Sandwich-structured imprinted polymers for colorimetric glycoprotein detection via functionalized CeO2 nanozyme catalysis†

Glycoproteins are crucial in cell signal transduction, adhesion, and the immune system. Abnormal expression of glycoproteins is closely related to severe diseases, including primary liver cancer, breast cancer, and so on. However, detecting glycoproteins with high sensitivity, specificity, and low cost remains challenging due to their low physiological concentration and the complexity of biological samples. In this work, by taking transferrin (TrF) as an example, sandwich-like imprinted polymers were developed by utilizing a functionalized CeO₂ nanozyme as a secondary recognition group and applied in the colorimetric detection of TrF. In this sandwich structure, magnetic molecularly imprinted polymers (MIPs) were synthesized by dopamine polymerization with Fe₃O₄@SiO₂ as a magnetic nucleus, TrF as a template molecule, boronic acid as a functional monomer and dopamine as a cross-linking agent. CeO₂@Au@B(OH)₂ is attached to MIPs as a secondary recognition group through boric acid affinity, constituting a nanozyme. On this basis, the colorimetric detection method of TrF was proposed based on the nanozyme for the selective catalytic oxidation of TMB (3,3′,5,5′-tetramethylbenzidine), which led to a color change with an increase in the concentration of TrF. The established analysis method showed a linear detection range of 10–80 μg mL⁻¹, with a low detection limit of 0.0192 μg mL⁻¹ and a short assay time of 60 min. This method can offer a simple, rapid, and cost-effective approach to detecting disease-related glycoproteins, which may be serum screening agents in the early diagnosis of diseases in non-specialized laboratory infrastructure.