Preparation of an epitope-imprinted polymer with antibody-like selectivity for beta2-microglobulin and application in...

Molecularly imprinted polymers (MIPs) for protein recognition have great application potential in the biological analysis. However, preparation of protein imprinted polymer is still facing challenge. Beta2-microglobulin (β₂m) is a protein biomarker that can be used in diagnosis of different diseases. In this research, a novel MIP with ability of β₂m recognition has been developed by epitope and surface-confined imprinting approaches. A peptide with sequence of MIQRTPKIQ was selected as template. A strategy of combination of hierarchical imprinting and template immobilization was employed in the β₂m-MIP synthesis. Imprinted binding sites with open-entrance have been created that have good accessibility for β₂m and facilitated fast reversible binding kinetics. The experimental results demonstrated that the MIP has good selectivity. It can differentiate the template from peptide with different sequence and distinguish the β₂m from other proteins with similar size and pI values. After binding property study of the β₂m-MIP, a method of β₂m determination in serum was established in which β₂m was on-line extracted by MIP and analyzed by HPLC process. The recoveries for spiked serum was ≥83% with RSD <1.1%, indicating that the method has good accuracy and precisions. The LOD and LOQ were 0.058 and 0.195mgL^-1 respectively, which meet the requirements of the β₂m analysis. The successful application of the β₂m-MIP demonstrated that β₂m has reversible binding on the MIP with a kinetics that can meet the requirements of the HPLC analysis. It also indicated that the β₂m-MIP has good mechanical strength and reusability that can be applied reliably in the practical analysis. As a synthetic antibody, β₂m-MIP is advantageous compared to the biological molecules.