Eugenia Fagadar-Cosma
Institute of Chemistry Timisoara of Romanian Academy, Romania
Title: Sensors based on biomimetic porphyrin derivatives & their hybrid combinations with photonic nanoparticles
Biography
Biography: Eugenia Fagadar-Cosma
Abstract
Most synthetic porphyrins are hydrophobic π-conjugated macrocycles and as a consequence organic building blocks for supramolecular chemistry, providing in this way the required optoelectronic and morphological properties for a plethora of novel sensors. Besides, porphyrins possess huge capacity for chemical modifications by peripheral substitution and by using them in hybrid combination with photonic, electronic and magnetic compounds. Wide band absorption hybrid materials were prepared from different A3B porhyrins and cobalt, manganese and zinc metalloporphyrins and silver or gold nanoparticles with the purpose to develop optical and electrochemical detection of hydrogen peroxide or other compounds showing potential in early medical diagnosis. The synthesized materials were characterized by UV-vis, fluorescence, FT-IR, AFM, SEM TEM and CV. STEM investigation of the porphyrin-gold hybrids revealed some dendritic structures produced mainly by porphyrin H- and J-type helicoidal self-aggregation due to their interaction with gold nanoparticles. Layer-by-layer assembly of gold colloid nanoparticles and cobalt porphyrins on GC electrodes generated electroactive thin films capable to electrochemically detect minute quantities of H2O2 that are relevant for early diagnosis in medicine. The Co-porphyrin-gold hybrid was exposed to increased amounts of H2O2 and the changes of the absorption spectra were monitored by UV-vis spectroscopy, proving the same quality of sensing capacity.