Synthesis and Characterization of ZnO/4, 5-imidazoledicarboxylic acid Composite and Its Application for Hemoglobin Determination

Petaloid-shaped ZnO grafted with 4,5-imidazoledicarboxylic acid was proposed as a composite to entrap Hemoglobin molecules through the synergistic effect of covalent bonding and adjacent complexation between the hetero-atoms of the imidazolyl ring and the heme sites in Hemoglobin. The morphology, structural features, and physiochemical properties of the composite with Hemoglobin anchoring were investigated by photography, spectroscopy, and electrochemical methods, as well as the mechanism of charge shuttle of the heme protein into the composite and the dynamics of enzymaticcatalysis. Experimental results revealed that intricate interactions between components of the complex and the integrated Hemoglobin molecules alter the mechanism of charge shuttle between cofactors in the enzyme and the conductive matrix with partial heme sites in coordination with the imidazolyl ring as an intra-molecular electron relay. Such interactions are also responsible for the process of substrate binding for the cofactors in the redox protein. The rapid kinetics of heterogeneous charge convection is found to be 89.0 s(-1) with a unique pattern of two electrons per proton. This interactions would also lead to a lower affinity to hydrogen peroxide (893.0 mu M), a high detection limit (0.9 mM), inferior sensitivity (4.5 X 10(-5) A.L.mol(-1)) and moderate kinetics of substrate attachment and transformation (1.9 x10(6) and 29.8 s(-1)).