Advancing Biosensor Technology with Photochemical Immobilization Technique-Prof. R. Velotta-Physics Department – University of Naples Federico II
Abstract: Biosensors are devices where a biological sensitive element (bio-receptor) is connected to or integrated with a transducer that produces a digital electronic signal proportional to the concentration of the chemical substance (analyte or antigen) to detect. Therefore, surface functionalization is a crucial issue in biosensing since it affects both the sensitivity and the specificity of the resulting device. In view of its unique properties, gold is one of the most used materials, finding application in a number of transducers (Quartz Crystal Microbalance and Surface Plasmon Resonance among others); thus, several approaches are proposed to bind appropriate bioreceptors to gold, all of them sharing quite complex chemistry.
As an alternative method, the Photochemical Immobilization Technique (PIT) offers a simple and effective way to tether antibodies upright to gold electrodes so that their variable part (i.e., the antibody region capable of recognizing the antigen) is exposed to the solution. This technique has been successfully demonstrated for contaminants of environmental interest as well as for toxic or undesired compounds in food (e.g., patulin and gliadin). The extension of PIT to electrochemical- and optics-based devices has been proven effective; in particular, PIT has been successfully used to functionalize nanostructured gold surfaces, realizing an immunosensor capable of detecting immunoglobulins in human urine or PSA in blood through the so-called plasmonic-enhanced fluorescence.
In this talk, PIT and its application to several transducers will be described, with emphasis on the detection of analytes of interest in food safety, environmental monitoring, and medical diagnostics.
Biography: Raffaele Velotta graduated (M.Sc.) at University of Naples in 1987 and earned his Ph.D. in physics from the same university in 1992 with a thesis on the plasma effects in atomic physics experiment. In 2000 he visited the Blackett Laboratory at Imperial College joining the laser physics group to investigate high-order harmonic generation from aligned molecules. In 2015 he was appointed full professor of physics at University of Naples “Federico II”. For several years his research concerned the ultrashort laser pulses interaction with atoms and molecules. His current research interests focus on biosensing with particular emphasis on immunosensors based on nanoparticles and nanostructured surfaces for applications to food-safety, environmental monitoring and medical diagnostics.