bluuebunny/crossref_metadata_2025 huggingface dataset:
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
Electrochemical Sensors for Detecting and Diagnosing Oral Diseases
Authors: Ritzert Nicole L. , Kim Shinae , Rani Asha , Moffat Thomas P.
Published: May 2020

Quantitative measurements of (non)specific biomarkers in the mouth could help clinicians to diagnose more accurately oral diseases (e.g., dental caries, periodontal disease, oral cancer) and implant failure as well as help researchers better understand how oral tissues interact with treatments and restorations. Our goal is to make electrochemical sensors for measuring target analytes in oral fluids (e.g., saliva) and tissues (e.g., dental pulp, gingiva). In this work, we developed pH sensors to aid in detecting inflammation and disease in the oral cavity. Miniaturized, planar pH sensing and reference electrodes were combined on a silicon wafer or flexible polymer platform using a combination of microfabrication and electrodeposition techniques. The voltage of the sensor was measured in solutions of varying pH, chloride concentration, and temperature mimicking the oral environment. In addition, sensors were characterized with optical microscopy, scanning electron microscopy (SEM), and profilometry. At room temperature (21-22 °C), the voltage between the pH sensing and reference electrodes exhibited a linear response for pH 2-10 and stabilized within 10-120 s at each pH value. Repetitions of a well-behaving sensor at one pH value were <±5 mV (≈0.1 pH). The change in voltage with changing pH was more at 37 °C than at 21°C. Thus, pH sensitivity of the sensors is linear for range of expected oral pH values. However, the response time will need be decreased for clinical applications, and the voltage will need to be calibrated based on temperature.
Development of a Multifunctional Electrochemical Probe for Detection of Anticoagulants in Whole Blood
Authors: Shi Yuesong , Sirbuly Donald
Published: May 2020

The ability to rapidly and accurately monitor anticoagulant drugs such as heparin is critical for cardiac surgical patients. Unfortunately, this is quite challenging due to the narrow therapeutic window and heterogenous molecular weight of heparin; which has led to heparin being the second most common ICU medication error. Currently the most widely used method to monitor heparin is the activated partial thromboplastin time (aPTT), however, this is an indirect measurement of heparin dose and requires blood sampling with long turnaround times. Here we develop a minimally invasive, multifunctional electro-optical fiber optic for the detection of heparin. These probes have a local optical channel for in situ optical spectroscopy and electrical channel for quantitative electrochemical sensing. To enhance the electrochemical surface area of the fiber optic, and provide a porous medium for ion transport and support matrix for the immobilization of heparin-complexing dyes, highly conductive polymer layers were developed that can be electrochemically deposited on the probes. Strong cathodic current changes, and attenuation of light through the medium are observed in heparin-spiked buffer solutions when heparin complexes with the dye molecules, and the degree of change can be correlated to heparin concentration. Electrical sensing were also carried out in human whole blood and used to extract heparin concentrations in real time. Given the small footprint of the electro-optic fiber optic probes, they can be inserted through an intravenous catheter to provide a novel in situ solution to rapid, quantitative monitoring of heparin dose in the bloodstream.
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.
(Invited) Modulate the Surface of Microelectrode for In Vivo Analysis
Authors: Zhang Meining
Published: May 2020

Physiological and pathological processes in the central nervous system (CNS) are basically encoded by neuromodulators, neurotransmitters and other kinds of neurochemicals among neurons. However, the chemical complexity of the cerebral environment largely necessitates a capability of the method to measure neurochemicals accurately. Over the past decade, we have been dedicating to develop strategies to in vivo detecting neurochemcial selectively and accurately. In order to differentiate the neurochemicals of interest from others in the CNS, we develop a new kind of microelectrode for in vivo monitoring of H2O2, which is prepared by, first, electrodeposition of Prussian blue (PB) onto carbon nanotube (CNT) assembled carbon fiber microelectrodes (CFEs) and then overcoating of the CFEs with a thin membrane of polydopamine (PDA) through self-polymerization. On the other hand, towards the goal of minimizing the protein adsorption on the brain-implanted microelectrodes, we found that pre-treatment of carbon fiber microelectrode (CFEs) with bovine serum albumin (BSA) can minimize further adsorption of proteins when the electrodes are implanted into the rat brain. We demonstrate that electrode precalibration in aCSF containing BSA is valid and effective for in vivo measurements. However, this also causes significant sensitivity drop of CFEs to neurochemicals, including DA. To in vivo tracking of neurochemical dynamics without decrease of electrode performance, we report an ultrathin cell-membrane-mimic film of ethylenedioxythiophene tailored with zwitterionic phosphorylcholine (EDOT- PC) electropolymerized onto the surface of a carbon fiber microelectrode (CFE), which not only resists protein adsorption but also maintains the sensitivity and time response for in vivo monitoring of dopamine (DA). As a consequence, the as- prepared PEDOT-PC/CFEs could be used as a new reliable platform for tracking DA in vivo and would help understand the physiological and pathological functions of DA
(Invited) Enzyme-Based Electrochemical Microbiosensors for In Vivo and in Vitro Monitoring of Neurotransmitters during Hypoxia
Authors: Andreescu Silvana
Published: May 2020

Measurements of neurotransmitter concentrations in blood and tissues are of great physiological and pathological importance and could be useful for monitoring and understanding the state and progress of a variety of neurological diseases. Electrochemical microbiosensors can provide real-time measurements of neurotransmitters, but sensors that function reliably and maintain accuracy in hypoxic environments are limited. This presentation will describe an enzyme-based electrochemical sensing technology that enables real time monitoring of key analytes associated with neural signaling and function during ischemia and high frequency stimulation. To design our sensors we utilize unique redox, catalytic and oxygen storage/release properties of ceria nanoparticles, originating from their dual oxidation state and the highly mobile lattice oxygen present at their surface. The construction and analytical performance of several enzyme sensors based on these nanoparticles will be discussed, along with results demonstrating their capabilities for monitoring of neurological activity (dopamine, lactate, glutamate) during hypoxia in brain slices and in intact awake animals, with high sensitivity, wide linear range, and low oxygen dependence. The results demonstrate promising characteristics of ceria nanoparticles as a biosensor material for in vivo monitoring of oxidase enzyme substrates, particularly in settings where the availability of oxygen may be limiting. The use of these materials opens new avenues for application of this technology in different fields such as biosensors, biofuel cells, point-of-care testing and implantable diagnostic devices.
In Vivo Assessment of Neurotransmitter Biomarkers in Live Zebrafish (Danio rerio) Embryos
Authors: Deshpande Aaditya Sunil , Dumitrescu Eduard , Orr Cassandra , Wallace Kenneth , Andreescu Silvana
Published: May 2020

Neurotransmitters control various biological pathways in the body. Serotonin, mood elevating molecule, is a well-known species which serves as a neurotransmitter controlling gastrointestinal tract movement. Nitric Oxide (NO) is involved in neurotransmission processes and it is as well as biomarker of oxidative stress. Detection of neurotransmitters in live biological samples remains a challenge due to their low concentration, short life and high reactivity. Electrochemical biosensors are known to have several advantages over conventional methods for neurotransmitter detection. This poster presentation covers the effects of metal nanoparticle (CeO2, Cu and CuO) exposure on zebrafish (Danio rerio) embryos and the impact neurotransmitter concentration measured at the level of a single organ. . One of the primary targets of exposure to nanomaterials is the digestive system of embryos where materials can localize later in embryogenesis as feeding starts. We are employing a custom-made carbon fibre microelectrodes with a modified surface to quantify serotonin and nitric oxide within the size restraints of the zebrafish embryo intestine. Initial results comprise of fixing the exposure limits for each individual metal nanoparticles. We co-relate the electrical signal obtained from the insertion experiment to the concentration of the neurotransmitters. We hypothesize that the exposure to metal nanoparticles leads to the alteration of physiological pathways by interaction between the exposed materials and the available neurotransmitters pool at intestinal level.
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.
Mxene-Based Glucose Biosensor: Strong Dependence of Exfoliation Method on Performance
Authors: Chia Hui Ling , Mayorga-Martinez Carmen , Webster Richard David , Pumera Martin
Published: May 2020

Over the last few years, the class of 2D materials has been expanded by a novel and uprising collection of early transition metal carbides known as MXenes. MXenes are synthesized via the selective etching of ‘A’ layers from their layered, ternary parent compounds, MAX phases, whereby M corresponds to early d-transition metal, A denoting a Group 13 or 14 main group sp-element, and X being either carbon or nitrogen. MXenes uniquely combine the metallic-like conductivity acquired from their parent counterparts, MAX phases and the hydrophilic nature of their surface terminating functional groups. The outstanding mechanical, chemical, physical and electrical properties of MXenes make them promising candidates for a myriad of applications, such as supercapacitors, catalysts and sensors. Inspired by the remarkable properties proffered by MXenes, we set forth to probe the feasibility of integrating MXene into a second-generation electrochemical glucose biosensor. Herein, MXenes were synthesized from their parent Ti3AlC2 MAX phase through two routes; (1) etching with 40% hydrofluoric acid (HF) (2) etching with 40% HF followed by subsequent delamination with 40% TBAOH, named Ti3C2-HF and Ti3C2-HF/TBA respectively. The heterogeneous electron transfer (HET) capabilities of these materials were examined and the superior material with the smallest peak-to-peak separation, pristine Ti3C2-HF/TBA, was then utilized to develop a glucose biosensor. Chronoamperometric measurements performed show that the proposed biosensing system displays high selectivity and remarkable electrocatalytic activity towards the detection of glucose. The glucose detection range spans over wide linear ranges of 50-27,750 µM and the proposed biosensor possesses a low limit of detection of 23.0 μM. The findings reported herein conceptually proves that pristine MXenes could be applied towards the development of biosensors and pave ways for future developments of highly selective and sensitive electrochemical biosensors for biomedical and food sampling applications.
Electrochemically Confined Nanopore Analysis: From Single Molecule to Single Cell
Authors: Lu Si-Min , Long Yi-Tao
Published: May 2020

Nanopore represents a unique and versatile sensor to analyze and manipulate single entities. We are aiming to develop a single-entity analysis platform based on the elegant electrochemically confined nanopores. The key ideal is confining the enhanced electric field within the narrow aperture of nanopore to analyze functional and dynamic information of single molecule, single nanoparticle, and single cell. Volume exclusion effect was firstly coupled with surface charge effect to track the dynamic process of Amyloid-β Aggregation. Then, we employed the confined space of nanopipette as a nano-reactor and sensing region to form a silver nanoparticle (Ag NP) electrode, and to successfully monitor dynamic process of hydrogen evolution reaction (HER) catalyzed by MoS2 quantum dots (MoS2 QDs). Furthermore, nanopipette with electrochemically confined effect also acts as nano-syringe to attract cell inclusion and deliver fluorescent molecule to a single cell. As a result, a single cell manipulating was successfully achieved.
Fabrication of Poly-Sulfosalicylic Acid Film Decorated Pure Carbon Fiber As Electrochemical Sensing Platform for Detection of Theophylline
Authors: Ding Yaping , Duan Yingchun , Wang Anqing , Li Li , Lin Jiaxin , Yu Chenhong
Published: May 2020

Theophylline (1,3-dimethylxanthine, TP) is a xanthine alkaloid that stimulates breathing system. It is widely used as a bronchodilator drug for the treatment of various asthma diseases. Determining the concentration of theophylline is important in medical affairs through simple, rapid, accurate and inexpensive methods. Electrochemical technology has got development due to its high sensitivity, stability, simplicity, low cost, ease of use, and in-situ analysis.In this work, we combined the advantage of good conductivity, large surface area of carbon fibers and the catalytic property, good biocompatibility of polymer sulfosalicylic acid to construct a novel electrochemical sensor to detect theophylline in drug analysis. The morphology of nanocomposite was characterized by electron microscopy (SEM). The polymerization between monomers was observed by Fourier transform infrared spectroscopy (FTIR). The composite between carbon material and polymer was verified by Raman spectrum. Under the optimal experimental conditions, the concentration of theophylline (0.6 ~ 137μM) and the peak current value showed a good linear relationship and the limit of detection as low as 0.2μM. In addition, the proposed sensor exhibits repeatability, stability and ease of selectivity.
Surface Engineering Cerium Oxide Nanoparticles for Biosensor Performance: Influence of Redox-Active, Oxo-Anion Ligand Modification on Sensitivity
Authors: Neal Craig J. , Sakthivel Tamil Selvan , Seal Sudipta
Published: May 2020

Nanoscale cerium oxide surface chemistry has been studied intensively due to its pronounced activity in various catalytic applications. The material’s surface reactivity is generally attributed to oxygen vacancy density and the facile inter-conversion between Ce3+ and Ce4+ redox states. However, experimental and theoretical investigations suggest a more intricate surface chemistry. In this study, cerium oxide nanoparticles (CNPs) were modified with high-valence oxo-anions to modulate surface electronic structure and chemical interactions with medically-relevant analytes. Changes to the surface chemical environment were assessed via x-ray photoelectron spectroscopy (XPS) (e.g. binding energy shifts; peak number and character), while charge transfer properties were characterized through electrochemical impedance spectroscopy and circuit fitting (following ligand@particle electrophoretic deposition in dH2O onto glassy carbon electrodes, GCE). Further, the influence of vacancy density and ligand interaction was characterized via doping Sm3+ into CNPs in varying dopant fractions (0-15 mol%; oxygen vacancy concentration increases linearly with Sm3+ concentration). From here, ligand@CNP-modified GCEs were assessed for amperometric (via chronoamperometry) and voltametric (via square-wave voltammetry) sensitivity towards catechols, ascorbic acid, and glucose in phosphate buffered saline. Time of response and selectivity (in presence of structural chemical analogues) were also assessed in similar conditions. Relative sensitivities/performances were analyzed and compared in relation to XPS and electroanalysis trends/characters for future design of optimized biosensor platforms.
Nanoceramic Powder Based Thermometer for Basal Body Temperature Monitoring System to Estimate Ovulation
Authors: M Megha , Naveen Kumar S K , Akshaya Kumar A
Published: May 2020

In this paper, Basal body temperature (BBT) monitoring IoT enabled system is designed and developed using a nanomaterial based thermistor. BBT is the lowest body temperature attained at rest and normally ranges from 96°F to 99.5°F. The NiMn2O4 nanoceramic powder based thermistor is used as a temperature sensor which is fabricated by synthesizing NiMn2O4 nanomaterial powder by the modified wet chemical method. This nanomaterial powder is pressed in an insulated cylindrical tube with aluminum electrodes. The average crystallite size of the NiMn2O4 was found to be 26.8nm from the XRD characterization. The calibration of the sensor was performed by using thin film heater, combination of LM35 and fabricated thermistor with Atmega328 microcontroller. The system so developed effectively measures the BBT at axillary (armpit) with precision more than three digits. Further this system is IoT facilitated using ThingSpeak IoT platform in order to privilege real time monitoring. Analysis of the biphasic temperature pattern of the obtained BBT graph is more convenient to predict ovulation period in women accurately. This information is helpful in enhancing the effectiveness of Natural Family Planning (NFP) to achieve or avoid pregnancy naturally.
Electroless Deposition of Iridium Oxide Thin Films on Flexible Substrates for pH Sensing Applications
Authors: Chan Tzu-Ying , Chao Wei-Ju , Tso Kuang-Chih , Hsieh Yi-Chieh , Wu Pu-Wei
Published: May 2020

The development of pH sensors is critical for a wide variety of fields including food safety, chemical synthesis, and biomedical devices. Among many materials explored for pH sensing purposes, the iridium oxide (IrO2) has attracted the most attention for its broad working temperature and pH range, as well as rapid response time and low electrical impedance. In addition, the IrO2 is chemically stable and demonstrates negligible susceptibility to redox interference. In this work, we demonstrate a formula that enables electroless deposition of IrO2 on a flexible polyimide substrate. Our formula involves the mixing of Ir3+ precursor with selective additives of complexing agent, pH adjuster, and oxidizing agent. The morphology and composition of IrO2 films are analyzed by SEM and EDS. The oxidation state of Ir in IrO2 films are determined by XPS and XAS. For pH-sensing characteristic, the potentiometric response as a function of pH value is obtained by an electrochemical workstation.
Development of Paper-Based Lateral Flow Immunoassay for Detection of Biomarkers in Human Fluids
Authors: Curtin Kathrine , Gao Xuefei , Wu Nianqiang
Published: May 2020

Rapid and accurate detection of protein and small molecule biomarkers in human blood and saliva are incredibly valuable for clinical applications. However, biomarkers are typically detected using time-consuming and expensive methods such as enzyme-linked immunosorbent assay (ELISA), Western blot, and other centralized laboratory instrumentation, so these tools cannot be used in the point-of-care setting. In this work, a paper-based lateral flow strip (PLFS) has been developed as a rapid, low-cost, point-of-care device for detecting biomarkers in whole blood and saliva. Typically, PLFSs operate using colorimetric detection and suffer from poor sensitivity and high background interference from the biological matrix. To overcome these challenges, surface-enhanced Raman scattering (SERS) and near-infrared fluorescence were applied in a PLFS as the signal transducers to improve device sensitivity and overcome biological interference. These advantages are attributed to the optical excitation in the near-infrared biological transparency window and plasmonic nanostructure enhancement. The PLFS is designed using a plasmonic nanostructures and a blood plasma separation unit for highly sensitive biomarker detection.
(Invited) Insulin and Early Diabetes Biosensors: Echem-Coupled-SPR Approaches
Authors: Krishnan Sadagopan
Published: May 2020

As per the 2017 National Diabetes Statistics Report, 30.3 million Americans (i.e., 9.4% of the population) had diabetes, and 84.1 million Americans (33.9% of the adult U.S. population) had prediabetes, which was an increase from 79 million in 2010. Diagnosed diabetic conditions cost the nation $327 billion in 2017, a 26% increase from the previous estimate of $245 billion in 2012. Thus, substantial health and economic burdens are placed on the nation. Due to the rapidly growing diabetic disorders and complications, significant needs exist for user-friendly, reliable sensors for monitoring ultra-low clinically relevant picomolar insulin and other early diabetes markers in biofluids. We explored a wide range of surface chemistries and electroanalytical techniques (eQCM, voltammetry, impedance, and amperometry) for successfully measuring picomolar serum insulin and autoantibodies from our sensor designs. Our ongoing efforts are directed towards designing new paper electrochemical devices to accomplish a label-free detection. Independent validation of our electrochemical (Echem) sensors with surface plasmon resonance (SPR) binding assays, and applications for real-sample analysis will be discussed.
(Invited) Rational Design of NIR-II Optofunctional Materials for Biomedical Applications
Authors: Li Ming
Published: May 2020

The second near-infrared (NIR-II) biological window operating in the wavelength range of 1000-1700 nm is of considerable current interest for biomedical applications. This is mainly attributed to the high biological tissue penetration depth of the NIR-II light because of the less absorption and low optical scattering. However, previous studies regarding NIR-II optical materials mainly focused on the fluorescent upconversion nanomaterials, carbon nanomaterials, organic molecules and polymers for fluorescent bioimaging, photothermal/photodynamic therapy, and photoacoustic imaging. As is well-known, these optofunctional materials have limitations of low fluorescence efficiency, poor stability and poor multifunctionality. This talk will introduce NIR-II plasmonic materials recently developed in our lab for biomedical applications. We have developed NIR-II plasmonic Au-Ag nanostructures, copper chalcogenides and their hybrids with excellent optical properties tunable by their size, composition and structure. We have demonstrated the excellent plasmonic properties of these materials and systematically elucidated their structure-plasmonic property relationship. We also exemplified the applicability of these NIR-II optofunctional materials for SERS biosensing, photoacoustic imaging, CT, and light-assisted cancer therapy with excellent performance. We believe that these NIR-II plasmonic materials hold considerable potential for multimodality theranostics of cancer.
(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) Engineering the Bio-Interface at the Micro and Nanoscale for Applications in Diagnostics and Therapeutics
Authors: Fatanat Didar Tohid
Published: May 2020

The biological/non-biological interface system is an important cornerstone for the fabrication of a wide range of biomedical devices. Platforms as diverse as lab-on-chip and point-of-care diagnostics, 3D tissue culture scaffolds, organs-on-chips and implants all rely on the effective interaction of cells and/or bio-recognition elements (proteins/peptides, enzymes, oligonucleotides, etc.) with non-biological surfaces. Design and engineering of micro/nano patterned interfaces provide powerful tools to study biological phenomena at micro and nano scale and to develop novel technologies for diagnostics and therapeutics. I will present an overview of our research on micro/nano-scale design of novel biomedical coatings and their integration into in vitro systems such as lab on chip, organs-on-chips and flexible sensing interfaces as well as in vivo applications to develop efficient medical devices such as catheters, vascular grafts and extracorporeal circuits.
(Invited) Paper-Based Optofluidic Devices for Point-of-Care Testing
Authors: Wu Nianqiang
Published: May 2020

Surface-enhanced Raman scattering and near-infrared fluorescent sensors have been incorporated into the paper-based lateral flow strips to realize the automatic, miniaturized and portable device. This type of devices has been used as the point-of-care tool for testing biomarkers of diseases such as cancer and traumatic brain injury (TBI).
(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
Electrochemical Microarray System for Acute Biomarker Detection Assessment for Point-of-Care (POC) Cancer Diagnosis
Authors: Ling Pinghua , Nguyen Vincent , Huang Xiaozhou , McGhee Aungelique , Massey Gabrielle , Merrell Asriel , Riley Kevin , Dong Pei , Wang Zhe
Published: May 2020

The research on biomarker detection has increased dramatically in recent years and many strategies has emerged. However, current methods for identifying specific biomarkers and small molecules for point of care (POC) diagnosis outcomes suffer shortcomings of limited specificity and complex procedure in the measurement and the lack of real-time analysis to establish a causal relationship between an individual's profile and impact on health. The goals of our research are 1) to provide researchers with a new tool to better assess the impacts of biomarkers and small molecules for the cancer diagnosis and treatment and 2) to provide individuals with an inexpensive benchtop device for rapid reporting of exposure data for personalized alerts and managed care services. To achieve these goals, we are exploring several key technologies and approaches that will enable implementation of a novel autonomous sensorarray microsystem for acute multi-analyte assessment, such as sulfatases, antibody/antigen and micro-RNA/RNA, with the sensitive real-time monitoring. Electrochemistry signals were classified and quantified during the bio-interactions on the designed electrode interface, exhibiting the excellent sensitivity and specificity for targeting biomarkers without adding signal media and label. This project would provide medical researchers and physicians with a much needed and currently non-existent tool for personal treatment assessment and decision, leading to more relevant disease regulation, intervention for individuals diagnosis, and ultimately improvement of overall public health.
(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) Plasmon Enhanced IR Spectroscopy and Electrochemistry
Authors: Xia Xing-Hua
Published: May 2020

The localized surface plasmon resonance (LSPR) arises from the collective oscillation of conduction electrons of metal nanostructures which can be used to monitor recognition events of biomolecules at single nanoparticles1. The enhanced electric field around the nanostructures due to LSPR will significantly enhance the Raman scattering, fluorescence and IR spectra, which enable the realization of single molecule detection. In addition, the LSPR will excite high-energy electron-hole pair (referred to as “hot electrons” and “hot holes”) emerging on metal surface. The energetic charges will considerably affect the electrochemical reactions occurring at the nanoparticles. When the plasmonic metallic nanostructures are coupled to other substrates, for example, the semiconductor (i.e., TiO2, MoS2), the plasmon-excited hot electron-hole at nanoparticle surface can communicate with the conductance and valence bands of the semiconductors, resulting in variation in electro/photocatalytic activity. In this talk, we will start with the LSPR enhanced IR for biosensing.1 Then, we will show how the LSPR accelerates electrochemical reactions of electroactive biomolecules such as glucose on gold nanoparticles and hydrogen evolution reaction at molybdenum disulphide nanosheets.2 Based on the plasmonics accelerated electrochemical reactions (PAER), high sensitive electrochemical biosensors for detection of glucose and other electroactive biomolecules have been constructed.
(Invited) Nanoscale Engineering of Plasmonic Materials for Biosensing and Bioimaging
Authors: Xie Fang
Published: May 2020

Early diagnosis plays an increasingly significant role in current clinical drive. Detection, identification, and quantification of low abundance biomarker proteins form a promising basis for early clinical diagnosis and offer a range of important medical benefits. Amplification of light from NIR fluorophores by coupling to metal nanostructures, i.e. Metal Induced Fluorescence Enhancement (MIFE), represents a promising strategy for dramatically improving the detection and quantification of low abundance biomarker proteins, and potentially increase already sensitive fluorescence-based detection by up to three orders of magnitude. The amplification of the fluorescence system is based on interaction of the excited fluorophores with the surface plasmon resonance in metallic nanostructures. The enhanced fluorescence intensity due to the existence of metal nanostructures makes it possible to detect much lower levers of biomarkers tagged with fluorescence molecules either in sensing format or for tissue imaging. The first part of my talk will focus on some recent developments of plasmonic metal nanostructures by both “top-down” and “bottom up” methods. I will then discuss the prepared plasmonic nanostructures in the applications of biosensing and bioimaging, with the emphasis on plasmonic enhancement towards NIR I and NIR II regions.
(Invited) Intelligent Wearable Biosensors—Progress and Problem
Authors: Xu Tailin , Zhang Xueji
Published: May 2020

Artificial intelligence (AI) and wearable sensors are two fields that are instrumental in realizing the goal of precision medicine—tailoring the best treatment for individual patients. Recent development between these two fields is enabling better patient data acquisition and improved design of wearable sensors for monitoring the wearers’ health, ﬁtness, and their surroundings. The growing field of wearable sensors aims to tackle the limitations of centralized, reactive healthcare by giving individuals insight into the metrics of their own physiology. However, assessing the effectiveness of a therapeutic platforms on disease is extremely complex, due to the massive quantities of data generated by biomedical devices. Integration of AI approaches can bridge this gap, using pattern analysis and classification algorithms for improvement of diagnostic and therapeutic accuracy. The future AI-biosensors (AI wearable sweat biosensor, AI- eatable biosensor, AI-glass biosensor, AI-implantable biosensor et al.) mainly have the function of AI-diagnosis (Diagnostic algorithms in the microprocessor can verify the output of the sensor and present the diagnostic information), Big data processing (Use of self-contained space for historical data and various necessary parameters of data storage to greatly improve the performance of the controller.) and Self-learning/adaptive (Embedded microprocessor with advanced programming function. In the working process, the AI-biosensor can reconstruct the structure and parameters according to certain behavioral criteria, and has adaptive functions)
Novel Solid Electrolyte CO2 Gas Sensors Based on c-Axis-Oriented Y-Doped Lasibo
Authors: Ma Nan , Ide Shingo , Suematsu Koichi , Watanabe Ken , Shimanoe Kengo
Published: May 2020

Nowadays monitoring and recording CO2 gas becomes more and more important in various areas, leading to an increasing demand for developing high-sensitive CO2 sensors. In this study, a novel potentiometric CO2 gas sensor is designed based on a new solid electrolyte of Y-doped La9.66Si5.3B0.7O26.14 (Y-LSBO), coated with Li2CeO3-Au-Li2CO3 composite as sensing electrode and Pt as reference electrode. With optimized composition of sensing electrode, the EMF varies linearly with the logarithm of CO2 concentration in the range of 400-4000 ppm, exhibits an excellent Nernstian response to CO2 gas in both dry and humid atmospheres. The functionalization of optimized Li2CeO3-Au-Li2CO3 composite on Y-LSBO solid electrolyte give rise to the formation of an interfacial layer, serving as an “ionic bridge” between the O2- conductor (Y-LSBO) and the Li+ conductor (Li2CO3). Therefore, the designed sensor device can track CO2 concentration by monitoring EMF change, and exhibits an excellent Nernstian response to CO2 gas both in dry and humid atmospheres. This study provides the possibility of Y-LSBO solid electrolyte as a potentiometic gas sensor to measure CO2 in the environment, demonstrating that Y-LSBO is not only a promising solid electrolyte for oxygen pump and solid oxide fuel cell but also for gas sensor.

Figure 1