Biosensors Conference

Abstract
Point-of-care electrochemical immunosensors are promising strategies for next-generation
diagnostics due to the cost-effective, practical usage and smart response. Although screen-printed
immunosensors have undergone have undergone a major revolution after Covid19, the detection of
antigens or antibodies with point-of-care devices is still a major challenge due to several limitations,
including many steps required to reveal the reactions, non-practical response, time-consuming results
and a low reproducibility, which are also due to the adsorption of the redox probe on the sensor
surface. To overcome these challenges, some strategies have focused on removing the ferrocyanide
by adsorbing the redox probe to the electrode surface or excluding it from the measurements to allow
direct measurements. This study describes the use of ferrocene as mediator directly immobilized on
the sensor surface by complexing it with graphene nanoplateles,/graphene The transport of the redox
species from the electrode generates the amperometric signal, which is proportional to the lower
diffusion of the species on the electrode surface that is hindered by the adsorbed insulating antigen
or antibody. Electrochemistry of ferrocene and its derivatives is well known, being attractive due to
its excellent stability, electrochemical reversibility by oxidation of iron II. This study describes an
electrocatalytic graphene adsorbed on sensor surface as a proof-of-concept, confirming antigen
detected by direct measurements without any additional redox probe for revealing the reactions.

Biography
: Rosa Fireman Dutra is associate professor at the Federal University of Pernambuco
(UFPE), Brazil. She is Leader of Biosensors and Bioengineering Research Group, Electronic
Engineer and has gone her PhD in biosensors area (Brazil) with focus on point-of-care devices.

Abstract
Recently, bio-field effect transistor (bioFET)-based devices have attracted significant interest due to their sensitivity and specificity, which are comparable to conventional methods. In a FET device, current flows between two electrodes through a semiconductor channel, while a third electrode (gate) regulates conductance. When biological probes are immobilized on the gate surface and capture a target, they release charges to the gate, altering the gate voltage and influencing the source-drain current. This current variation is directly correlated with the concentration of the target. This technology was exploited to detect different biomolecules, including microRNAs which are small non-coding RNAs involved in the onset and progression of many disease. Despite this straightforward operating principle, several challenges hinder the transition of bioFET technology from academia to clinical diagnostics such as the choice of probes and the hybridisation conditions.To address these issues, we used a bioFET platform conjugated with an innovative synthetic peptide nucleic acid (PNA) probe to directly detect human microRNA 155 (miR-155), whose altered expression is associated with various pathologies, including different cance types. Before conducting biosensing experiments, we evaluated and characterized the interaction kinetics between immobilized PNA and miR-155 using Surface Plasmon Resonance (SPR) technology. The results indicate that PNA exhibits high affinity for miR-155. Consequently, when integrated with the proposed bioFET system, this probe enables fast, specific, direct, and label-free detection of miR-155, achieving a limit of detection (LOD) of approximately 5 nM under physiological-like conditions.
Biography
JFrancesco Lavecchia di Tocco earned his Master’s Degree in Biology from the University of Perugia in 2021. Following this, he got a fellowship in 2022, funded by the Italian Association for Cancer Research (AIRC), focusing on the development of biosensors for microRNAs at the Biophysics and Nanoscience Center (BNC) of the University of Tuscia. He is currently in his second year of a PhD program in Biomedical Sciences and Technologies at the University of Roma Tre, focusing on electrochemical biosensors for detecting microRNA 155. His early research contributions have resulted in the publication of two papers.

Abstract
Respiratory infections are among the top two causes of treat-and-release Emergency Department (ED) visits in the USA. Globally, respiratory infections accounted for ~42.8% of all-cause illnesses in 2019. The combined forces of rapid urbanization, globalization, and easy international travel have heightened the risk of widescale transmission of respiratory infections, thereby posing an increased threat to public health. This strain became especially evident in the recent COVID-19 pandemic, which resulted in ~6.9 million deaths globally.We developed a breathalyzer to rapidly detect SARS-CoV-2 in a single breath. It combines recent advances in breath aerosol sampling technology and an ultrasensitive biosensing technique. A research prototype of the device, recently published in ACS Sensors, will serve as the platform for the development and validation of the multi-pathogen biosensor/breathalyzer. Preliminary human data from COVID-19 patients collected through clinical trials conducted at the WUSTL Infectious Disease Clinical Research Unit (IDCRU) has demonstrated the feasibility and specificity of the technology in breath-based diagnosis. The time from breath into the device to read-out of infection (or not) is under 60 seconds. The biosensor detects all current strains of SARS-CoV-2 and is sensitive to 20-50 viral particles per milliliter depending on the strain. The electrochemical sensor uses voltammetry to measure oxidation of tyrosine amino acids within a protein. Oxidation is the release of electrons that the carbon fiber electrode detects as a change in current. The amount of current is proportional to the amount of protein present. The biosensor uses a llama nanobody (antibody) that is covalently attached to the surface to provide specificity and concentrate the protein at the electrode for measurement. The device collects an exhaled breath condensate on to a chilled hydrophilic surface. Rapid detection of a respiratory pathogen can be used in mass screening of individuals as they file into indoor spaces, such as airport security areas, office buildings, conference centers, mass transit hubs, or military vessels. Having test turnaround times of 60 seconds allows for large queues of individuals to be screened rapidly, then either admitted or quarantined away from the group. In addition, the breathalyzer could also be used in point-of-care (POC) locations, such as local clinics or pharmacies. The team at Washington University has worked in close conjunction with Y2X Life Sciences with an eye on commercialization throughout the research and development phases.
Biography
John worked with Dr. Michael Numan (Psychology) studying the neural circuits underlying maternal avoidance in rats. He graduated in 1998 and spent a year working in Research and Development at NEN Life Sciences (now Perkin Elmer) developing research reagents, including some that his own lab still uses. In 1999 he started his PhD in Neuroscience at Washington University in the lab of Dr. David Holtzman (Neurology) studying Alzheimer’s disease. Much of his PhD work focused on the proteins and cellular pathways that eliminate amyloid-beta (Aβ) from the brain. Here he developed the first use of in vivo microdialysis to study Aβ kinetics in the brain of a living mouse. John received his PhD in 2005, then became a post-doc in the lab of Dr. Steven Mennerick (Psychiatry) where he learned to pretend to be an electrophysiologist to study synaptic processes that regulate Aβ generation. He started his own laboratory (Neurology) at WashU in 2010, received tenure in 2015. Around 2011, the lab developed a novel micro-immunoelectrode (MIE) that uses amperompetry to detect rapid changes in A and tau in a mouse brain. The biosensors have an antibody attached to the electrode surface to make it specific to a particular protein. In August 2020, they adapted the format of the electrode to detect SAR-CoV-2. The biosensor can detect virus 20-50 viral particles per milliliter in under a minute. That biosensor is being deployed in a breathalyzer and an indoor air quality monitor. John is a scientific founder of Y2X Life Sciences, the company that has licensed the technology for commercialization.

Abstract
The COVID-19 pandemic has shown the significance of innovative tools for disease diagnostics on the spot. The long turnaround times of generally used diagnostic tools, such as polymerase chain reaction (PCR), have limited the efforts to for getting back to the usual daily life situation. As an alternative diagnostic tool, the rapid test kits such as lateral flow assays were utilized to control the pandemic. However, the accuracy and sensitivity were always found questionable to be compared with PCR performance. Therefore user-friendly, cheap, rapid, accurate, sensitive, and portable sensors still become vital for disease biomarker detection, especially in rural areas for point of care applications. The organic electrochemical transistor (OECT) was used as a biosensor and it translates the binding event into an electrical signal. The gold electrodes were fabricated on a disposable substrate, which is later on functionalized with a uniquely engineered protein construct that specifically binds to the target virus. Owing to the high density of recognition units immobilized on the gate electrode and more importantly to large signal amplification feature of the OECT, the sensor responds to very low concentrations of the protein. However, due to the diffusion-dominated transport, the sensor requires certain time to display a difference the output signal. This incubation step is mostly a main reason of long sample-to-result times and can cause difference among the same measurement, resulting in measurement errors. One of the most suitable way to reduce incubation time and later measurement error is to utilize from the convective forces to transport the target proteins towards to the sensor area. Alternating current electrothermal flow (ACET) was cooperated with an electrochemical biosensor to accelerate the device operation. Using the SARS-CoV-2 spike protein in human saliva and nasal swab as an example target, it is shown that ACET enables protein recognition within only a few minutes of sample exposure, supporting its use in clinical practice. Other alternative techniques with an emphasis on optical biosensors will be also presented in the perspective of validation of electrochemical sensor results and the versatility of the technique.
Biography
Anil Koklu is currently a senior lead engineer in ASELSAN. He completed his B.S. degree in Mechanical Engineering at Istanbul Technical University (ITU) in 2014. He received his M.S. and Ph.D. degrees in Mechanical Engineering from Southern Methodist University (SMU) in 2019. He worked 3 year as a Research Scientist at King Abdullah University of Science and Technology. His background includes iterdiciplinary research program with close collaborations in the fields of microfluidics integrated electrochemical and optical based biosensors.