Preparation of new molecularly imprinted nanosensor for cholic acid determination

Molecular imprinted polymers (MIPs) as a recognition element for sensors are increasingly of interest and MIP-nanoparticles have started to appear in the literature. In this study, we have proposed a novel thiol ligand-capping method with polymerizable methacryloylamido-cysteine (MAC) attached to gold nanoparticles, reminiscent of a self-assembled monolayer and have reconstructed surface shell by synthetic host polymers based on molecular imprinting method for recognition. In this method, methacryloylamidohistidine-Pt(II) [MAH-Pt(II)] has used as a new metal-chelating monomer via metal coordination–chelation interactions and cholic acid. Nanoshell sensors with templates give a cavity that is selective for cholic acid. The cholic acid can simultaneously chelate to Pt(II) metal ion and fit into the shape-selective cavity. Thus, the interaction between Pt(II) ion and free coordination spheres has an effect on the binding ability of the gold nanoparticles nanosensor. The binding affinity of the cholic acid imprinted nanoparticles has investigated by using the Langmuir and Scatchard methods and determined affinity constant (Kaffinity) were found as 1.48 × 104 mol L−1 and 6.59 × 106 mol L−1, respectively. At the last step of this procedure, cholic acid level in blood serum and urine which belong to healthy people was determined by the prepared Au nanosensor.