Molecularly imprinted polymers based on polydopamine: Assessment of non-specific adsorption

During the past ten years, about 30 papers have been published on the use of polydopamine (PDA) for the preparation of molecularly imprinted polymers (MIPs). This promising polymer (PDA) still faces some challenges. The present paper reports for the first time a re-examination study of MIPs based on PDA focusing on the template removal step and its effect on the non-specific adsorption. Three materials were prepared and characterized including magnetic MIPs (magMIPs), magnetic non-imprinted polymers washed (magNIPs-treated) in the same manner as the magMIPs, and magnetic NIPs without washing (magNIPs-untreated). Bovine hemoglobin (BHb), dopamine, and a mixture solution of acetic acid and sodium dodecyl sulfate were used as template, monomer, and washing solution, respectively. The adsorption evaluations of these materials showed that both magMIPs and magNIPs-treated exhibited higher binding capacities compared to magNIPs-untreated suggesting that the high difference between MIPs and NIPs based on PDA observed in the literature is not due to the imprinted cavities but due to the removal step applied to MIPs. The washing solution could rupture the cavities and activate the surface of PDA leading to non-specific adsorption. The proposed investigation was further enlarged for other templates/washing solutions and similar results were obtained.