Michael Müller has completed his Diploma in Biology from Saarland University. After working as a researcher at Korea Institute of Science and Technology, Europe, he is currently doing his PhD degree there.
On this poster, we present an amperometric Cytochrome P450 3A4 (CYP3A4) Biosensor. Human hepatic Cytochrome P450s are responsible for the metabolism of the major part of xenobiotics and, among those, CYP3A4 shows the largest substrate range. This makes this enzyme an interesting target for research in many fields and is a standard test object in drug discovery. To connect the enzyme efficiently to the gold electrode PAMAM, dendrimers of generation 4 have been used that were futher modified with sub nanometer gold particles forming organic/inorganic nanocomposites. The biosensor itself was constructed by using a layer-by-layer assembly method where discrete monolayers of the respected compounds were immobilized in a sequential way due to electrostatic interactions between charged moieties. Assembly of the individual layers was monitored by QCM and FTIR spectroscopy and surface morphologies were observed by AFM. A highly reproducible assembly could be established showing less than 10% variability and in good agreement with theoretically established values for compound monolayer formation. To test the applicability of the CYP3A4 biosensor, cyclic voltammetry (CV) was used to establish electron transfer rate ks as well as the amount of electroactive surface-constraint enzyme. Furthermore, CV was used to detect CYP3A4 substrate caffeine to ascertain detection limit (5µM) and linear range (25-100µM).
Mahnaz M Abdi received her PhD in Material Chemistry from Universiti Putra Malaysia, 2010. She was with Institute of Tropical Forestry and Forest Products, UPM as a Post-doctoral fellow and continued her career as a researcher at the Luleå University of Technology (LTU), Lulea, Sweden. She currently works as senior lecturer/research associate at Universiti Putra Malaysia. Her research focused on nanocomposite materials from conducting polymers/biopolymers and their application in sensors, biosensors, and corrosion protection.
The nanocomposite of Polyaniline/ Cellulose nanocrystal (PANI/CNC) was synthesized via in situ chemical polymerization of aniline in the presence of CNC using ammonium peroxydisulfate (APS) as the oxidant. SEM images showed nanostructure of composite with no phase separation revealed homogenous polymerization of monomer in the presence of cellulose nanowhiskers. Aggregation of PANI particles was observed with increasing aniline concentration. The formation of PANI/CNC nanocomposite on SPE electrode followed by the deposition of a thin layer of ion liquid (IL), [BMIM][Cl], film have combined the unique properties of the individual materials and showed synergy effect of CNC/IL on electrocatalytic properties of nanocomposite for electrochemical biosensor application. The higher anodic/cathodi current for PANI/CNC/IL/SPE modified electrode compare to PANI/SPE electrode showed important rule of CNC and IL in accelerating the electron transfer between polymer and the electrode. Application of PANI/CNC nanocomposite modified electrode for cholesterol detection was investigated.