bluuebunny/crossref_metadata_2025_split huggingface dataset:
Melanin-Based Thin Films for Sustainable Electronic Devices
Authors: Saini Pooja , Santato Clara 
Published: May 2020

Melanin is a natural (bio-sourced) and bio compatible material, attracting attention because of its physicochemical properties. Melanin is a family of pigments and the brown-black eumelanin pigment is part of this. It can be found in skin, hair, eyes, and brain [1-2]. Considering its quinone-based and conjugated molecular structure, eumelanin is an interesting candidate for bioelectronics. Transport physics in eumelanin-based thin films and pellets need to be better understood to optimize its technological applications. The main challenge for the use of eumelanin in bioelectronics is to increase the conductivity and detailed study is required to clarify and quantify the electronic and protonic contribution to charge transport.
High quality thin films of eumelanin material on substrates such as ITO (Indium Tin Oxide) and FTO (Fluorine Tin Oxide) substrates were prepared to study the electronic transport properties of the biopigment. The electrodeposition method, spray pyrolysis, and spin coating were used for the preparation of uniform thin films. The structural, optical, and morphological properties of these thin films were studied using X-ray diffraction (XRD), atomic force microscopy (AFM), field emission electron microscopy (FESEM) and transmission electron microscopy (TEM). For the metal contacts both top contacts using a through shadow masking and photolithography were used. Preliminary results on the dependence of electronic transport on temperature, relative humidity, and interelectrode distance range were collected.
Reference
[1] Julia Wunsche, Yingxin Deng, Prajwal Kumar, Eduardo Di Mauro, Erik Josberger, Jonathan Sayago, Alessandro Pezzella, Francesca Soavi, Fabio Cicoira, Marco Rolandi, and Clara Santato, Chem. Mater. 2015,27, 436−442.
[2] Prajwal Kumar, Eduardo Di Mauro, Shiming Zhang, Alessandro Pezzella, Francesca Soavi, Clara Santato and Fabio Cicoira, J. Mater. Chem. C, 2016, 4, 9516.
(Invited) Detection of Cancer Biomarkers By Scanning Electrochemical Microscopy
Authors: Lin Tzu-En , Darvishi Sorour , Lesch Andreas , Girault Hubert H. 
Published: May 2020

Scanning electrochemical microscopy (SECM) is a scanning probe technique that is composed of a micro- or nanoelectrode that can be scanned in close proximity to an interface. Faradaic current signals can be recorded due to the flux of redox active species between the sample and an amperometric SECM probe. SECM can be used to image the topography and reactivity of biological specimens for mapping localized biochemical activity. Although SECM has been applied to different biological systems, SECM studies of tissues are still under exploration. The reason is due to the shape and high roughness of such real samples and requires overcoming major drawbacks in conventional SECM instrumentation when scanning large, i.e. square centimeter sized, areas with irregular surface keeping a constant working distance.
My research aims to develop various reliable SECM bioimaging techniques for the study of the distribution of biomarkers in tape-stripping cancer samples and human melanoma tumor samples. Melanoma is the most lethal form of skin cancer striking thousands of people around the world. The survival rate depends on the stage of the cancer when it is diagnosed. SECM could improve the diagnosis and understanding of different melanoma stages based on highly resolved maps of the tyrosinase distribution in tumor sections. [1]
Furthermore, the increasing levels of tyrosinase were recorded in cells that were collected from the skin of melanoma mouse models representing three different stages of tumor growth. [2] Additionally, SECM results of tape-stripped different human melanoma cell lines were confirmed by previous studies based on traditionally fixed and permeabilized cells. The presented electrochemical tyrosinase detection approach can potentially be integrated into point of-care testing (POCT) devices. SECM scanning parameters, such as microelectrode size and step size can be used to determine experimentally the best design before fabricating microelectrode array prototypes. [1]
1. Lin TE, Lu YJ, Sun CL, Pick H, Chen JP, Lesch A, Girault H. Soft electrochemical probes for mapping the distribution of biomarkers and injected nanomaterials in animal and human tissues Angew. Chem. Int. Ed. 2017;56:16498–16502.
2. Darvishi S, Pick H, Lin TE, Zhu Y, Li X, Ho PC, Girault HG, Lesch A. Tape-Stripping Electrochemical Detection of Melanoma Anal. Chem. 2019, 91, 12900–12908
Detection of Volatile Organic Compounds in Contaminated Air Using Gas Sensors with Machine Learning
Authors: Shin Woosuck , Itoh Toshio , Koyama Yutaro , Akamatsu Takafumi , Tsuruta Akihiro , Masuda Yoshitake , Uchiyama Kazuhisa 
Published: May 2020

We investigate selective detection of target volatile organic compounds (VOCs) as unpleasant odor substances in the presence of interference VOCs from car interiors. We selected four unpleasant odor substances as target gases, such as age-related body odors and fungi, and two interference VOC substances, such as the main olfactory components from car interiors, in this study. We used eight semiconductive gas sensors including six general semiconductive gas sensors and two bulk-response type semiconductive gas sensors. Discrimination of each target gases was carried out using machine learnings, such as principal component analysis (PCA) and linear discriminant analysis (LDA), which are dimensionality reduction methods. PCA is an unsupervised learning method, and finds the axis that maximizes the data’s variance. LDA is a supervised learning method, and finds maximizes the separation between multiple classes. The machine learnings used sensor responses (r=Ra/Rg; r: sensor responses, Ra: resistance in humid pure air or in contaminant, Rg: resistance in the target gases) from all sensors.
The plots of PCA scores tended to move radially outward as concentrations of target gases increased. PCA scores of target gases with contaminants showed almost the same as those of lower concentration target gases without contaminants. However, the PCA scores in the presence of contaminants were within the area of each target gas so that the discrimination between the target gases was almost achieved. The LDA scores were classified by target gases without concentrations of target gas and contamination, so the LDA scores tended to aggregate with target gases. The plots of LDA scores seemed to be more gathered in each class (target gas) area than those of PCA scores.
Moreover, we investigated to reduce the number of sensors using another machine learning, i.e. feature selection technique, which used the sensor responses for obtaining sensor weights against all data. Based on the results of another machine learning, we selected three sensors which possess high scores in another machine learning. The PCA and LDA scores from selected three sensors showed almost the same qualities as those from eight sensors, whereas those from non-selected sensors cannot discriminate target gases, so the amount of information of the target gases has been reduced by excluding the selected three sensors for separating each target gas. From this result, it is possible to reduce the number of sensors to keep the discrimination between target gas by selecting sensors obtained using feature selection techniques.
Fig. PCA scores and eigenvectors from eight sensors to four target gases.

Figure 1
Porous Enzymatic Membrane for Nanotextured Glucose Sweat Sensors with High Stability Towards Reliable Noninvasive Health Monitoring
Authors: Lin Yuanjing , Zhao Jiangqi , Fan Zhiyong , Javey Ali 
Published: May 2020

Development of reliable glucose sensors for noninvasive monitoring without interruption or limiting users’ mobility is highly desirable, especially for diabetes diagnostic which requires routine/long term monitoring. However, their applications are largely limited by the relatively poor stability. Herein, a porous membrane is synthesized for effective enzymes immobilization and it is robustly anchored to the modified nanotextured electrode solid contacts, so as to realize glucose sensors with significantly enhanced sensing stability and mechanical robustness. To the best of our knowledge, it is the first report on utilizing such nanoporous membranes for electrochemical sensor applications, which eliminates enzymes escaping and provides sufficient surface area for molecular/ion diffusion and interactions, thus to ensure the sustainable catalytic activities of the sensors and generate reliable measureable signals during noninvasive monitoring. The as-assembled nanostructured glucose sensors demonstrates reliable long-term stable monitoring with minimal response drift for up to 20 hours, which delivered a remarkable enhancement. Moreover, they can be integrated into a microfluidic sensing patch for noninvasive sweat glucose monitoring. The as-synthesized nanostructured glucose sensors with remarkable stability can inspire developments of various enzymatic biosensors for reliable noninvasive composition analysis.
Besides, in order to realize the ultimate applications of these sensors in predictive clinical diagnostics, personalized healthcare monitoring and chronic diseases management, a self-powered and fully integrated smartwatch in a “smartwatch” fashion was demonstrated. It consists of flexible photovoltaic cells and rechargeable batteries in form of a “watch strap”, electrochemical glucose sensors, customized circuits and display units integrated into a “dial” platform, is successfully fabricated for real-time and continuously monitoring of sweat glucose levels. The functionality of the smartwatch, including sweat glucose sensing, signal processing and display, can be supported with the harvested/converted solar energy without external charging devices. The Zn-MnO2 batteries serve as intermediate energy storage units and the utilization of aqueous electrolytes eliminated safety concerns for batteries, which is critical for wearable devices. Such a wearable smartwatch realizes integration of energy modules with self-powered capability, electrochemical sensors for noninvasive glucose monitoring, in situ and real-time signals processing/display in a single platform for the first time. The as-fabricated fully integrated and self-powered smartwatch also provides a promising protocol for statistical study and clinical investigation to reveal correlations between sweat compositions and human body dynamics.
Nanomaterial-Based Electrochemical Sensor for the Detection of Hydroxyproline
Authors: Durairaj Sharmila , Sidhureddy Boopathi , Chen Aicheng 
Published: May 2020

The physicochemical properties of gold has attracted tremendous research in various fields such as sensing, drug delivery and bio-catalysis. Gold nanoparticles exhibit splendid electron transfer properties, high surface area, good conductivity and increased biocompatibility. Gold-based nanomaterials exhibit high-performance for the detection of biomolecules such as amino acids, proteins and microbes [1]. Hydroxyproline (HYP) is a major amino acid present in connective tissues and extracellular matrix in all animals cells. L-hydroxyproline (L-HYP) is one of the major imino acid present in the connective tissue proteins such as collagen. L-HYP acts as a biomarker in various diseases connected to collagen such as wound healing, idiopathic pulmonary fibrosis, and necrosis. Quantitative analysis of L-HYP level in the body fluids helps in disease diagnosis and early treatment. Here, we report on a facile electrochemical sensor based on gold nanoparticles for the detection of L-HYP using cyclic voltammetry and differential pulse voltammetry. The performance of the fabricated electrochemical sensor was further testeduisng Achilles tendon collagen and human urine samples. The optimized electrochemical sensor exhibits high sensitivity and selectivity.
[1] M. Govindhan, M. Amiri, A. Chen. Biosens. Bioelectron. 66 (2015) 474–480.
(Invited) Exploring in the Near Infrared: Multifunctional Nanoplatforms for Biomedical Applications
Authors: Ma Dongling 
Published: May 2020

Near-infrared (NIR) absorbing and emitting nanomaterials attract significant attention in bioimaging, which shows great potential for disease detection due to its high sensitivity at the subcellular level and low cost of related imaging facilities. However, currently available optical probes are mainly based on visible-emitting materials. The tissue-induced optical extinction and autofluorescence in the visible range result in limited penetration depth and ambiguous photoluminescence signal, which restricts their in vivo use. To address this issue, photoluminescent probes, with both absorption and emission wavelengths operating in the biological windows in the NIR range, in which tissues are optically transparent, are highly desired. Their integration with superparamagnetic nanomaterials to make a multifunctional platform further opens a wide range of promising applications, including bimodal imaging (photoluminescence and magnetic resonance imaging), synergistic hyperthermia (magnetothermal and photothermal), magnetic confinement of trace amounts of biospecies for ultra high-sensitivity biodetection, etc. In this talk, I will present our most recent work on the synthesis of NIR-emitting water soluble, stable core/shell/shell quantum dots (QDs) and multifunctional (NIR photoluminescent and superparamagnetic) nanoparticles and their use in biomedicine. For instance, in one case, multifunctional particles contain single superparamagnetic nanoparticles as cores and NIR-luminescent nanomaterials as shells. In another case, the multifunctional nanoplatform is compose of multiple superparamagnetic nanoparticles and NIR quantum dots in single particles. These different types of multifunctional particles are designed for different biomedical applications.
References: [1] ACS Nano 2019, 13, 408-420; [2] Adv. Funct. Mater. 2018, 1706235 (Inside Back Cover); [3] Chem. Mater. 2019, 31, 3201-3210.
(Invited) Blood, Sweat and Tears... – Sensing of Human Performance Biomarkers in Bodily Fluids Using Point-of-Use Devices
Authors: Steckl Andrew 
Published: May 2020

Hormones produced by glands in the endocrine system and neurotransmitters produced by the nervous system control many bodily functions. The concentrations of these molecules in the body are an indication of its state, hence the use of the term biomarker. Excess concentrations of biomarkers, such as cortisol, serotonin, epinephrine, dopamine, are released by the body in response to a variety of conditions - emotional state (euphoria, stress), disease, etc. The development of simple, low-cost modalities for point-of-use (PoU) measurements of biomarkers levels in various bodily fluids (blood, urine, sweat, saliva) as opposed to conventional hospital or lab settings is receiving increasing attention. The presentation starts with a review of the basic properties of primary stress-related biomarkers: origin in the body (i.e. if they are produced as hormones, neurotransmitters or both), chemical composition, molecular weight (small/medium size molecules and polymers, ranging from ~100Da to ~100kDa), hydro- or lipo-philic nature. Next, a review of the published literature is presented regarding the concentration of these biomarkers found in several bodily fluids that can serve as the medium for determination of the condition of the subject: blood, urine, saliva, sweat and, to a lesser degree, interstitial tissue fluid. The concentration of various biomarkers in most fluids covers a range of 5-6 orders of magnitude, from 100s of ng/mL (~1µM) down to a few pg/mL (sub 1pM). Mechanisms and materials for point-of-use biomarker sensors are summarized and key properties are reviewed. Illustrative examples from the literature are discussed for several sensor device categories, including lateral flow (immuno)assay devices and microfluidic devices. Selected methods for detecting these biomarkers are reviewed, including antibody- and aptamer-based colorimetric assays, electrochemical and optical detection. Finally, the presentation outlines key challenges of the field and provides a look ahead to future prospects.
A.J. Steckl and P. Ray, “A Review of Stress Biomarkers Concentrations in Bodily Fluids and Their Point-of-Use Detection”, ACS Sensors, 3 (10), 2025-2044, Sept 2018 (10.1021/acssensors.8b00726).
V. Venkatraman and A.J. Steckl, “Quantitative Detection in Lateral Flow Immunoassay using Integrated Organic Optoelectronics”, IEEE Sensors, 17 (24), 8343, Dec 2017 (10.1109/JSEN.2017.2764178 ).
P. Ray and A.J. Steckl, “Label-Free Optical Detection of Multiple Stress Biomarkers in Sweat, Plasma, Urine and Saliva”, ACS Sensors
4, 2019. (10.1021/acssensors.9b00301)
S. Dalirirad and A.J. Steckl, “Aptamer-Based Lateral Flow Assay for Point of Care Cortisol Detection in Sweat”, Sensors & Actuators
283, 79-86, Jan 2019 (https://doi.org/10.1016/j.snb.2018.11.161).

Figure 1
(Invited) Theranostics with Lanthanide Doped Nanoparticles
Authors: Vetrone Fiorenzo 
Published: May 2020

In recent years, a significant amount of research has focused on nanoparticle-based “theranostic” agents for the treatment of a wide array of diseases, including cancer. This new paradigm in personalized medicine intends to exploit nanoplatforms that carry both therapeutic and diagnostic (theranostic) modalities. Compared with delivering drugs or imaging agents separately, theranostic agents can simultaneously deliver them to specific sites, enabling detection and treatment of disease in a single procedure. Many theranostic nanoplatforms are triggered by light, however, the vast majority of these are limited in that the ultraviolet or visible excitation light used has minmal applicability in biological applications. Lanthanide doped nanoparticles, on the other can be excited with biologically friendly near-infrared light (in the biological windows) and can emit in the ultraviolet, visible or near-infrared regions through a multiphoton upconversion process while simultaneously emitting in the near-infrared region through a Stokes or downshifted process. Hence, the upconversion luminescence can be used to trigger the therapeutic application (drug delivery, photodynamic therapy, etc.) while the near-infrared luminescence can be used for the diagnostic modality (bioimaging, nanothermometry, etc).
In this presentation, we will introduce lanthanide doped nanoparticles and demonstrate their usefulness in theranostics. In particular, we will show complex nanoparticle architectures can endow further functionality to these nanoparticles including the ability to decouple the theranostic processes that are conventionally delivered simultaneously.
(Invited) Electrochemical Detection of Gases and Explosives in Ionic Liquids in Different Humidity Environments
Authors: Silvester Debbie S. , Lee Junqiao , Doblinger Simon , Hay Catherine 
Published: May 2020

Amperometric gas sensors (AGSs) are widely used due to their many advantages, such as low-cost, portability, durability, wide linear range, high sensitivity and high selectivity [1]. They are available commercially from a number of companies [2], and can detect a range of redox-active gases. The sensor devices typically employ a water/sulfuric acid mixture as the electrolyte in contact with three electrodes, covered by a gas-permeable membrane. Room temperature ionic liquids (RTILs) have strong potential for use as alternative ‘designer solvents’ in membrane-free AGSs [3], which would solve the existing technological problems of commercial AGSs, including the slow diffusion through the membrane and solvent evaporation. Their non-volatility would enable the membrane to be dispensed with, and the entire sensor to be miniaturised to provide optimal functionality over a much wider range of ambient conditions and with a longer lifespan. This allows and encourages innovative designs, with the potential for gas sensors to move from single, finite devices to more sophisticated systems that exploit recent advances in portable electronics and computing.
In this talk, I will discuss some of the challenges facing ionic-liquid based sensors, such as solvent leakage, sensitivity to moisture and accumulation of electrogenerated products, and how we can innovatively design electrode materials and electrolytes to overcome these challenges. In particular, I will show that the choice of ionic liquid is crucial in high humidity gas environments, due to the structuring and layering of the ions in the electrical double layer [4]. I will also discuss the possibility to detect explosive compounds in RTILs, and polymer-RTIL mixtures [5]. Overall, it is clear that RTILs show tremendous promise as electrolytes in sensors, but more understanding of their long-term operation and utility in real environments is still needed.

References

[1] Stetter JR, Li J, Amperometric Gas Sensors – A Review Chem. Rev.
2008, 108, 352–366.
[2] Xiong L, Compton RG, Amperometric Gas detection: A Review Int. J. Electrochem. Sci., 2014, 9, 7152–7181
[3] Buzzeo MC, Hardacre C, Compton RG Anal. Chem. 2004, 76, 4583–4588.
[4] Doblinger S, Lee J, Silvester DS J. Phys. Chem. C
2019, 123, 10727−10737.
[5] Yu H, Lee J, Lewis SW, Silvester DS Anal. Chem.
2017, 89, 4729–4736.

Figure 1
pH Micro-Sensor from Modified Pt SECM Microelectrode for Local pH Measurement While Chromium Electrodeposition
Authors: Dasque Ariane , Gressier Marie , Taberna Pierre-Louis , Menu Marie-Joelle 
Published: May 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 a platinum 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.
[5] I. G. Borislav et al. Thin-film IrOx pH microelectrode for microfluidic-based microsystems. Biosensors and Bioelectronics 21 (2005) 248-256.