The high demand for sensitive and selective detection systems resounds from the health, food and environmental sectors. These systems must be able to detect and quantify target molecules, important for assessing the level of contamination in food and environmental samples. Electrochemical sensors are very attractive tools for monitoring the presence of pollutants, as these devices are fast, portable, extremely sensitive and selective towards electroactive species, especially when a bio-recognition element is integrated onto the electrode surface. Electrochemical biosensors are analytical devices that consist of a sensitive biological recognition material targeting an analyte of interest and a transduction element for converting the recognition process into an amperometric, potentiometric or impedimetric signal. A highly competitive topic in developing biosensors is the use of aptamers, also known as ‘artificial antibodies’, as bio-recognition compound. Aptamers (single strand (ss)DNA or RNA) are synthetic oligonucleic acid sequences which can bind to their targets with high affinity and specificity due to their flexibility. Electrochemical sensors with immobilized aptamers as sensing elements are called electrochemical aptasensors. However, a rapid translation of successful aptasensing technologies into a routine assay for environmental monitoring is only at an early stage due to several practical challenges that puts limits on their wide applications. Aptamers cannot bind to smaller toxicants with the high affinity required for most sensing applications. In addition, other problems can occur such as surface biofouling and nonspecific adsorption, leading to false response errors and decreased sensitivity. Moreover, they have to be protected against degradation by nucleases in biological media, and in blood in particular. This presentation reports on new strategies, which were developed and used to achieve efficient electrochemical aptasensing of low molecular weight toxic compounds in the environment. The main goal was identification and improvement of different parameters affecting the quality of the ss DNA aptamer monolayer on the surface of the sensor and subsequent performance of the electrochemical aptasensing platform. In order to accomplish this goal, different innovative strategies of ssDNA-aptamer immobilization/pre-structuring, application of a host matrix, sensor surface pretreatment, and signal amplification methods will be introduced and discussed.
Biography:
Sanaz Pilehvar received her B.S. degree in Applied Chemistry from University of Tabriz, Iran in 2009 and her M.S. degree in Electroanalytical chemistry from Tehran Polytechnic, Iran in 2011. She received the Ph.D. degree in Bioanalytical chemistry from University of Antwerp, Belgium in 2016. Her research interests include miniaturized electrochemical biosensors, biofuel cell for self-powered biosensors, electrocatalysis in wastewater treatment and photo electrochemistry of semiconductors. Her Phd studies has led to the publication of more than 20 scientific papers in high impact factor peer reviewed journals and conferences. She is the recipient of outstanding master’s thesis award from Iranian nanotechnology initiative council in 2010, the Flanders Research Foundation award in 2015 and different awards and prizes from international conferences.
