bluuebunny/crossref_metadata_2025 huggingface dataset:
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.
Benchmark Computations of the Binding Energy of Amino Acids to Benzene: The Role of Water
Authors: Yeates Alan Todd
Published: May 2020

The binding energies of single amino acids to benzene have been computed quantum mechanically using DFT, ccCA-CC(2,3) and ccCA-S4. The goal is to produce binding energies of chemical accuracy that can be used as a comparison with MM force-fields. Even in these small systems we found that water plays a major role in determining the binding energy of the amino acids. A small number of explicit water molecules must be present on the amino acids to accurately model the binding. These water molecules cannot be modeled with a continuum approximation. DFT calculations indicate that approximately two water molecules are needed to saturate the carboxylic acid group and lead to a stable binding energy. In addition it was found that while the zwitterion form of the amino acid is unstable in a vacuum with respect to hydrogen ion transfer, the addition of a single water molecule allows the zwitterion to form a shallow local minimum. We were unable to determine how many water molecules were required to fully solvate the zwitterion.
(Invited) 2D Materials Platform for Gas Sensor and Taste Sensor Arrays
Authors: Jang Ho Won
Published: May 2020

2-dimensional materials including graphene and molybdenum disulfide are fantastic material platform for chemical sensors. In this talk, we want to share our recent advances in graphene-based gas sensors and taste sensors. We emphasize that surface modification and micro-patterning techniques as well as transfer technique are very crucial for obtaining high performance sensing properties. Detailed strategies for demonstrating 2-dimensional materials-based e-tongue and e-nose such will be introduced and prospectives of 2-dimensional materials for high performance chemical sensors will be addressed.
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).
Continuous Manufacturing of Graphene-Contact Ion-Selective Electrodes Using Roll-to-Roll Processes: The Case for Nitrate Sensors
Authors: Oduncu Muhammed Ramazan , Glassmaker Nicholas J , Wei Alexander
Published: May 2020

Soil contains various species of nitrogen, which is crucial for plant growth. Nitrate ion (NO3
-) is essential for promoting high crop yields and is widely used in fertilizers, however groundwater can be polluted by the overuse of nitrate. “Smart agriculture” can be supported by monitoring NO3
- in ground-soil using a distributed network of disposable potentiometric sensors. We have found the performance of such sensors to be enhanced by adding graphene nanoplatelets (GrNPs) as a conductive yet hydrophobic solid contact between the electrode and ion-selective membrane. Exfoliated GrNPs can be stably dispersed in ethyl acetate by liquid-assisted ball-milling, then deposited using methods compatible with the scalable roll-to-roll (R2R) production of ion-selective electrodes (ISEs). Ultra thin layers of GrNPs were formed by spray-coating onto a moving web of screen-printed Ag electrodes on polyethylene terephthalate (PET), followed by in-line deposition of a NO3
- selective membrane and silicone sealant then oven drying. Multiple electrodes from each production run were conditioned in aqueous KNO3 solutions and potentiometric characterizations of sensitivity, selectivity and stability were completed using an 80-channel analyzer. The GrNP layer serves as a hydrophobic transducer of ion adsorption and provides a high capacitance for stable potentiometric signals while also protecting SC-ISEs from damage caused by water permeation. We find that R2R processes can successfully produce graphene-contact NO3
-
ISEs for agricultural applications, with extended operational lifetimes and high levels of quality control.
The Functionalization of Low Dimensional Materials for a Multi-Functional Gas Sensor Platform
Authors: Ambrozik Stephen , Abdelaziz Ahmed , Voskanian Norvik , Raciti David , Ke Ming , Busnaina Ahmed , Sultana Mahmooda
Published: May 2020

Presently, most space missions rely on large, heavy, and high-power instrumentation such as mass spectrometers for chemical analysis on planetary bodies. The weight of these payloads is prohibitive to mission cost, and ultimately hinders scientific advancement. This hindrance has driven us to develop a multi-functional gas sensor platform based on the additive manufacturing of low-dimensional materials. The discovery of low-dimensional materials such as graphene and carbon nanotubes (CNTs) has instigated a push to apply these materials in device design. The unique electrical and physical properties of these materials coupled to their high surface area to volume ratio make them outstanding candidates as extremely sensitive gas sensing elements for both chemiresistive and field effect transistor (FET) based devices. The detection of gases using low-dimensional materials as sensing elements relies on change in the resistance of the sensing element associated with electron donation or extraction by the gas to be detected. For most low-dimensional materials, this mechanism is not especially selective. This lack of selectivity necessitates the functionalization of said materials with catalytically appropriate functional units to promote device selectivity while maintaining the high sensitivity of the low-dimensional materials. We will present our efforts on the functionalization of chemiresistive and FET gas sensors using CNTs, graphene and transition metal dichalcogenides with both physical vapor deposition and solution phase approaches. This functionalization will ultimately allow for the fabrication of an array of gas sensors with each sensor demonstrating varied selectivity for the gases of interest. Our functional group choice, process optimization and ultimately sensor performance will be demonstrated.
(Invited) Fluorogenic Error Correction Code Sequencing: Chemistry, Microfluidics, and Instrumentation
Authors: Huang Yanyi
Published: May 2020

Next-generation sequencing has become a routine tool for biology and medicine. However, eliminating errors in next-generation DNA sequencing has proved challenging. I am going to talk about our newly developed error-correction code (ECC) sequencing, a method to greatly improve sequencing accuracy by combining fluorogenic sequencing-by-synthesis (SBS) with an information theory–based error-correction algorithm. ECC embeds redundancy in sequencing reads by creating three orthogonal degenerate sequences, generated by alternate dual-base reactions. This is similar to encoding and decoding strategies that have proved effective in detecting and correcting errors in information communication and storage. We showed that, when combined with a fluorogenic SBS chemistry with raw accuracy of 98.1%, ECC sequencing provides single-end, error-free sequences up to 200 bp. I also will discuss the recent development we have made on the high-throughput instrumentation of this ECC sequencing approach. We have integrated millions of femtoliter reaction wells into a novel microfluidic platform and have built a prototype upon it to perform high-throughput sequencing experiments such as RNA-seq, non-invasive prenatal screen, and small copy number variation identification.
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.
(Invited) Discrimination and Selective Retrieval of Single Target Cells from the Cell-Based Array
Authors: Yasukawa Tomoyuki , Suzuki Masato
Published: May 2020

Introduction: We have developed manipulation techniques to form cell-based arrays by positive dielectrophoresis (p-DEP) and to retrieve target cells from cell−based arrays selectively by negative dielectrophoresis (n-DEP). The novel devices with microwell arrays on microband electrodes were employed to manipulate cells. Hybridomas with the secretion ability of antibodies were trapped to form cell-based arrays. Then, the ability was discriminated by trapping the antibodies to the antigen immobilized on the bottom of wells. Finally, individual cells trapped in microwells were selectively retrieved by regulating the generation of electric fields in individual microwells. The development of series of these techniques could be useful to recover hybridomas producing antibodies with high affinity in large populations of cells without repeated steps of a culture and a limiting serial-dilution.

Experimental: The device comprises the upper substrate with indium-tin-oxide (ITO) microband electrodes and the lower substrate with microwell arrays on ITO microband electrodes. Hybridomas producing an anti-rabbit serum albumin (RSA) antibody suspended in the DEP medium were introduced in the channel. AC signal (3 MHz, 2 Vpp) was then applied to the upper and lower microband electrodes with opposite phase to form a cell-based array. Anti-RSA antibodies secreted from hybridomas trapped in the microwells were captured by RSA immobilized on the electrodes. Cell arrays were then treated with anti-mouse IgG antibody conjugated with Alexa 488 (a secondary antibody). Thereafter, a repulsive force of negative dielectrophoresis (n-DEP) was employed to retrieve the target hybridomas from the microwell array. To retrieve the target hybridoma, an AC signal in the n-DEP frequency region was applied to a pair of microband electrodes above and below the microwell with the target hybridoma.

Results and discussion: Cell−based arrays were formed with the occupancy efficiency of over 90% in a few seconds by p-DEP. Antibodies secreted in microwell arrays were captured to discriminate target hybridomas in a few hours without repeated steps of a culture and a limiting serial-dilution. Furthermore, hybridomas trapped in microwells were retrieved from the cell−based array by applying an AC signal to band electrodes. The sequential system for forming cell−based arrays, discriminating hybridomas secreting specific antibodies, and retrieving target hybridomas was developed by using the novel microwell array device comprising 3-D microband array electrodes with an orthogonal arrangement.
Plasmon-Enhanced Optical Probes for Sensing of Drug Metabolite
Authors: Boryczka Jennifer , Curtin Kathrine , Wu Nianqiang
Published: May 2020

An Au@SiO2 core-shell nanostar structure decorated with quantum dots was designed and synthesized. This structure displays near-infrared fluorescence and the production of reactive oxygen species when excited. The production of reactive oxygen species can be utilized for photodynamic therapy (PDT), treating cancer. In this work, we utilized this near-infrared fluorescence probe for drug metabolite detection. Drugs are an illicit substance that police, medics, and hospitals need to know if an individual is under the influence of but that individual will not always be willing or able to provide that information. A sensor based on this new optical probe has been developed for detection of drug metabolites in saliva.
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).
(Invited) Why Do Dipole Effects on Charge Transfer Matter?
Authors: Vullev Valentine Ivanov
Published: May 2020

Charge transfer (CT) and charge transport (CTr) are by far among the most important processes for sustaining life on Earth and for making our modern ways of living possible. In natural and manmade sensing systems, for example, well synchronized CT processes drive the conversion of mechanical, optical, chemical and thermal signals into electric outputs, which is essential for interfacing with processing modules. Conversely, electric dipoles are everywhere and therefore, understanding how they affect CT and CTr is of principal importance for attaining and controlling the functionality of a wide range of devices. Discussions of the idea about dipole effects on CT date back to the mid 20th century and reported experimental evidence from the 1990s and 2000s demonstrated their key importance. The dipole-generated localized electric fields induce Stark effects and modulate the electronic properties of the CT moieties in their vicinity. The notion for such effects focusses on dipole-induced changes in the reduction potentials of the donor and the acceptor, affecting the CT driving forces and thus, the Franck-Condon (FC) contributions to the CT kinetics. We recently demonstrated that to harness such effects, which are inherently enormous, (1) the dipoles should be placed as closed as possible to the electron donor and acceptor, and (2) the media polarity should be lowered. Polar media, indeed, stabilize charged states and in general enhances the rates of CT. Polar media, however, screen the field permeation and damps the dipole effect on the electron donor and acceptor. Using hydrocarbons as a medium, results in electron transfer rates along the dipole that are six times larger than the rates for the same system when in polar solvents, such as acetonitrile. The same localized field effects in non-polar medium completely shut down the electron transfer against the dipole. While in the vicinity of dipoles, the electric fields can reach GV/m, they fall off rapidly with distance. In our work, we incorporate the dipoles in the electron donors. This geometry provides the closest possible placement of the dipole to the CT moieties. Most importantly, it has also allowed us to discover for the first time dipole effects on donor-acceptor electronic coupling that dominate and oppose the established notion about effects on the FC contributions to the CT kinetics. These discoveries change the ways of thinking about dipole effects on CT and CTr, and set unprecedented paradigms for the development of electronic materials and devices.
Fabrication of Plasmonic Optical Nanoslit Pore Device for Single Molecule Analysis
Authors: Choi Seong Soo , Lee Yong Min , Oh Sae -Joong , Bae Byung Seong , Kim Hyun Tae , Choi Soo Bong
Published: May 2020

About 60 years ago, the biological cell counter with an electrical detection technique was invented by Dr. Coulter. The solid state nanopores can be fabricated by using various techniques such as ion sculpting, high energy electron beams such as such as field emission scanning microscopy (FESEM) and transmission electron microscopy (TEM). However, this fabricated portable nanopore device is reported to have too high error rates. The high error rates may be attributed to the electrical double layer formed in the nanopore channel. Considering the fact that most biosensors are utilizing the optical detection technique, the optical pore device can be an excellent candidate for the next generation single molecule sensor. we have also fabricated the nanopore with its diameter ranging from 10 to 3 nm inside the FIB drilled aperture by using various surface treatments including electron beam irradiations and ion beam irradiation. In this report, we will address the fabrication of the optical pores with double slits. We observed the nanoscale Young’s interference from the double slits dependent upon the pitch. With increasing the pitch size, the periodic interference phenomena are observed and the optical intensity through the nanoscale slits are also periodically increasing We also fabricated the (7 x 7) hole array with its diameter of ~ 200 nm dependent upon the pitch between the holes with and without the nano- scale double slits. The highest enhancement of 1.72 at the peak is observed at 530 nm pitch without slits, and enhancement of 8.36 at the peak is also observed from the (7 x 7) hole array with a 530 nm pitch with nanoscale double slits. The enhancement of ~ 4-fold increase at the peak can be attributed to the constructive interference between two surface plasmon waves from hole and slits. This device can be utilized as optical manipulation and characterization for nanobio sensor, especially for single molecule analysis

Figure 1
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.
Optofluidic Nanoplasmonic Biosensors for Functional Immune Analysis Towards Next Generation Immunoassays
Authors: Chen Pengyu
Published: May 2020

Building predictive models of immunity requires comprehensive understanding of the complex and dynamic functional behavior of immune system. Cytokines are the key biomolecules secreted by immune cells and essential for intercellular signaling to regulate the diverse functions in the immune response. Rapid and accurate quantification of cytokine-based immune fingerprints provides clinically and immunologically useful information related to infectious diseases, cancer, autoimmune diseases, and allergy transplantation. Current "gold standard" method based on Enzyme-linked immunosorbent assay (ELISA) requires time-consuming sample labeling and washing processes, resulting in long assay time and can only provide snapshot signal readouts at the end of the measurement. Thus, there is an emerging clinical demand for transformative platforms that can perform multi-parametric cytokine detection to understand the dynamical immune response of the patient in a rapid and accurate manner. In this presentation, we will introduce a number of novel plasmonic nanomaterial based optofluidic biosensing platforms that can perform rapid, high throughput, sensitive and multiplex cytokine detection from whole blood to single-cell level. The multi-scale research both experimentally and theoretically will bridge the gap in fundamental understanding of immune system and enhance the applicability, diagnosis and prediction power for immune system diseases. The developed platforms would ultimately gear the biologists and clinicians with capability to real-time monitor the immune status in patients, a transformative achievement that has enormous implications to fundamental research and clinical applications.
Trace Level Chemicals Detection By Surface-Enhanced Raman Scattering
Authors: Zhang Zhengjun
Published: May 2020

The Raman signals of molecules attached on the very surface of noble metals nanostructures can be greatly enhanced due to the enhancement of the local electric field, by the localized surface plasmon resonance of the nanostructures incident by the laser beam. Therefore, one can make Raman scattering a powerful means in recognizing and quantifying molecules at trace levels. This, however, relies on the sensitivity, stability, etc., of the nanostructures which are used as the substrate surface-enhanced Raman scattering, and also, the methodologies to quantify the molecules, which are quite difficult even for normal Raman scattering. We report here, our attempts to design and fabricate silver nano rods as substrate for surface-enhanced Raman scattering, with very high sensitivity, thermal and chemical stability, excellent reusability, etc., which can be used in real application environments, and efforts to establish approaches for qualitative and quantitative analysis of chemical mixtures at trace levels by surface-enhanced Raman scattering. Several examples will be also shown for trace level analysis of real samples by surface-enahnced Raman scattering with the approaches established.
Recovering from Precipitation Events in Redox Flow Batteries
Authors: Saraidaridis James D , Yang Zhiwei , Darling Robert M. , Perry Mike L.
Published: May 2020

Liquid electrolyte solutions containing dissolved active material imbue Redox Flow Batteries (RFBs) with many unique benefits relative to solid-state electrochemical energy storage devices: long shelf-life, long system life-time, de-coupled rated energy and power, ease of recyclability.1 Operating a RFB system with flowing electrolyte solutions presents unique concerns as well, with one notable concern arising from possible precipitation of electrolyte. Precipitation of active material can have many consequences including sensor inaccuracy, inaccessible storage capacity, partially- or fully-blocked reactor electrode regions, and system clogging.

Aqueous vanadium RFBs, a leading chemistry in commercial systems, has a precipitation mechanism at high temperatures for battery solutions containing commercially relevant vanadium concentrations >1.5 M. At elevated temperatures (> 40°C), positive electrolyte solutions can precipitate V2O5 dimers, first as a gel-like substance and eventually as solid particles.2 The UTRC team has developed recovery procedures for systems that may succumb to such precipitation events; in the case for aqueous vanadium RFBs, exposure of precipitate to lower oxidation state forms of vanadium (i.e. negative electrolyte) reduces and redissolves precipitated V2O5. This electrolyte takeover process (ETP) can successfully redissolve precipitates and recover performance from precipitate-induced cell/stack under-performance.

As UTRC pursues alternative flow chemistries, the same ETP principles are applied to other chemistries such as polysulfide-based systems, known for sulfur crossover and precipitation of elemental sulfur in positive electrode volumes.3 This abstract will discuss the progress made at UTRC to recover from precipitation events in such chemistries, which, unlike aqueous vanadium, do not permit simple mixing of negative and positive electrolytes.

Acknowledgements:

The authors gratefully acknowledge support from Vionx Energy Corporation. Some of the work to be presented here was funded by the Advanced Research Projects Agency - Energy (ARPA-E), U.S. Department of Energy (DOE) under Award Number DE-AR0000994.

References:

1. Chalamala, B. R.; Soundappan, T.; Fisher, G. R.; Anstey, M. R.; Viswanathan, V. V.; Perry, M. L., Redox Flow Batteries: An Engineering Perspective. Proceedings of the IEEE
2014,
102 (6), 976-999.

2. Skyllas‐Kazacos, M.; Menictas, C.; Kazacos, M., Thermal Stability of Concentrated V(V) Electrolytes in the Vanadium Redox Cell. Journal of The Electrochemical Society
1996,
143 (4), L86-L88.

3. Su, L.; Badel, A. F.; Cao, C.; Hinricher, J. J.; Brushett, F. R., Toward an Inexpensive Aqueous Polysulfide–Polyiodide Redox Flow Battery. Industrial & Engineering Chemistry Research
2017,
56 (35), 9783-9792.
Nitrogen-Doped Carbon Supported Mn-Co Nanoparticles for Supercapacitors Application
Authors: Balčiūnaitė Aldona , Budrytė Eivilė , Vaičiūnienė Jūratė , Kruusenberg Ivar , Kaare Kätlin , Volperts Aleksandrs , Dobele Galina , Zurins Aivars , Tamašauskaitė-Tamašiūnaitė Loreta , Norkus Eugenijus
Published: May 2020

In this study, the microwave-assisted heating method has been used for the synthesis of nitrogen-doped carbon (N-doped C) supported Mn-Co nanoparticles with the aim to use it as the electrode material for supercapacitor application. N-doped C has been obtained from alder wood chips as the biological waste. At first, activated high surface area carbon has been obtained by using chemical activation method with NaOH at higher temperatures, followed by nitrogen doping at a temperature of 800 оС by using dicyandiamide (DCDA) as a nitrogen precursor. It should be noted that the prepared N-doped C has a graphene-like structure. Then, Mn-Co nanoparticles have been deposited on the N-doped C surface using microwave-assisted heating.

The Mn-Co@N-doped C nanocomposites have been characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS) and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Moreover, electrochemical performance has been investigated by cyclic voltammetry (CV) in a 1 M Na2SO4 solution at the scan rates of 1, 5, 10, 20, 100 and 150 mV s−1.

It was found that the obtained specific capacitance (C
s) value for the Mn-Co@N-doped C nanocomposite was equal to 497.5 F g−1 at a scan rate of 1 mV s−1 and decreased to 254.4 F g−1 at a scan rate of 150 mV s−1. The Mn-Co@N-doped C nanocomposite preserves 51.1 % of its specific capacitance as the scan rate increases from 1 mV s−1 to 150 mV s−1. The obtained results confirmed a good performance of the prepared Mn-Co@N-doped C nanocomposite as the electrode material for supercapacitors application.
Investigating the Redox Properties of a Bio-Inspired Vanadium-Based Non-Aqueous Flow Battery Electrolyte
Authors: Gokoglan Tugba Ceren , Pahari Shyam K. , Cappillino Patrick J , Agar Ertan
Published: May 2020

Redox flow batteries (RFBs) have been identified as a promising large-scale energy storage technology to enable the transition toward a carbon-neutral electricity grid [1]. Among various types of RFBs, non-aqueous redox flow batteries (NRFBs) have the potential to reach the energy density of lithium-ion batteries, while maintaining the advantages of flow systems, including decoupled power and energy rating and efficient long-duration storage [2]. Despite the potential of this transformative technology, poor active material stability poses a fundamental obstacle to NRFB research progress [3-4]. Furthermore, low active material concentrations negate high theoretical energy densities made possible by the wide electrochemical windows of non-aqueous electrolytes [5].

To simultaneously address these issues, we have recently developed an active material based on a molecule known as Amavadin that is naturally occurring in mushrooms of the Amanita genus. Biosynthesis of this molecule evolved to bind vanadium selectively and with the highest stability ever reported. Synthetic analogs of Amavadin are synthesized in our lab (vanadium(iv) bis-hydroxyiminodiacetate ([VBH]2-)), using inexpensive reagents, at large scale, with high yield and are implemented as a high-stability scaffold for NRFB development [3]. This study aims to elucidate the electrochemical behavior of the introduced NRFB electrolyte at elevated concentrations using an ultramicroelectrode technique. The general trends of critical redox properties of symmetric, [NXXXX]2[VBH] compounds (x = 1 to 4) are systematically investigated to provide fundamental insight into NRFB electrolyte dynamics. Finally, the performance characteristics of the [VBH]-based electrolytes will be demonstrated using operando flow cell data.

References:

1. L. Soloveichik, Chem. Rev., 2015, 115 (20), 11533-11558.

2. J. Cappillino, H. D. Pratt, N. S. Hudak, N. C. Tomson, T. M. Anderson, M. R. Anstey, Adv. Energy Mater., 2015, 4 (1), 1300566.

3. Huang, R. Howland, E. Agar, M. Nourani, J. A. Golden, P. J. Cappillino, J. Mater. Chem. A., 2017, 5, 11586-11591.

4. C. Gokoglan, S. K. Pahari, A. Hamel, R. Howland, P. J. Cappillino, E. Agar, J. Electrochem. Soc., 2019, 166 (10), A1745-A1751.

5. H. Attanayake, J. A. Kowalski, K. V. Greco, M. D. Casselman, J. D. Milshtein, S. J. Chapman, S. R. Parkin, F. R. Brushett, S. A. Odom, Chem. Mater., 2019, 31, 4353-4363.
(Invited) Redox Flow Batteries: Commercial Operation and Research Developments
Authors: Lin Ian
Published: May 2020

In recent years, climate change has driven the development of renewable energy sources. As a result, an increase in need for storage technologies to complement large scale implementation of solar and wind power has been realized. Targeting the diversification of storage technologies and the provision of consistent power for the energy grid, Sumitomo Electric Industries has been expanding resources into the development of the redox flow battery.

Lately we have had some success installing Vanadium based Redox Flow batteries worldwide, with projects in Belgium, Morroco, Taiwan, and USA. One of the most recent projects, a microgrid project in Ouarzazate, Morocco, features a 125kW by 4h flow battery system with PVs and continues to run in collaboration with our partners UNIDO (United Nation Industrial Development Organization) and Masen. Projects including a 1.5MWh system in Belgium, an 8MW system in California, and a 60MW system in Hokkaido, are reported to have had no significant difficulties in operation thus far.

Looking forward with research, possibilities in exploring low-cost electrolytes are currently being pursued. We at Sumitomo Electric Industries are pushing forward research of a Titanium Manganese flow battery. So far, success in scaling up lab scale results to a 10 kW class cell stack has been realized, confirming an energy density of 14 kWh/m3 over 139 cycles with an energy efficiency of 82.5% at a current density of 200 mA/cm^2; however, during these cycles a decrease in OCV was observed. It was hypothesized that the decrease observed OCV is reflective of the disproportionation reaction of Mn3+ (the charged state of the active ion in the positive electrolyte) into MnO2 solid precipitate. To test this hypothesis, recovery of OCV was shown by the discharge of electrolyte to low SOCs for extended periods of time. This has prompted our further research and development into methods to control precipitation of MnO2 and subsequently improve the TiMn electrolyte for redox flow battery technologies.
Developing New Chemistries for Redox Flow Batteries (AORFBs)
Authors: Liu T. Leo
Published: May 2020

Aqueous organic redox flow batteries (AORFBs) have emerged as an attractive alternative RFB technology because redox active organic molecule materials are synthetically tunable, sustainable, and potentially low cost. The presentation will cover our recent research efforts in developing viologen anolyte materials for both anion and cation exchange pH neutral AORFBs with a variety of catholyte materials including ferrocene, TEMPO, ferrocyanide and halides. The viologen AORFBs demonstrated outstanding battery performance including an energy density of up to 30.4 Wh/L, a power density up to 220 mW/cm2, energy efficiency up to 72% at 60 mA/cm2, and capacity retention up to 99.999% per cycle up to 1000 cycles, representing the most stable organic RFB reported to date. In addition, this presentation will discuss mechanistic understandings of investigated redox active molecules using a variety of spectroscopic tools. Particularly, the presentation emphasizes that fundamental understandings of redox active electrolytes at molecular level are crucial to develop new generations of redox flow batteries for large scale and dispatchable renewable energy storage.

References: (1) Luo, J.; Hu, B.; DeBruler C.; Yuan, B.; Zhao, Y.; Hu, M.; Wu, W.; Liu, T. L.* Joule, 2019, 3, 1-15. (2) Luo, J.; DeBruler C.; Hu, B.; Hu, M.; Wu, W.; Liu, T. L.*,J. Mater. Chem. A, 2019,7, 9130-9136. (3) DeBruler C.; Hu, B.; Moss, J.; Luo, J.; Liu, T. L.*, ACS Energy Letters 2018, 3, 663-668. (4) Luo, J.; Hu, B.; DeBruler C.; Liu, T. L.*,Angew. Chem. Int. Ed. 2018, 57, 231-235. (5) Hu, B.; Tang, Y.; Luo, J.; Grove, G.; Guo, Y.; Liu, T. L.*,Chem. Commun. 2018, 54, 6871-6874. (6) Hu, B.; Liu, T. L.* J. Energy Chem. 2018, in press. (7) DeBruler C.; Hu, B.; Moss, J.; Liu, X. Luo, J.; Sun, Y; Liu, T. L.*, Chem, 2017, 3, 961-978. (8) Luo, J.; Sam, A.; Hu, B.; DeBruler C. Liu, T. L.* Nano Enegry, 2017, 42, 215-221. (9) Hu, B.; Seefeldt, C., DeBruler C.; Liu, T. L.*, J. Mater. Chem. A 2017, 5, 22137-22145. (10) Hu, B.; DeBruler C., Rhodes, Z.; Liu, T. L.*, J. Amer. Chem. Soc., 2017, 129, 1207-1214. (11) Liu, T.;* Wei, X.; Nie, Z.; Vince, S.; Wang, W.* Adv. Energy Mat. 2016, 6, 1501449.(12) Filed US Patents covering applications of water soluble viologen, ferrocene derivatives, and TEMPO for RFBs. (13) Group website: www.tianbiaoliu.org.
Pulsed Charging Protocol for a High Efficiency Zinc - Iron Rechargeable Flow Battery
Authors: Accogli Alessandra , Bertoli Luca , Panzeri Gabriele , Gibertini Eugenio , Magagnin Luca
Published: May 2020

Flow batteries (FBs) are one of the most promising stationary energy‐storage devices for storing renewable energy. However, commercial progress of FBs is limited by their high cost and low energy density [1,2]. Therefore, the development of new flow battery systems with low cost, high energy density, and excellent electrochemical performances it is crucial [3,4]. Zinc and iron are two common elements that have abundant reserves in the earth’s crust, and they have outstanding electrochemical properties as well. Owing to the high solubilities of the zinc and iron salts, the battery has the potential of achieving a high energy density [1-3].

In this work, a zinc-iron flow battery in a two compartments setup is presented. In particular, the use of a new electrolyte as mild acidic solution for zinc electrodeposition with high cathodic efficiency will be shown. The effect of additives on the electrolytes electrochemical behavior has been characterized by means of cyclic voltammeries while the battery performances have been evaluated by galvanostatic charge and discharge tests. Results revealed that the mid acidic flow battery exhibited a stable energy efficiency higher than 70% over many cycles at a current density of 25 mA cm−2. Moreover, the employment of pulsed charge, i.e. pulsed Zn plating, on cycles efficiency and battery performances will be shown.