12^th International Conference & Exhibition on Biosensors & Bioelectronics October 25-26, 2019 | Vancouver | British Columbia | Canada

Shiping Song obtained his PhD in Inorganic Chemistry at Shanghai Institute of Applied Physics, Chinese Academy of Sciences (CAS), in 2004. He currently holds position as Professor in the Division of Physical Biology at Shanghai Advanced Research Institute, CAS and is a Humboldt Scholar in the Institute of Inorganic Chemistry at the University of Cologne. His expertise is in the field of nanomaterials, microscale structures and biological analysis, with a special focus on nano-based biosensors and biochips. He has co-authored more than 140 articles and chapters. He is an ad hoc reviewer for more than 20 international journals, as well as for several granting agencies.

Statement of the Problem: Biosensors and biochips have greatly promoted the development of the fields of genomics, proteomics, and clinical assays because of their remarkably rapid and high-throughput assay capability. Immobilization strategies for biomolecules on a solid support surface play a crucial role in the fabrication of high-performance biosensors and biochips.
Methodology: Rationally designed DNA tetrahedra carrying three thiol/amino groups and one single-stranded DNA extension were synthesized by the selfassembly of four oligonucleotides, followed by high-performance liquid chromatography purification. We fabricated DNA tetrahedron-based biosensing chips by covalently coupling the DNA tetrahedron onto gold/silicon/carbon substrates. After their biorecognition capability was evaluated, DNA tetrahedron biosensing interfaces were utilized for the analysis of different types of bioactive molecules. The gap hybridization strategy, the sandwich configuration, and the engineering aptamer strategy were employed for the assay of miRNA biomarkers, protein cancer biomarkers, and small molecules, respectively.
Findings: The arrays showed good capability to anchor capture biomolecules for improving biorecognition. Addressable and high-throughput analysis with improved sensitivity and specificity had been achieved. More importantly, we demonstrated that the biosensing platform worked well with clinical serum samples and showed good relativity with conventional bioassays.
Conclusion & Significance: We have developed a novel approach for the fabrication of DNA tetrahedron-based biosensing chips and a universal DNA tetrahedron-based biosensing platform for the detection of different types of bioactive molecules. The biosensing platform shows great potential for practical clinical diagnosis.

Woochang Kim is currently doing his PhD course in Department of Control and Instrumentation Engineering, Korea University, Sejong, South Korea. His research focuses on detection of toxic nanomaterials. He is also interested in thermal and thermoelectric properties of nanomaterials.

Fibrinogen which is a glycoprotein is an important biomarker of various disorders such as cardiovascular diseases to hemophilia. Therefore, quantitative assay for fibrinogen in the blood has emerged as an important issue for the prevention and diagnosis of these diseases. In this study, we made an erythrocyte membrane (EM) covered biosensor based on localized surface plasmon resonance (LSPR) that can detect fibrinogen over a wide range of concentrations. We demonstrated that the concentrations of fibrinogen could be differentiated in the range of 0.001–5.000 mg/mL, which can cover normal and pathological blood fibrinogen levels after coating of the surface of the LSPR biosensor with EMs. This wide-range fibrinogen assay has excellent advantages in detecting a fibrinogen excess or deficiency in plasma samples

Claudy D’Costa has a background in electronic instrumentation as well as sensor and biodevice development with expertise in microfluidic platforms. In SUREAQUA, he is developing a lab-on-a-chip biosensing platform to detect various environmental factors including physical, chemical and biological parameters in aquaculture systems. There has been special emphasis given to developing a microfludic platform using industrial techniques, such as injection moulding, ultrasonic welding, cleanroom fabrication to facilitate upscaling of fabrication throughput.

Statement of the Problem: Modern aquaculture systems are aimed to provide a sustainable and resilient way of farming fish to meet the world demand. There are conventional sensors for these systems to measure the basic parameters, e.g., temperature, pressure, salinity, turbidity, pH, BOD. Although these parameters provide information on the basic environment for the survival of the fish, it provides neither viable data on the welfare of the farmed fish nor the effect of such a farm on the outside environment due to use of certain fish feeds containing harmful chemicals or pesticides. To address these additional parameters, ongoing research addresses development of various sensors to detect pesticides, hormones and harmful chemicals. Most of these systems have shown promise in the lab but have failed to mature into a commercial product. There is also a lack of policy which details on the various acceptable levels of harmful substances either in the farm or when released into the environment. Hence, the current project focuses on constructing a useful sensor that can be industrially manufactured to detect such substances in order to obtain information about the welfare of the fish. To maintain fish stress-free in the aquaculture system is an important aspect for its welfare as well as the economy, since stress can adversely affect the growth rate and the final mass. In this project, we are construct a fluidic immunobiosensor chip for detecting cortisol, the stress hormone, released into the surrounding water. This measurement acts an early warning regarding the status of optimal conditions required for a stress-free environment and, thus, better growth. The biosensor chip is developed with an inbuilt preconcentration system and integrated electrodes for electrochemical detection only using industrially applicable manufacturing techniques. We demonstrate a system capable of trace analysis directly from the water facilitated by the preconcentration through a supported liquid membrane. The fluidic system is constructed using injection molded components and the electrodes are directly fabricated on them. The assembly of waterproof devices is done by ultrasonic welding.

“Ray” Duanghathaipornsuk received the BS degree in industrial chemistry from Chiang Mai University, Thailand. Currently, he is a Chemical Engineering PhD candidate in the University of Toledo, has been working on free radical sensor development for three years and has played a critical role in developing the sensor for hydroxyl radical detection. He is interested in the research area of using inorganic nanocatalyst for developing a sensor array.

Free radicals are recognized as essential molecules for upholding the function of normal cells. The immune systems such as eliminating bacteria and inactivating virus are the example for the crucial role of free radicals in cells. Even though free radicals have benefits on human cells, the optimum production is the key to maintain their advantages. High concentrations of free radicals in a human body may cause cancer, Alzheimer’s disease or Parkinson’s disease. Among several free radical species, hydroxyl radicals (•OH) are the highest reactive and the most dangerous free radical. •OH is also one of the biomarkers that are identified during an initial stage of severe disease development. Thus, to diagnose the developing of those diseases, a very sensitive analytical sensor is needed for •OH detection at low concentrations. The integration of an electrochemical technique with a sensing system is regarded as a promising method for •OH detection due to a rapid and direct measurement without the pretreatment of samples. Thus, in this study, a glassy carbon electrode (GCE) was modified with Vulcan carbon/cerium oxide nanoparticles (CeO2 NPs) composite to be used as a sensing device for •OH. The composite of Vulcan carbon/CeO2 NPs was synthesized through the controlled surface reaction. X-ray powder diffraction (XRD) helped to confirm the composition of the Vulcan carbon/CeO2 NPs composite. Transmission electron microscopy (TEM) was used to determine the average size of CeO2 NPs in the composite. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were implemented to characterize the interaction of the composite sensor with •OH. The GCE modified with Vulcan carbon/CeO2 NPs composite was used to detect •OH in Fenton reaction compared to bare GCE. As expected, there is no oxidation current response occurring from the bare GCE. The modified GCE, however, showed a significant increase in oxidation current response. Moreover, it demonstrated the linear relationship between oxidation current response and •OH concentration in the range of 0.1 mM to 10 mM. From the preliminary result, it is suggested that the Vulcan carbon/CeO2 NPs composite can be used to modify the sensor for •OH detection.

Ang Wei Li is pursuing a second year in PhD student at the Nanyang Technological University, Singapore. He is currently researching on the development of biosensors by use of zero-dimensional nano-sized Graphene Quantum Dots as the biosensing platform.

The consistent need for a simple and affordable biosensor is of utmost importance, owing to the increase demands for a straightforward analysis of food quality and food safety. As such, Graphene Quantum Dots (GQDs) was utilized, not only as the platform for the biorecognition element but also function as nanoquenchers for the optical detection of a major food contaminant, Ochratoxin A (OTA) in food. Therefore, GQDs, was employed as the biosensing platform in conjunction with a fluorescent-labelled DNA aptamer (FAM OTA Aptamer) as the biorecognition element towards the optical detection of OTA. The detection principle lies in the formation of non-covalent interactions between the biorecognition element and the platform, resulting in a decrease in the fluorescence intensity of the initial signal from the fluorescent label. Further changes in the signal, resulting from the formation of the FAM OTA Aptamer/OTA conjugate during the detection step, could be correlated to the quantification of the target analyte in solution. It was uncovered, in this work that a switch in the biosensing mechanism could be achieved by controlling the concentrations of the GQDs utilized with 0.060 mg/mL resulting in a further decrease of the signal and 0.150 mg/mL resulting in a restoration of the signal upon subsequent incubation with OTA. Interestingly, the switch in the behavior was determined to be at 0.115 mg/mL.

Iwe Idorenyin is a PhD student in Department of Mechanical and Aerospace Engineering at the Hong Kong University of Science and Technology, Hong Kong. His research areas primarily focus on energy harvesting and biosensing. He is very interested in utilizing novel materials to improve the sensitivity, selectivity, and cost of biosensors for applications in biomedical research, forensic investigation, and clinical diagnosis.

We report a dual-cycling amplification method for DNA detection. The method employs graphene oxide (GO), digestive enzyme (Exo III), and two specially designed, fluorophore-labelled hairpin probes (HP1 and HP2). It comprises two reaction cycles to enhance fluorescence generation. In cycle I, the target DNA is repeatedly used to amplify fluorescence signal through continuous hybridizations with HP1 and the cleavage of HP1-target DNA complex by Exo III. A segment of HP1, which is the product of cycle I reactions, hybridizes with HP2 in cycle II, triggers Exo III to cleave HP2, and free the fluorophore attached to HP2, leading to the enhancement of fluorescence emission. Without the target, GO quenches the fluorescence of the sensing system via the adsorption of HP1 and HP2 on GO surface, which greatly lowers the signal generation. The GO exhibits distinct adsorption affinities towards a short and long single-stranded DNA and modulates fluorescence signal production upon the presence of target DNA. The limit of detection is experimentally determined as 1 pM, which is 2 to 3 orders of magnitude lower than the other methods with nanomaterials as the signal enhancer. The feasibility of the method for real samples is demonstrated in fetal bovine serum.