Recognition of human hemoglobin with macromolecularly imprinted polymeric nanoparticles using non-covalent interactions

Hemoglobin (Hb) is the most abundant protein in the blood. It is vital for the living as oxygen carriers. Some of the very pure Hb-containing biological fluids are currently under clinical trial. However, the removal and purification of Hb from the blood are quite difficult, especially when it is at a low concentration level. In this study, the molecularly imprinted polymeric nanoparticles (MIPNs) were prepared using N-methacryloyl-histidine methyl ester (MAH) by mini-emulsion polymerization technique for specific binding of human hemoglobin (HHb). MIPNs in monosize form have a size of 152 +/- 4 nm. They also have a high binding capacity (32.33 mg/g) of HHb. MIPNs retain 84% of the re-binding capacity for HHb after 10 cycles. The nanoparticles have 16 and 5 times higher binding capacity of HHb, respectively, in the presence of bovine serum albumin and lysozyme. Thanks to their high binding capacity and selectivity, MIPNs will allow them to be detected selectively for different target molecules. According to molecular docking, the main binding forces depend on hydrogen bonds and Van der Waals forces in the interaction within 5 angstrom around MAH molecule are observed through the amino acid residues of HHb at beta 1 and beta 2 subunit. The statistical mechanical analysis of docking showed that the free energy (Delta G) is -2732.14 kcal/mol, which indicates the interaction between MAH and HHb is energetically favorable at 298.15 degrees K.