the fusion of SECM with H&E stain, IL-6 distribution patterns in cancers with different stages can be analyzed precisely. We discovered that in stage III of oral cancer, the IL-6 expression level is the highest as compared to the normal tissue and cancer tissue at earlier stages.

1. T.-E. Lin, Y.-J. Lu, C.-L. Sun, H. Pick, J. P. Chen, A. Lesch, H. H. Girault, Angew. Chem. Int. Ed.
2017, 56, 16498-16
2. T.-E. Lin, C.-L. Chen, Y.-C. Huang, H.-H. Chung, C.-W. Lin, K.-C. Chen, Y.-J. Peng, S.-T. Ding, M.-Y. Wang, T.-L. Shen, C.-C. Hsu Anal. Chim. Acta.
2019.
A Multimodal Electronic Nose Based on High-Density Flexible Sensor Array of Carbon Nanotubes and Photoactive Macromolecules Hybrid Nanostructures
Authors: Huu Tran Thien-Toan , Park Hyusim , To Dung , Gangadhara Karthik , Brady Jacob , Hart Joseph , Jung Sungyong , Myung Nosang Vincent 
Published: May 2020

We report a multimodal electronic nose system based on photoactive carbonaceous hybrid nanomaterials for the detection and quantification of gaseous odors. The e-nose system comprises a high-density flexible sensor array, colorimetric and electrical measurement electronics, data acquisition software, and data analysis algorithms. The e-nose system combines the unique advantages of electrical, chemical, and physical properties of single-walled carbon nanotubes (SWNTs) with optical and chemical properties of various classes of organic macrocyclic compounds, such as pyrenes, porphyrins, and phthalocyanines, for multimodal gas sensing. Photoactive macromolecules such as metalloporphyrins and metallophthalocyanines have been previously developed into colorimetric sensors to various gas analytes. Their intrinsically low electrical conductivity prevents direct application of porphyrins and phthalocyanines in chemiresistive sensors. However, when used as a secondary sensing material via functionalization onto SWNTs, which intrinsically lacks chemical selectivity, these macromolecules confer their chemical selectivity and optical properties to the intrinsically semiconducting SWNT channel. This hybrid nanostructure allows both chemiresistive sensing and colorimetric sensing modalities. Another beneficial property of this hybrid nanostructure is the optoelectronic tunability of the nanomaterial to allow for direct modulation of chemical and electrical behaviors leading to tunable gas sensing capability.
Using the high-density array containing 118 individually addressable sensors, over 60 different secondary sensing materials (functionalized onto SWNTs) were investigated, which include chemical derivatives of pyrenes, porphyrins, and phthalocyanines, which have a large variety of side-groups, and metal centers. Additionally, by integrating a large variety of secondary sensing materials into each sensing element of the 118-sensor array, we take advantage of the different chemical and electrical characteristics of each macromolecules which allow for different affinities to specific VOC species to enhance overall selectivity of the e-nose system. The functionality of the multimodal e-nose system was demonstrated to distinguish and quantify various volatile organic compounds (VOCs).
Manipulating Microvolumes of Fluids in Different Paths By Magnetohydrodynamics
Authors: Fritsch Ingrid , Nicholson Aaron , Khan Foysal Z , Stewart Alexandria 
Published: May 2020

Magnetohydrodynamics (MHD) is a unique approach for pumping fluids on a microscale and is highly suitable for enabling multiple functions for chemical analysis on a chip. An ionic current, j, is established in the fluid between selectively-activated electrodes in the presence of a magnetic field, B, that is perpendicular to the current, to generate a force, FB
, orthogonal to j and B, through the right hand rule.
FB
is a body force that propels the liquid in the same direction through momentum transfer. We use microelectrodes, which are patterned into different, individually-addressable geometries on chips. Those electrodes are modified with poly(3,4-ethylenedioxythiophene), PEDOT, a conducting polymer, that converts the applied electronic current in the external circuit to ionic current in the fluid [1]. A small NdFeB permanent magnet is placed under the chip to provide B. By strategic activation of the electrodes, fluid flow can be programmable. For example, we previously demonstrated that MHD can start, stop, reverse, adjust speed, and alter profiles of the fluid flow. We have also shown recently that MHD fluid flow can be diverted in a contactless way by magnetic field gradients when paramagnetic species are present [2]. In our presentation, we will discuss how MHD can control the paths of individual microvolumes of different fluids for mixing, sampling, and injection. We will describe the conditions that lead to and the resulting flow profiles that result from adjacent counter flows, transverse paths, and different solvent compositions.

Acknowledgements:

We are grateful for financial support from the National Science Foundation (CMI-1808286) and Arkansas Bioscience Institute, the major research component of the Arkansas Tobacco Settlement Proceeds Act of 2000.

References

[1] Khan, F. Z.; Fritsch, I. “Chip-Scale Electrodeposition and Analysis of Poly(3,4-ethylenedioxythiophene) (PEDOT) Films for Enhanced and Sustained Microfluidics Using DC-Redox-Magnetohydrodynamics”, Journal of The Electrochemical Society
2019, 166 (13), H615-H627.
[2] Hähnel, V.; Khan, F. Z.; Mutschke, G.; Cierpka, C.; Uhlemann, M.; Fritsch, I. “Combining magnetic forces for contactless manipulation of fluids in microelectrode-microfluidic systems:, Scientific Reports
2019, 9:5103.
Simultaneous Determination of Aristolochic Acids in Blood and Tissueby Fluorescence Spectrometry and SERS
Authors: Zhu Lihua , Ouyang Lei , Zhang Qian , Zhao Lei 
Published: May 2020

Aristolochic acids (AAs) contained in herbal plants are implicated in multiple organ injuries and have a high mutational burden in upper tract urothelial cancers. The currently available techniques for monitoring AAs include LC (liquid chromatography) and LC/MS (mass spectrometry), but the application of these approaches are limited due to the complex sample preparation and derivatization steps. Therefore, there is an urgent need to develop efficient methods for identifying and quantifying AAs. Here, we present a new dual-spectroscopic approach for the direct detection of AAs from blood and tissue samples; the detection of aristolochic acid I (AAI) is performed by surface-enhanced Raman spectroscopy (SERS), and its bioproduct, aristololactam (AAT), is detected by fluorescence spectroscopy based on their distinctive spectral response. Furthermore, a graphene assisted enrichment coupled with a magnetic retrieval strategy was developed to enhance SERS sensitivity toward AAI. Our method was successfully applied to directly determine both AAI and AAT from the blood, liver, and kidney of rats. The potential for real-world application was demonstrated by continuously monitoring AAI and AAT in rat blood and tissues after AAI feeding. The results showed that AAI was gradually metabolized to AAT and transported to different organs. It was found that the metabolism of AAI took place in the kidney, but AAT residue was detected in both liver and kidney, which might be related to long-term toxicity and gene mutation. The proposed dual-spectroscopic strategy is applicable to long-term toxicology research and to the direct diagnosis of AAI-induced organ injury.
Fig.1 Illustration of the detection procedure for AAI and AAT in blood and tissue samples.
(Invited) Surface-Confined Electrochemiluminescence Sensing: From Bead-Based Immunoassays to Cell Imaging
Authors: Sojic Neso 
Published: May 2020

Electrogenerated chemiluminescence (ECL) is the process of light emission by the excited state of a luminophore upon electrochemical stimulation[1-2]. To increase the sensitivity and the multiplexing performances of ECL, many efforts have been focused on the development of novel analytical strategies and original imaging applications. In this lecture, we will present a few recent works on biosensing[3-5] and cell microscopy[6-7], which exploit the remarkable characteristics of ECL.
Bead-based ECL assays have been the object of numerous works and they are currently commercialized for more than 150 immunoassays. In a first part, new ECL approaches based either on the light polarisation or on semi-conductors will be presented to extend the performances of ECL[3-4]. In a second part, the development of coreactant-based ECL as a surface-confined microscopy to image single cells and their membrane proteins will be discussed[5-7].
References
1. A. J. Bard. Electrogenerated Chemiluminescence. M. Dekker. 2004.
2. N. Sojic. Analytical Electrogenerated Chemiluminescence: from Fundamentals to Bioassays. Royal Society of Chemistry. 2019.
3. F. Zinna, S. Voci, L. Arrico, E. Brun, A. Homberg, L. Bouffier, T. Funaioli, J. Lacour, N. Sojic, L. Di Bari. Angew. Chem. Int. Ed., 58, 6952 (2019).
4. Y. Zhao, J. Yu, G. Xu, N. Sojic, G. Loget. J. Am. Chem. Soc., 141, 13013 (2019).
5. M. Sentic, M. Milutinovic, F. Kanoufi, D. Manojlovic, S. Arbault, N. Sojic Chem. Sci., 5, 2568 (2014)
6. G. Valenti, S. Scarabino, B. Goudeau, A. Lesch, M. Jović, E. Villani, M. Sentic, S. Rapino, S. Arbault, F. Paolucci, N. Sojic. J. Am.
Chem. Soc., 139, 16830 (2017).
7. S. Voci, B. Goudeau, G. Valenti, A. Lesch, M. Jović, S. Rapino, F. Paolucci, S. Arbault, N. Sojic. J. Am.
Chem. Soc., 140, 14753 (2018).
Electrochemical in-Situ Time Resolved pH Sensing Using Confocal Fluorescent Microscopy
Authors: Pande Nakul , Mul Guido , Lohse Detlef , Mei Bastian Timo , Krug Dominik 
Published: May 2020

In electrochemical reactions, mass-transfer effects due to ion consumption at the electrode are of significance. The concentration gradient thus formed between the electrode surface and the bulk of the solution also contains valuable information about the surface activity and reactivity.
In the context of the hydrogen evolution reaction, H+ ion consumption at the electrode surface increases near-electrode pH, and forms similar gradients between the electrode surface and the bulk. Confocal microscopy has been used in recent years as a tool to measure pH profiles (with a suitable pH probe) near electrodes1–3. The experimental diffusion profiles have generally been compared with a steady state model, and time resolved measurements of the growth of the boundary layer are lacking.
In this contribution, the consumption of H+ ions on a transparent platinum electrode is used to study the one-dimensional growth of the ion depleted boundary layer at different current densities. Using fluorescein as the pH probe, it will be shown that ion concentration can be estimated and hence time-dependent diffusion profiles measured. Furthermore we will highlight the importance of using a pH independent dye to monitor electrostatic effects, which are seen to be significant at low supporting electrolyte concentrations. The experimental results are compared with those of a suitable time dependent reaction-diffusion model. Finally, building on these results, an attempt is made to measure pH profiles around growing bubbles during electrochemical hydrogen evolution with an aim to get further insights into the associated reaction resistances4.
(1) Rudd, N. C.; Cannan, S.; Bitziou, E.; Ciani, I.; Whitworth, A. L.; Unwin, P. R. Fluorescence Confocal Laser Scanning Microscopy as a Probe of PH Gradients in Electrode Reactions and Surface Activity.
(2) Leenheer, A. J.; Atwater, H. A. Imaging Water-Splitting Electrocatalysts with PH-Sensing Confocal Fluorescence Microscopy. J. Electrochem. Soc.
2012, 159 (9), H752–H757.
(3) Bouffier, L.; Doneux, T. Coupling Electrochemistry with in Situ Fluorescence (Confocal) Microscopy. Curr. Opin. Electrochem.
2017, 6, 31–37.
(4) Peñas, P.; van der Linde, P.; Vijselaar, W.; van der Meer, D.; Lohse, D.; Huskens, J.; Gardeniers, H.; Modestino, M. A.; Rivas, D. F. Decoupling Gas Evolution from Water-Splitting Electrodes. J. Electrochem. Soc.
2019, 166 (15), H769–H776.