bluuebunny/crossref_metadata_2025 huggingface dataset:
Oer/ORR Properties of Massively Synthesized Nimos with Solvothermal Method
Authors: Choi Yusong , Ahn Tae-Young , Kim Jiyoun , Cho Janghyeon
Published: December 2020

The oxygen electrode is the most critical component in lithium-air batteries for oxygen reduction and evolution reaction (ORR/OER) in order to get closer to the theoretical energy density of 11,238 Wh/kg, which is the best among the batteries ever developed. Many carbon materials have been researched as a candidate oxygen electrode for lithium-air batteries such as a carbon black, CNTs, and graphene. Compared to the many research results, there are still many controversies on the optimum oxygen electrode for lithium-air batteries. Besides that, carbon and binder have been known to deteriorate OER/ORR properties for lithium-air batteries by generating Li2CO3 and other bi-product.

Recently, HER and OER properties of heterogeneous MoS2/Ni3S2 have been reported for water splitting. The heterogeneous HER and OER performances of MoS2/Ni3S2 were better than the commercial HER and OER catalysts. Up till now, to my best knowledge, there is no report on ORR properties for homogeneous NiMoS. Therefore, in order to research the ORR properties of homogeneous NiMoS, the homogeneous NiMoS has been synthesized on Ni-foam and Ni-powder by various solvothermal methods such as applying stirring during solvothermal synthesis, increasing the pressure or applying the both. Finally, we successfully synthesized NiMoS massively with stirring at the pressure of 15 bar. Characterization for NiMoSs variously synthesized were conducted with SEM, TEM as well as OER/ORR properties using RRDE (Ring Rotating Disk Electrode).

As a result, homogeneous NiMoSs massively synthesized with stirring as well as high pressure of over 15 bar shows a unique homogeneous structure with sub-micron size. However, NiMoS synthesized under 2~3 bar pressure with no stirring shows the tens of micron size as well as heterogeneous structure. Intriguingly, OER/ORR properties of massively synthesized NiMoS shows much better OER/ORR properties compared to the solvothermally synthesized NiMoS with no-stirring and 2~3 bar pressure. These results show a very positive result for non-precious electrode material for next-generation Li-air battery as well as fuel cell field.
Silicon Microfabricated Preconcentrator Design and Characterization
Authors: Hesketh Peter J. , Struk Daniel , Paik Seung Joon , Navaei Milad , Chang Tzu-Hsuan , Doroshenko Vladimir M. , Dimandja Jean-Marie D.
Published: December 2020

Abstract

MEMS fabrication technology has been applied to build micro-GC systems for portable analysis and detection of volatile organic compounds for environmental monitoring, medical diagnostics and food safety and security (1). Pioneering work at Sandia National Laboratories developed - these miniature systems (2). Novel designs for pre-concentrators have been developed to provide efficient sample injection into these systems (3). We have integrated a 6m length micro-GC column with an ion trap mass spectrometer (4). To inject the sample into the column, our initial method was to use a syringe injection into a heated septum with Agilent 6890. However, for automated operation and method of sampling, pre-concentration of the volatile organic compounds is required, followed by rapid heating, for sample injection for analysis. A microfabricated pre-concentrator can fulfill this function by providing a high surface area in a compact platform with reduced thermal mass, compared to commercial desorption tubes. The design has an integrated platinum heater and was fabricated using standard photolithography, deep reactive ion etching and wafer bonding. To evaluate the performance, the pre-concentrator is mounted inside a commercial Agilent 6890 GC system. Liquid injections 0.02uL, using a syringe, with a 100:1 split, at a helium flow rate of 0.005 ml/min. The flow rate was increased during the desorption cycle, and the preconcentrator was heated by electrical current of providing approx. 5W to enable rapid heating to 180°C. This miniature pre-concentrator provides a small thermal mass design and was capable of fast desorption of several analytes with detection by FID.

References

[1] M. Akbar, M. Restaino, M. Agah, “Chip-scale gas chromatography: From injection through detection,” Microsystems Nanoengineering, Vol. 1, pg. 15938 (2015).

[2] in J. J. Whiting, E. B. Myers, R. P. Manginell, M. W. Moorman, K. Pfeifer, J. M. Anderson, C. S. Fix, C. Washburn, A. Staton, D. Porter, D. Graf, D. R. Wheeler, J. Richards, K. E. Achuythan, M. Roukes, R. J. Simonson, "μChem Lab: twenty years of developing CBRNE detection systems with low false “μChemLab: twenty years of developing CBRNE detection systems with low false alarm rates”Proceedings of SPIE, Vo.l. 11010, Chemical, Biological, Radiological, Nuclear, and Explosives (CBRNE) Sensing XX, 1101012 (17 May 2019); doi: 10.1117/12.2518778.

[3] Tian, Wei-Chang, H. K. L. Chan, Chia-Jung Lu, S. W. Pang, E. T. Zellers, “ Multiple-stage microfabricated preconcentrator-focuser for micro gas chromatography system,” J. Microelectromachanical Systems, Vol. 14, No. 3, pp 498-507 (2005).

[4] Tzu-Hsuan Chang, D. Struk, M. Navaei, V. M. Doroshenko; V. Laiko; E. Moskovets; K. Novoselov, J. D. Dimandja, Peter J. Hesketh, “Separation of Volatile Organic Compounds using of MEMS-GC Integrated Heater for Ion Trap Mass Spectrometer,” Sensors and Actuators B, Vol. 307, pg. 127588 (2020).
A Rapid Identification and Counting Method for Particle Sensing Using Machine Learning
Authors: Oztemel Muhammed , Park Jason D , Choi Jin-Woo
Published: December 2020

Cell identification and counting is important in all cell-related research steps including but not limited to culture, transformation, transfection, protein expression, etc. for cancer studies, disease diagnostics, bacterial detection, and so on. Although hemocytometry has been a traditional and conventional method of counting cells, it is tedious and laborious in general and often provides inaccurate counting. Flow cytometry is a far advanced and accurate method in cell counting but it requires an expensive and delicate instrument. Additionally, flow cytometry cannot be applicable to in situ cell counting. Image analysis is another method in cell counting, which has recently been developed but often suffers from inaccuracy for nonhomogeneous cell populations. In this work, we propose a rapid cell identification and counting method using image analysis and machine learning.

This abstract presents preliminary results of a novel approach for counting spherical particles in a mixed population having spherically- and oddly-shaped particles using a machine learning technique based on convolutional neural networks (CNN). The proposed methodology utilizes segmentation of particles through scanning the input image in order to recognize and count spherically-shaped particles. Convolution layers process input images with respective filters to identify the shapes of the particles. Parameters of the filters (weights) are adjusted by the learning algorithm to extract different features of interest. Subsequently, a pooling procedure is applied for selecting identified features, in which the selected region is represented by the max or the average intensity of the scanned region in the input image. Both convolution and pooling procedures are applied multiple times in order to obtain better recognition and counting. Upon completing this learning process, features are fed into fully connected layers.

Threshold segmentation and canny edge detection methods are applied in order to obtain a particle pattern of each selected shape to train the CNN. Particles having two different shapes, i.e., spherically- and oddly-shaped particles, are used for preliminary investigation. Data augmentation is used to create subsets of image data for training. After training the algorithm, an image containing many particles in different shapes was tested in order to assess the performance of learning process. Each particle was detected and segmented by a pixel size of 25 x 25.

Preliminary results show that CNN has performed promising performance for identifying spherically shaped particles while massive images are currently being gathered and used for training to improve the accuracy. Additionally, initial findings indicate that machine learning could improve cell recognition and counting in biomedical research including cell population sensing. We intend to include a variety of particle shapes for generic cell identification and counting.
Fabrication of Copper Oxide Modified Graphene Composite Sensor for Simultaneous Detection of Biometabolites from Urine
Authors: Eduok Ubong
Published: December 2020

It is a common knowledge that the concentration of certain biomarkers in the body accounts for the presence of some diseases. For instance, the unusual levels of uric acid in body fluids may be indicative of gout and hyperuricemia. These biomarkers may be present within the body but may not be detected at very low concentrations and on time to enable proactive treatments, and the consequences may be dire. The current research report features a new approach developed towards fabricating a new copper oxide modified graphene composite sensor with unique nanostructures on a pencil electrode for sensing three biometabolites (xanthine, uric acid and urea) in urine at very low limit of detection (LOD). The surface structures of this composite sensor composed of several electroactive sites for adsorption of desired analytes. This sensor was appropriately characterized by means of Raman spectroscopy, scanning electron microscopy, cyclic voltammetry as well as localized and normal electrochemical impedance spectroscopy. This sensor was significantly sensitive towards uric acid ((LOD = 10 ppm) and urea (LOD = 20 ppm) sensing compared to xanthine (LOD = 50 ppm). Optimization of key sensor parameters towards efficient sensing (e.g. CuO content) were also examined. The efficiency of the composite sensor toward sensing these analytes in the presence of potential interference was investigated using real human urine. Biomolecular sensing of disease biomarkers at low LOD is important in the assessment of health conditions and monitoring treatment progress of patients. Our experimental results demonstrate the efficacy of simultaneously sensing multiple analytes in a complex biological sample.

Keywords:

Biosensing; Simultaneous detection; Biometabolites; Disease biomarker; Limit of detection
An Allosteric Transcription Factor-Based Electrochemical Progesterone Sensor
Authors: Sankar Karthika , Baer R , Grazon Chloe , Klapperich Catherine M. , Galagan James , Grinstaff Mark W
Published: December 2020

There is an immense potential for using biosensors in medical diagnostics as well as industries like pharmaceutical, food, beverages, environmental, and agricultural. Today, there remains a significant challenge to meet low levels of detection without compromising simplicity and affordability. Hormone measurements play a central role in family planning programs benefiting millions of women, and in monitoring endocrine disorders. Progesterone is a steroid hormone secreted by the corpus luteum and tracking progesterone levels during an ovulation cycle is beneficial for increasing fertility odds. Furthermore, during pregnancy, progesterone balance helps nurture and develop the fetus. Currently, there are no convenient and cost effective point-of-care (POC) devices to detect progesterone: antibody based approaches are used for progesterone sensing but their use is limited by high cost, production duration, and unreliability. This work has led to the development of in vitro biosensors based on bacterial allosteric transcription factors (aTFs). Like antibodies, aTFs recognize analytes with high sensitivity and specificity. In contrast to antibodies, aTFs respond to analyte binding by changing their affinity for a cognate DNA sequence. Using a novel progesterone-specific aTF, and its binding affinity to a specific DNA sequence provides an intrinsic electrochemical transduction mechanism for the development of novel progesterone biosensor. An electrochemical transduction method offers higher sensitivity and specificity at low cost. The biosensor surface includes a gold electrode with a surface immobilized DNA-aTF complex. During electrochemical measurements using a negative redox mediator (ferrocyanide/ferricyanide complex), in the absence of progesterone the overall negative charge of DNA-aTF complex blocks the negative mediator, prevents exchange of electrons with gold electrode, and generates lower current output. Addition of analyte or progesterone alters the affinity binding of DNA-aTF, releases the aTF from the surface, and enables the mediator to reach the surface, thereby resulting in an amplified current output. Preliminary results using our biosensor yielded a limit of detection of 33 nM over a physiologically relevant range of 0-10 µM progesterone in buffer, and 44 nM in presence of interferents in artificial urine.
Composite Coating on Au Inverse Opals As a Highly-Sensitive Enzyme-Free
Authors: Chung Wei-An , Hung Pei-Sung , Chou Shih-Cheng , WU Chieh-Jui , Guo Wei-Qing , Wu Pu-Wei
Published: December 2020

The detection of hydrogen peroxide (H2O2) is of practical importance due to its involvement in the functioning and signal transduction of living cells. Various electrochemical techniques have been explored using either enzymatic or non-enzymatic sensors. In particular, non-enzymatic biosensors have attracted considerable attention because of their impressive stability and reproducibility. In addition, they are less susceptible to environmental interferences. However, the primary drawback of non-enzymatic sensors is poor sensitivity and selectivity. Hence, we want to address this issue by fabricating Cu2O in an inverse opaline structure. Our process involves the preparation of Au inverse opals serving as a three-dimensional ordered macroporous conductive substrate that allows an excessive surface area and sufficient porosity for mass transport. The Cu2O is electrodeposited on the Au inverse opals for the detection of H2O2. Comprehensive electrochemical analysis and materials characterization are conducted and discussed.
Wide-Detectable Range Electrochemical Immunosensor in PPQ to PPM
Authors: Sato Yosuke , Johmen Masayoshi , Takahashi Masashi , Kawaguchi Toshikazu
Published: December 2020

In this research, we propose the concept of electrochemical immunosensing. The typical antibody had a difficulty to detect a small analyte. In conventional method, the Fab region of antibody is extracted after the decomposition of antibody, however it is still difficult to apply in the detection of tiny analyte. In this research, we propose here a use of only a biorecognition element of antibody for immunoassay. In recent, our research group developed the synthesis method of variable domain ofheavy chain of heavy-chain antibody (VHH antibody) from Brevibacillus with enzyme. VHH antibody is a recognitionpart of antibody. Thus, it is physically and chemically stable, and heat-resist characteristic.Here, the electrochemical immunosensing of ovalbumin (ca. 14 nm) is demonstrated. OVA VHH antibody was newly synthesized for this research.The sensor chip is updated into planar-sensor chip. Four electrodes are assigned forming ring on the chip surface. All the substrate of electrodes were made from Au on Cu. The whole size of this sensor chip is 105 mm x 11 mm. Both counter electrode and reference electrode are Au.

Working electrode was mixed monolayer of VHH antibody-propanethiol/Au, ferrocenyl-propanethiol/Au, and ethanolic-propanethiol/Au. Ethanolic-propanethiol was used for prevention of non-specific adsorption of protein.Ferricyanide plays a role in the promoter for redox reaction of ferrocene.Once the electrochemical immunosensor chip was contacted with OVA standard solution (1 ppt to 10 ppm of OVA in PBS solution), and then the chip was rinsed with PBS solution. And then, cyclic voltammogram was obtained in 0.1 M NaCl electrolyte solution. For further amplification of the signal, ferricyanide was added to the electrolyte solution. Figure 1 illustrates cyclic voltammograms of electrochemical immunosensor after dumping with OVA standard solution in the range from 1 ppt to 10 ppm. The OVA VHH antibody captured OVA in the process of antigen- antibody reaction. As a result, captured OVA blocked the redox reaction of amplifier. It can be observed in the Figure 1 as a delay and decay of the peak. Regeneration of the surface of the sensor chip was completed except for yellow line (100 ppt, Figure 1).It means that when the regeneration succeeded, we can make use of this sensor chip again in another measurement.Two kind of calibration plots were obtained from the current density at +0.35 V and the peak potential in Figure 1.It can distinguish from each peak from 1 ppt to 10 ppm. It means to be able to detect in the broad range.Another plot of the anodic current at +0.35 V showed that the OVA of 0 to 10 ppt could be very sensitively detected.It is critical that this sensor chip is valuable because of its sensitivity, repeatability, reproducibility, and compact. It can be presumed that it can apply to real-time sensing or detection of ultra- micro substance in the organisms.
Electrochemical Treatment Characteristics of Insoluble Anode Electrode By Surface Morphology
Authors: You Mi-Young , Song Chang Weon , Choi Young Joong , Song Pung-Keun
Published: December 2020

The sewage and wastewater treatment market has evolved from organic matter removal to advanced treatment and high reuse markets, and has developed into a treatment system that covers toxic control and optimal treatment of non-degradable materials. The importance of advanced treatment of sewage and wastewater treatment facilities is increasing, and the additional cost of sludge disposal becomes an important economic factor in the operation of sewage treatment plants. Moreover, as marine dumping of organic wastes has been banned since 2013, it is urgent to reduce the amount of sludge generated due to land treatment. In order to reduce the amount of sludge generated, volume reduction of the sludge is absolutely necessary, and dewaterability of the sludge is essential for volume reduction of the sludge. Dewaterability of sludge generally depends largely on the physical and chemical properties of the sludge, such as the charge of the particles of the sludge, the content of bound water, the content of solids and organics, the size and mechanical strength of the particles, porosity, and compression coefficient. In addition, conditions such as the type of modifier and dehydration pressure and speed are greatly affected. The free water present in the sludge can be discharged to the outside relatively easily, but it is insufficient to remove the bond by being present in the capillaries inside the sludge or by binding to substances in the sludge cells. Therefore, in this study, to solve the shortcomings of IrO2 and Pt electrodes, which are industrially insoluble anode electrodes, boron-doped diamond (BDD) was selected to study the dehydration efficiency of the dewatered sludge cake and the treatment characteristics of refractory organics.

BDD electrodes with excellent mechanical properties, non-toxicity, and a wide potential window were deposited by HFCVD on Ti substrates with interlayers and Nb substrates for characterization according to the substrates. The surface morphology of the BDD electrode was controlled through the pressure during deposition, and a comparative study of the treatment properties with the previously used IrO2 electrode was conducted. The sewage sludge dewatering cake exhibiting an initial water content of 80% was treated under 50V and 1 min conditions. Upon treatment, the IrO2 electrode exhibited a 5% removal rate, and the BDD electrode exhibited a 50-60% removal rate.
Spectroelectrochemical Study of Organic-Inorganic Hybrid Nano-Molecular Clusters Exhibiting Voltage-Gated Fluorescence Switching and Electrochromism
Authors: Madugula Dronareddy , Wang Teng Wei , Lee Mark W
Published: December 2020

Polyhedral boranes especially the twelve vertex closo-dodecaborate and the ten vertex closo-decaborate anions exhibit remarkably high thermal stability and resistance to oxidative degradation. Such high stability is attributed to the extensive delocalization of their framework bonding electrons, giving rise to three dimensional aromaticity. The substitution chemistry of polyhedral boron chemistry using aromatic ligands was previously limited in scope. However, we recently reported new and extensive polysubstitution chemistry for these ions. The structural characterization of the products revealed that up to ten of B-H vertices may be replaced with phenyl, substituted phenyl, or polycyclic aromatic hydrocarbons as ligands through the formation of stable boron-carbon bonds. The resulting organic-inorganic hybrid nano-molecular ions are pseudospherical whose diameters range between 1.3 – 3.5 nanometers depending on the ligands involved. These polyarylborane clusters are found to exhibit interesting electronic and spectroscopic properties, including high solution-phase fluorescence quantum yields, high molar absorptivities, and extraordinarily large stoke shifts. Furthermore, the fluorescence emission, excitation and absorption spectra for most of these products change reversibly upon applying product-specific electrochemical potentials, thus resulting in redox-controlled fluorescence switching and electrochromism. The properties of each polyarylborane depend upon the composition and the structure of the bound ligands, and these may be tailored through chemical modification of the surface. Our study suggest that these new nanomaterials may have potential for applications in biomedical imaging and sensor development. This presentation will focus on the details of syntheses, structural characterization, electrochemical and spectroelectrochemical properties of polyarylboranes.
Observing the Current Change with Increasing Temperature in Thermo-Responsive Polymer Solution Using Electrochemical Method
Authors: Song Sua , Kim Byung-Kwon
Published: December 2020

The behavior of redox in thermo-responsive polymer solution while heating was electrochemically observed and analyzed in this research. Temperature responsive polymers are intensively applied to various research fields and industries such as drug carriers, lithium ion batteries, temperature sensitive films, and sensor technology. For this reason, measuring the critical point and analyzing the phase transition of temperature stimuli responsive polymer are very important.

In previous studies, the phase behavior of polymers according to the temperature was examined by measuring the transmittance of solution using ultraviolet–visible (UV-vis) spectroscopy and the size of polymer particles in solution using dynamic light scattering (DLS). As an electrochemical method, a collision method was used for detecting current decrease caused by aggregated polymer which blocked the electrode surface. These methods, however, were unable to track the behavior of polymer in solution during continuous temperature increase in real time easily. The temperature was increased at intervals of 5 ℃ to measure the absorbance of solution in UV-vis spectroscopy and only specific temperature and time could be used to observe the blocking signal in the electrochemical collision method. In this study, we offer the easy and novel way to monitor the thermal induced change of polymer and redox with continuous temperature increase using the electrochemical system.

Lower critical solution temperature (LCST) polymer was used as the thermo-responsive polymer in this research. Dissolving the LCST polymer in organic media containing the redox, we measured the current with increasing temperature in real time. The experiment was conducted using electrochemical method with an ultramicroelectrode (UME) and the current transition according to the temperature growth was monitored. As a result, the specific current changes were obtained. Analyzing these specific current changes can be used to confirm the phase transition behavior of the temperature responsive polymer and redox in polymer solution. This study will be applied for further research with controlling the various conditions.
Electrochemical Detection of Apolipoprotein A1 As an Alternative Method to Diagnose Early Stage of Bladder Cancer Patients
Authors: Kim Seong-Eun , Hwang Seiyoung
Published: December 2020

As one's quality of life is greatly affected by our health status, the needs for more accurate, convenient diagnosis methods are growing. Various techniques and devices are being developed to distingush diseases as early as possible, especially regarding cancer. Here, of all types of cancer, we focus on bladder cancer and introduce technique to detect its potential biomarker, Apolipoprotein A1.

Bladder cancer, which is 6th most occuring cancer in men and known for quite high recurrent rates, has been diagnosed with gold-standard methods called cystoscopy and cytology. Although, cytoscopy that uses slim camera to look inside bladder, is a precise method, the process itself is invasive and time-consuming, thus gives pain to the patients, considering that it will be repeated for regular check up. Urine cytology, which could give less burdeon to the patient due to its non-invasive approach, however, shows less sensitivity to distinguish relatviely early-stage of bladder cancer.

To solve those limitations of exisiting techniques, detecting urine level of Apo-A1(Apoplipoprotein A1) present can be an effective alternative to distingusih bladder cancer patients with no painful process and accuracy. Apo-A1 is known to appear to patients with 3-fold higher concentrations than normal groups. Here, we developed a electrochemical biosensor platform for rapid detection of Apo-A1 using electrochemical impedance spectroscopy, one of sensitive electrochemical detection techniques, resulting that early diagonistics of patients without invasive techniques can be made possible. In our study, 0 – 1 nM (0, 0.01, 0.1, 1 nM) concentrations of Apo-A1 were succesfully detected with rising value of charge transfer resistance, which means that it showed possibility to be applied to patients with lower levels of Apo-A1.
Investigation of the Lifetime of Electrochemical Immunosensor Based on Immunochromatographic Strip for the Infectious Disease Testing
Authors: Truong Cuong Khac Phu , Han Dawoon , Lee Dong-Hoon
Published: December 2020

Lateral flow tests, also known as immunochromatographic assays, are the most popular technique for point-of-care detection. Combined with the advantages of electrochemical immunoassays, portability and quantitative requirements can be met. However, when the sensor’s reproducibility and mass production are of more importance for practical applications, antibody activity retention is the most critical factor. Once adsorbed to a solid surface, antibodies do not always retain the activity and performance during storage. Although some antibody stabilizers in solution such as sucrose, azide, can be used, their effects might be limited in novel conditions such as in electrochemical assays1. Therefore, finding additional methods for improving the long-term stability of antibodies is crucial for these novel devices. Blocking agents not only prevent non-specific binding but also stabilize the immobilized reactant by sterical support2. Herein, Bovine serum albumin (BSA), Polyvinylpyrrolidone (PVP), and Casein are investigated and optimized as blocking agents. 3% casein under 2 hours of treatment by homogenizer showed the lowest background and minimum loss of charge after 3 days of storage in less than 10% low humidity (-16% whereas PVP lost -55%). Their performance was corroborated by testing a Dengue virus electrochemical immunosensor with 3,3’,5,5’-Tetramethylbenzidine (TMB) as electrochemical reagent for horseradish peroxidase (HRP). A sandwich immunoreaction was performed on the immunochromatographic strip and the oxidized TMB was measured amperometrically with a screen-printed electrode, which is embedded close to the capture antibody area. As antibody systems derived from other assays such as ELISA do not maintain their reactivity in lateral flow tests and other alternatives prove to be limited, our strategy becomes a potential approach that can be applied in extensive combinations with other existing methods.

EMD Millipore. Rapid Lateral Flow Test Strips - Considerations for Product Development; EMD Millipore Corporation,
2013.

Jitsukawa, T.; Nakajima, S.; Sugawara, I.; Watanabe, H. Increased Coating Efficiency of Antigens and Preservation of Original Antigenic Structure after Coating in ELISA. Immunol. Methods
1989, 116 (2), 251–257.
Development of a Movable Membrane Probe for the Pretreatment of Target Analytes in the Electrochemistry Based Assay
Authors: Jin Enjian , Go Anna , Lee Min-Ho
Published: December 2020

In this paper, we electrochemistry based immunoassay system using newly developed movable membrane probe which we used as pretreatment before the measurement of target analytes. We used Alkaline phosphatase (ALP) as enzyme which is widely used for an enzyme in immuno-sensor due to its high stability of reaction, long storage life, and high turnover rates. [1] For the enzymatic hydrolysis and activity for electrochemistry, we used a substrate as p-aminophenyl phosphate (pAPP). In addition, we utilized co-enzyme, tris(2-carboxyethyl) phosphine (TCEP), for the enhanced measurement signal in the substrate for the amplification of relatively low signal in electrochemical measurement. [2] The developed moveable membrane probe provided a simple methodology regarding the conjugation of antibodies on surfaces and washing process compared to manually orchestrated normal ELISA. The main advantage of this system is the easiness of washing steps, we could produce lower background signal which eventually resulted in an increase of the signal to noise ratio. This membrane probe was designed to be implemented to the platform which was newly developed all in one electrochemisty based immunoassay platform names as IMPACT.

Using this base platform and movable probe, we could measure thyroid related hormones in successive ways even their presence in extremely low ranges.
Organic-Inorganic Hybrid Sol-Gel Materials for Optical Fiber Sensing Application
Authors: Figueira Rita Bacelar , Silva Carlos J. R.
Published: December 2020

The Integration of advanced sensing devices into concrete and reinforced concrete structures (RCS) is a rational approach for the assessment of repair options and scheduling of inspection and maintenance strategies. The imediate advantages are cost reduction and a more reliable prevention of unpredictable events. The use of optical fiber sensors (OFS) for such purposes has increased in the last few years due to their intrinsic advantages such as lightweight, corrosion resistance, immunity to electromagnetic interference and multiplexing capabilities. In most OFS, the chemical transducer consists of immobilized chemical reagents, placed in the sensing region of the optical sensor by direct deposition or by encapsulation in a polymeric matrix. The choice of the support matrix influences the performance of the sensor, which is governed by factors such as the permeability to the analyte, suitability for reagent immobilization and adequate optical response. In the last few years, OFS, cement-based strains and nanomaterial based sensors have been reported and implemented in diverse structures. It has been demonstrated that they could monitor several physical and chemical properties directly related to concrete and RCS durability. However, most of them show poor and inconsistent responses, signal drift due to dye leaching, reduced pot life and unsuitability to operate at pH > 12.

New organic-inorganic hybrid (OIH) sol-gel materials were obtained using a functionalized siloxane 3-Glycidoxypropyltrimethoxysilane (GPTMS) by the reaction with different oligopolymers (referred to as Jeffamine), namely Jeffamine® RFD 270, Jeffamine® THF 170 and Jeffamine® T403. The OIHs were doped with different silver nanoparticles contents and also with different contents of pH indicators (i.e. phenolphthalein and orange II) . These materials were developed for application on OFS to monitor the pH concrete and chloride ions. The chemical stability of these materials was studied in simulative concrete solutions (pH > 12.5) and in mortars by electrochemical impedance spectroscopy (EIS). The materials synthesized were characterized by UV–Visible spectrophotometry, EIS, fluorescence spectroscopy and Fourier-transform infrared spectroscopy. The produced OIH materials show promising properties to be coupled to advanced OFS to monitor pH and chloride ions in concrete. The real-time monitoring of these parameters will contribute to understand/antecipate the progress of RCS deterioration mechanisms. Furthermore, integrated systems will contribute for the development/improvement of theoretical models to predict with high accuracy the service life of concrete and RCS under the action of combined effects.
pH Micro-Sensor from IrOx SECM Microelectrode for Local pH Measurement While Chromium Electrodeposition
Authors: Dasque Ariane , Gressier Marie , Taberna Pierre-Louis , Menu Marie-Joelle
Published: December 2020

In this work, it will be presented the chromium electrodeposition mechanisms with the use of a Scanning ElectroChemical Microscopy (SECM) micro-electrode. Among several factors, the pH is key to achieve even a metallic deposit. pH buffers and complexing agents are often used for this purpose [1] but in the vicinity of the electrode, at the electrode/electrolyte interface, strong variations are highly likely to occur. To this respect, since pH is a key parameter, a pH micro-electrode is intended to be developed to scan the pH gradient upon the electrodeposition of chromium. The first part of this work is so devoted to the pH micro-electrode realization from microelectrode on which iridium oxide is deposited. Iridium oxide has been reported to be suitable for local pH sensing [2-4]. Different parameters have been studied such as IrOx thickness and thermal treatment. The addition of Nafion has been assessed as well to achieve a tradeoff between fast response time, good selectivity and good stability [5]. An optimized IrOx micro-electrode has been obtained and used as SECM micro-electrode to get the evolution of the pH at the electrode/electrolyte interface upon electrodeposition. Different micro-electrode diameters have been used to improve the resolution. These results are promising and will allow going further to the development of chromium electrodeposition electrolyte helping to select the different complexing agents.

[1] D. Del Pianta et al. Determination of the chromium(III) reduction mechanism during chromium electroplating. Electrochimica Acta (2018) 234-241.

[2] H. A. Elsen et al. Effects of electrodeposition conditions and protocol on the properties of iridium oxide pH sensors electrodes. J. Electrochem Soc. 156 (2009).

[3] C. S. Santos et al. Fabrication and use od dual-function iridium oxide coated gold SECM tips. An application to pH monitoring above copper electrode surface during nitrate reduction. Electroanalysis 28 (2016) 1441-1447.

[4] Z. Zhu et al. A fabrication of iridium oxide film pH micro-sensor on Pt ultramicroelectrode and its application on in-situ pH distribution of 316 stainless steel corrosion at open circuit potential. Sensors and Actuators B 25 (2018) 1974-1982.
Nanosensor Array Platform to Capture Whole Disease Fingerprints
Authors: Kim Mijin , Yang Yoona , Wang Peng , Chen Chen , Antman-Passig Merav , Luo Hongbin , Zheng Ming , Wang YuHuang , Jagota Anand , Heller Daniel A.
Published: December 2020

Organic color centers (OCC) are synthetic color-centers that are incorporated in single-wall carbon nanotubes by covalently attaching functional groups to the otherwise crystalline semiconductors. OCCs feature extraordinary traits that make these synthetic materials an ideal platform for the biochemical sensing applications. First, the OCC-induced fluorescence peak is extremely sensitive to the local microenvironment around the functional group that induced each OCC. Second, OCCs are molecularly tunable. Depending on the chemical nature of the functional group that induces each OCC, the fluorescence features can be systematically controlled. Based on the extraordinary chemical tunability and sensitivity of OCCs, we construct a perception-based sensing array that enables multiplexed sensing of disease biomarkers in biofluids. The sensing array consists of systematically designed OCC-receptor elements that non-specifically interact with a myriad of molecular species in biofluid. The diverse spectral responses of the sensor array, trained by machine learning, collectively determine the disease fingerprints.
Welcome Remarks - M02: Chemical Sensors 13: Recent Advances in Chemical and Biological Sensors and Analytical Systems
Authors: Shimizu Yasuhiro
Published: December 2020

Welcome to M02: Chemical Sensors 13: Recent Advances in Chemical and Biological Sensors and Analytical Systems! Take a moment to listen to welcome remarks from the lead organizer, Yasuhiro Shimizu.
(Invited) Polymer Functionalized Nanocarbons for Biomedical Applications
Authors: Budhathoki-Uprety Januka , Chen Yu , Drago Julia , Godthi Nidhi , Sultana Nigar
Published: December 2020

Nanocarbons such as photoluminescent single-walled carbon nanotubes are promising materials in biomedical field as molecular imaging agents, optical probes, and biosensors. These carbon-only nanomaterials lack active surface functional moieties to interact effectively with select biomolecules of interest, which limits their potential applications. Tailored surface functionalization is essential for anticipated functions and bio-compatibility. Polymer adsorption on nanocarbons through multivalent interactions provides a versatile platform to develop functional materials with tunable surface chemistry. Herein, we investigate on biomimetic polymer scaffolds for carbon nanotubes to modulate their physiochemical properties and bio-molecular interactions.
In Vivo Biocompatibility of Single Walled Carbon Nanotubes
Authors: Yaari Zvi A , Yang Yoona , Jagota Anand , Zheng Ming , Heller Daniel A.
Published: December 2020

Ovarian cancer patient prognosis and quality of life are significantly affected by the failure to accurately diagnose disease at early stage. Currently, less than 15% of ovarian cancer patients are diagnosed at stage 1, when 5-year survival rates are near 93%. Early detection may save more than 80% of women diagnosed with ovarian cancer. Our goal is to develop clinical long-term implantable carbon nanotube-based sensors for ovarian cancer biomarkers to transiently detect and monitor their levels in patients. The proposed sensors will harness the unique optical properties and sensitivity of single-walled carbon nanotubes. To improve sensitivity and specificity of such sensors, previously developed to detect ovarian cancer biomarkers in vivo, we used molecular perceptron—data analytics-based methods to detect specific spectroscopic fingerprints from the binding of protein biomarkers to the nanotube surface.
(Invited) In Vivo Analyte Detection Via Single-Walled Carbon Nanotube Near-Infrared Fluorescence
Authors: Williams Ryan M. , Harvey Jackson , Galassi Thomas , Heller Daniel A.
Published: December 2020

Implantable optical nanosensors hold the promise of rapid, minimally-invasive longitudal monitoring of analytes in a patient or animal. Such devices will allow for informed clinical intervention based on changes in drug, biomarker, or disease state profiles. We developed implantable nanosensors based on the optical properties of single-walled carbon nanotubes (SWCNT). SWCNT fluorescence is in the ‘tissue-transparent’ near-infrared spectrum, allowing for fluorescence measurements after implantation inside an animal. Further, SWCNT fluorescence is photostable, allowing for multiple measurements over time. We engineered separate SWCNT-based sensors such that their fluorescence emission responded to various analytes, including small molecule drugs as well as protein and nucleic acid biomarkers. Each sensor device was immobilized into a semi-permeable biocompatible membrane, allowing analyte penetration but retaining SWCNT inside. We implanted each sensor device into live mice, either in the peritoneal cavity or subcutaneously, and performed whole-mouse near-infrared fluorescence imaging to ensure the stability of the membrane and sensor brightness. We used a sensor implant specific for the chemotherapeutic doxorubicin to drug monitor transport within the animal. We used sensor implants specific for the ovarian cancer protein biomarker HE4 or for individual microRNA sequences to measure exogenous or cancer-generated quantities of each biomarker in mice. We expect these implantable sensors to have potential as research tools or clinical diagnostics to monitor pharmacokinetics or locally measure disease biomarkers in real-time.
(Invited) Near Infrared Nanosensors to Image Brain Neurochemistry
Authors: Landry Markita P
Published: December 2020

Neurons communicate through chemical neurotransmitter signals that either terminate at the postsynaptic process (“wired transmission”) or diffuse beyond the synaptic cleft to modulate the activity of larger neuronal networks (“volume transmission”). Molecules such as dopamine belong to the latter class of neurotransmitters, and have been the pharmacological targets of antidepressants and antipsychotics for decades. Owing to the central role of dopamine over a range of behaviors and psychiatric disorders, real-time imaging of the signal’s spatial propagation would constitute a valuable advance in neurochemical imaging. To this end, we present a nanoscale near-infrared fluorescent nanosensor for dopamine and demonstrate its efficacy for imaging dopamine volume transmission in the extracellular space of the brain striatum and prefrontal cortex (Beyene et al. ACS Chem. Neuro. 2017). The sensor is developed from polymers pinned to the surface of single wall carbon nanotubes (SWNT) in which the surface-adsorbed polymer is the recognition moiety and the carbon nanotube the fluorescence transduction element. Excitonic transitions in functionalized SWNT yield up to ΔF/F = 4500% near-infrared fluorescence emission in the presence of dopamine (Beyene et al. Nano Letters 2018). We next demonstrate imaging of evoked dopamine release in acute striatal slices, and show altered dopamine reuptake kinetics when brain tissue is exposed to dopamine receptor agonist and antagonist drugs (Beyene et al. Science Advances 2019). Lastly, we discuss how to evolve synthetic molecular recognition for other neuromodulators of interest, such as serotonin (Jeong et al. Science Advances 2019). We characterize our findings in the context of their utility for high spatial and temporal neuromodulator imaging in the brain, describe nanosensor exciton behavior from a molecular dynamics (MD) perspective, and validate nanosensor for use to elucidate dopaminergic signaling variability with disease or pharmacological perturbations at a synaptic scale.
(Invited) High-Frequency Drug and Metabolite Measurements in Situ in the Living Body Via Electrochemical Aptamer-Based Sensors
Authors: Plaxco Kevin W
Published: December 2020

The availability of technologies capable of tracking the levels of drugs, metabolites, and biomarkers in real time in the living body would revolutionize our understanding of health and our ability to detect and treat disease. Imagine, for example, a dosing regime that, rather than relying on your watch (“take two pills twice a day”), is instead guided by second-to-second measurements of plasma drug levels wirelessly communicated to your smartphone. Such a technology would likewise provide researchers and clinicians an unprecedented window into neurology and physiology, and could even support ultra-high-precision personalized medicine in which drug dosing is optimized minute-by-minute using closed-loop feedback control. Towards this goal, we have developed a biomimetic,electrochemical sensing platform that supports the high frequency, real-time measurement of specific molecules (irrespective of their chemical reactivity) in situ in the blood and tissues of awake, freely moving subjects.
Ultrasound-Responsive Nanoparticles for Continuous pH Sensing In Vivo
Authors: Walker Julia , Kempe Kristian , Corrie Simon
Published: December 2020

Ultrasound (US) is one of the most commonly used medical imaging techniques. Contrast agents are administered to patients to improve fidelity of US images and for theranostic applications. The majority of current research into US contrast agents relies on microbubbles containing a phospholipid shell surrounding a gaseous core, as this leads to high degree of echogenicity. However, these materials only last for 5-30 minutes in vivo due to diffusion of the gas into the bloodstream. To our knowledge, the combination of ultrasound technology and contrast agents to create in vivo biosensors has not yet been investigated. In this work we designed and produced a pH-sensitive US contrast agent based on core-shell materials. Here we used a silica scaffold coated with Layer-by-Layer (LbL) polymer as the dynamic component (Figure 1). We found that following encapsulation of the hybrid particle in a silica shell, pH changes induced polymer rigidity changes which could be detected using standard clinical and pre-clinical ultrasound imaging systems. Herein we will describe the material design and characterisation, gel phantom ultrasound studies, and real-time in vivo biosensing of pH in the live animal. Such biosensors could find application in biomedical research and clinical diagnostics in deep tissue, providing real-time information without relying on laboratory infrastructure or complex imaging systems.
(Invited) Deployable Biosensing Devices for Monitoring of Cytokines In Vivo
Authors: Liu Guozhen
Published: December 2020

Cytokines, low molecular weight (~6-70 kDa) soluble proteins secreted from the immune and non-immune cells are core indicators of the functional status of the body, and strongly associated with the immune system. Cytokines secreted from cells play critical roles in tissue repair, cancer development and progression. Monitoring cell-to-cell communication through cytokine secretions has enormous value in biology and medicine. Unfortunately, probing what cells “see”, and what they secrete locally as they respond in real time to the surrounding signals is still a major challenge. The ultra-low concentration of cytokine (in the pM range), and extremely dynamic, transient cytokine secretion process make cytokine quantification even difficult. Recently we have developed both fluorescence and electrochemical biosensors for sensitive detection of cytokine in vitro and in vivo with the pg/mL sensitivity. This talk will summarize our recent research highlights on development of deployable biosensing devices for detection of single and multiple cytokines in vivo such as mice brain or spinal cord.