Preparation and Binding Evaluation of Histamine-Imprinted Microspheres via Conventional Thermal and RAFT-Mediated Free-Radical Polymerization

Elevated histamine (HTM) levels are closely linked to food poisoning as well as to pathophysiological allergic diseases. In this study, HTM-imprinted, solution-processable microspheres were prepared via high-dilution conventional thermal polymerization (CTP) and controlled radical polymerization (CRP) using ethylene glycol dimethacrylate (80 or 90 wt %) and methacrylic acid at 60 °C in acetonitrile and evaluated as recognition materials for sensing applications. The polymers were selective to HTM in binding studies, cross-rebinding, and competitive binding assays against the HTM analogues histidine, imidazole, and tryptamine. The selective binding capacity was significantly higher with CTP-80 (on the basis of mass: 21.0 μmol/g and surface area: 8.08 × 10^–2 μmol/m²) than that with both CTP-90 (8.47 μmol/g, 4.49 × 10^–2 μmol/m²) and CRP-80 (9.00 μmol/g, 1.19 × 10^–2 μmol/m²).