7^th Euro Biosensors & Bioelectronics Congress July 10-11, 2017 Berlin, Germany

James Seckler has completed his PhD at Case Western Reserve University, and Post-doctoral studies at University of Rochester and Case Western Reserve University. He is currently a Postdoctoral Fellow in Department of Pediatrics at Case Western Reserve University. His field of study includes experimental and theoretical protein dynamics, FET capacitive sensors, and studying role of S-nitrosothiols in biological tissues

Small molecule S-nitrosothiols are endogenous chemicals which are produced by various forms of nitric oxide synthase. Their regulation plays a key role in the control of a variety of bodily processes and disease models, including: breathing, blood pressure, pulmonary hypertension, and asthma. However, these molecules are extremely labile, making in vivo detection extremely challenging as most small molecule S-nitrosothiols exists at very low concentrations in the body. We have developed a capacitive biosensor which employs poly-dopamine as its sensing and functional layer. A thin film of poly-dopamine behaves like a semiconductor and also will covalently crosslink to all free amines, free thiols, and S-nitrosylated thiols in solution. We treated with formaldehyde to block all free amines and free thiols, leaving only the S-nitrosothiols. S-nitrosothiol bonding to the semiconducting surface of the sensing electrode changes its capacitance, allowing for extremely sensitive detection of S-nitrosothiols in biological samples. We will present evidence of attomolar detection of S-nitrosocysteine which can be abolished by the addition of mercury to the fixing buffer, or by exposing the sample to UV light during fixing, both methods of degrading S-nitrosothiols. We will also present evidence of the presence of small molecule S-nitrosothiols in blood and saliva.

Katja Hahne studied Human Biology at University of Greifswald. During her Diploma thesis, she dealt with the determination and the influence of peroxidase activity in human saliva and peroxidase containing products. Since 2015, she has been working as a PhD student at Institute of Genetics, Technische Universität Dresden. Within the Rödel group, her research is located in the field of “Biological sensor-actor systems”

BioSAM, an innovative regional growth core funded by the BMBF, encompasses 11 companies and six research institutions that are focusing on applications of whole cell sensors in biotechnology, environmental and medical technology. Besides their high sensitivity and specificity, whole cell based biosensors indicate the bioavailability of a specific analytes. The project Biogas aims to generate functionalized yeast cells as sensors for the control and optimization of the biogas process. Acetic acid as a critical intermediate was defined as the key analytes. The accumulation of acetic acid indicates an imbalance of the process due to a kinetic uncoupling between acid producers and consumers. Monitoring of acetic acid may thus assist optimizing the biogas process. We here describe the generation and validation of yeast whole cell sensors which modulate the expression of a fluorescent protein depending on the concentration of the analyte. In order to increase the endurance of a monitoring device, in addition to vegetative cells, spores are tested for the monitoring process

Aaron is in the 2nd year of his PhD at the Ulster University in Northern Ireland. He currently has published 3 papers in reputed journals, with several others at various stages of completion and in review. He has significant involvement in module co-ordination and delivery of material to engineering undergraduate students in the university at which he studies, as well as supervision of Biomedical Engineering undergrauate students throughout their final year projects

Hydrogen peroxide (H2O2) is one of the several reactive oxygen species (ROS) generated as a by-product of many biological processes. While it occurs naturally in relatively low concentrations throughout the human body, deviation from the normal physiological range may be indicative of a number of conditions. As such, hydrogen peroxide may be viewed as a biomarker, allowing it’s concentration to be monitored and thus used to augment diagnosis of critical ailments such as sepsis and oxidative stress. To this end, we have sought to investigate the development of a non-enzymatic sensor capable of quantifying peroxide. The core aim of the approach relates to the provision of a micro scale sensor that could be ultimately be used for in vivo measurements or transdermal sensing. The underpinning methodology pursued involves the design and development of a monofilament carbon fiber probe (10 micron diameter) onto which a nano layer of palladium is electrochemically deposited. Examination of the latter using scanning electron microscopy revealed a forest of Pd nano fibrils and a representative image highlighting the partial formation of the film is shown in Figure 1. These structures have been shown to exhibit exceptional catalytic activity towards the oxidation of peroxide at low operating potentials where there is very little interference from other matrix components. The high sensitivity and selectivity for peroxide can be further exploited through coupling of oxidase enzymes to expand the range of biomarkers that can be quantified. The subsequent modification of the Pd film and the extrapolation of the amperometric approach to the measurement of glucose and lactate (itself an important marker of sepsis) is considered and critically appraised

Elizabeth is a second-year Master of Science candidate in the Chemical Biology Graduate program at the Biointerfaces Institute (McMaster University) in Hamilton, Ontario, Canada. Elizabeth previously obtained a Bachelor of Science degree in Chemical Biology with a minor in Biology from McMaster University. Currently working under Dr. John Brennan, her research predominantly focuses on paper-based biosensors, as well as applications of microbial biosensor technologies for pollutant detection. Her current work is concerned with the preservation of microbial biosensors through drying in natural polymers such as pullulan, in order to increase the utility of these sensors for field applications. Elizabeth is currently a recipient of two departmental awards from McMaster University

Air drying in the natural polymers pullulan and acacia gum has been reported previously as an effective bacterial preservation strategy. The use of this method for the preservation of sensing bacteria is presented here. Colorimetric Escherichia coli bioreporters for tetracycline and arsenate analytes has retained responsivity following air-drying in pullulan sugar. Additionally, the method was used to immobilize sensing cells onto paper substrates, and a screen of various materials was conducted to determine the optimal composition of a drying matrix for responsivity. The viscosity enhancer pullulan, acacia gum, polyvinylpyrrolidine and gelatin were paired with osmoprotectants in some standard bacterial culture mediums. The air-drying process is simpler, less expensive, requires less sophisticated instrumentation, and leads to much higher bacterial survival rates compared to the gold standard method for bacterial preservation, lyophilization. Simplicity of the method paired with applicability to simple platforms such as paper test strips makes this research an important step toward the usage of sensing microbes for the detection of a variety of biologically relevant analytes in the field

H Haraguchi is pursuing her BA at Toyo University. Since 2015, she has been exploring ways to commercialize LSPR sensors under the supervision of Professor H Takei

We describe an LSPR sensor based on cap-shaped noble metal nanoparticles, prepared with a metal film on nanospheres (MFON) method. In contrast to the standard MFON, we use randomly adsorbed nanospheres that significantly facilitate the fabrication process without any sacrifice in performance. Moreover, adding a 20 nm thick Au layer beneath the nanosphere layer was found to lead to a pronounced increase in the absorption peak. The nanosphere diameter is typically 100~150 nm with the top metal layer thickness in the range of 20 nm. These samples are characterized by peaks both in visible and near-IR regimes. The near-IR peak has refractive index dependence greater than 500 nm/RIU, some four times better than the visible peak. While the improved sensitivity is very encouraging, we need to overcome a number of technical challenges before we can implement the sensor for characterization of antibodies as pharmaceuticals; in particular the presence of NaCl leads to an overall drift in the peak wavelength which is attributed to change in nanoparticle morphology. We have solved this problem by coating nanoparticles with a layer of various thiol molecules. Those thiols were either sublimed or vaporized. Vaporized 1-butanethiol was found to be better at protecting the nanosphere layer. We also found that the same set of thiol treatments could stabilize Ag nanoparticles which are normally considered as too reactive for use as a sensor material. We foresee applications such as in-situ characterization of antibodies while still in the fermentation process or immediately prior to use

K Nagata is pursuing his BA at Toyo University. Since 2015, he has been working on “Exploitation of butterfly scales for SERS applications under the supervision of Prof. H Takei"

We will discuss exploitation of naturally-existing nanostructures for bio-analytical techniques, specifically surface-enhanced Raman spectroscopy (SERS). Raman spectroscopy is one of the few analytical techniques capable of giving information on chemical structures without need to place the sample in a vacuum, making it well suited for on-site inspection of chemical species as in environmental monitoring, forensic sciences and quality control. There are already a number of commercial vendors selling SERS substrates, but the price needs to be reduced significantly in order to make this technique widely used. Our group has been investigating: Random-MFON structures whereby randomly adsorbed SiO2 nanospheres are coated with a noble metal and; silver dendrites grown from surface-adsorbed base metal nanoparticles in a AgNO3 solution. Here, we report on yet another method based on exploitation of scales of butterfly wings. We found that coating of butterfly wing scales, characterized by intrinsic nanostructures, with silver gives rise to a surface capable of showing SERS effects. While effectiveness depends on the butterfly species, precise scales within a single wing, the amount of deposited silver etc., there is a surprising uniformity in SERS signal intensities when these parameters are selected appropriately. By exploiting naturally-existing nanostructures, we can minimize the number of manufacturing steps, thus, reducing the overall cost. We can also obtain basic information on secret as to what makes a particular nanostructure work by selectively altering the underlying nanostrucures. This would give us an option of artificially recreating the crucial nanostructures

Jaewon Kim has completed his Master’s degree at Sungkyunkwan University. Now, he is pursuing PhD in Mechanobiology at the same university

Cells react variously to external mechanical stimuli such as shear stress from fluid flow or tensile stress caused by substrate deformation. As a result, their structural and functional properties are largely affected by these mechanical stresses, and this phenomenon has been extensively investigated by using cell stretching devices. However, conventional cell stretching devices still have technical limitations to observe such complicated cellular responses. For example, many cell stretching devices are too large to be placed on the stage of microscope and often generate excessive heat and vibration, which are harmful for cells. To overcome these technical limitations, we developed a new type of cell stretching device which can be operated either statically or cyclically by pneumatic force to reduce the generation of excessive heat and vibration. In addition, its size is small enough to be placed on the stage of the microscope. We demonstrate the feasibility of the stretching device for application in cellular experiments by observing the effect of static stretching longitudinally on cell junction and its structural instability in intestinal epithelial cells

Ibragimova Sagila Aladdinovna completed her Graduation with honors at State University of Dubna in Department of Chemistry, New Technologies and Materials and defended her Master's thesis entitled “Synthesizing quantum dot conjugates with monoclonal antibodies to glycoprotein gB of Aujeszky's disease virus for immunochromatographic analysis” in 2016. Her scientific work is related to the immunochromatographic analysis using as markers and quantum dots. She is Co-author of four books, has two patents and participated in nine national and international conferences.

There is large number of different markers used in immunochromatographic analysis (IChA). The use of quantum dots markers fluorescent in near infrared (NIR) region is promising in bioassay. We investigated here sandwich method of IChA. Quantum dots (QDs) exhibit strong and narrow band-edge luminescence. Due to their unique optical properties, QDs are perfect fluorescent markers for molecular diagnostics of diseases. It is possible to synthesize QDs with fluorescence in NIR, where background fluorescence of biological samples is low. Highly bright and photo-stable NIR-emitting CdTeSe/CdS/CdZnS QDs were synthesized following the method. QDs were functionalized with COOH-group using thiol-modified polyvinylpyrrolidone. As a model antigen, we used glycoprotein gB of nonpathogenic for human being Aujeszky's disease virus. QDs were covalently conjugated with monoclonal antibodies to glycoprotein gB of the virus using carbodiimide methods. The conjugates were tested on test strips manufactured by following the method. The investigation showed that the optimal excitation wavelength was of 450 nm, where the background luminescence was low and fluorescence peaks of test and control zones test strip were more pronounced. Calibration curve for the quantitative determination of antigens was drawn in a range up to 25 fmol in the sample. Antigen limit of detection is of 4.2 fmol in the sample.

Giorgi Shtenberg completed his PhD in 2014 in Biotechnology and Food Engineering at Technion–Israel Institute of Technology. He has expertise in Nanomaterials, Semiconductors, Microfluidics, Photonics and Biological Interfaces for biomedical and environmental monitoring applications. He is currently a Scientist and Head of Bio-Nano-Laboratory at Institute of Agriculture Engineering, ARO-The Volcani Center. He is focusing on the development of novel biosensors/bioassays that will transform from a laboratory-based research into real on-site “lab-on-chip” platforms for addressing problems in fields of agriculture, animal diagnostics, food safety and environmental monitoring and detection

The effect of thermal oxidation conditions on the behavior of porous Si optical biosensors, for label-free and real-time monitoring of enzymatic activity, is studied. We compare several oxidation temperatures and their effect on the enzyme immobilization efficiency and the intrinsic stability of the resulting oxidized porous Si (PSiO2), Fabry-Pérot thin films. Importantly, we show that the thermal oxidation profoundly affects the biosensing performance in terms of greater optical sensitivity, by monitoring the catalytic activity of horseradish peroxidase and trypsin-immobilized PSiO2. Despite the significant decrease in porous volume and specific surface area, with elevating the oxidation temperature, higher content and surface coverage of the immobilized enzymes is attained. This in turn leads to greater optical stability and sensitivity of PSiO2 nanostructures. Specifically, films produced at 800°C exhibit stable optical readout in aqueous buffers combined with superior biosensing performance. Thus, by proper control of the oxide layer formation, we can eliminate the aging effect; thus, achieving efficient immobilization of different biomolecules, optical signal stability and sensitivity