By taking advantage of the self-polymerization of dopamine on the surface of magnetic nanospheres in weak alkaline Tris-HCl buffer solution, a facile approach was established to fabricate core-shell magnetic molecularly imprinted nanospheres towards hypericin (Fe 3 O 4 @PDA/Hyp NSs), via a surface molecular imprinting technique. The Fe 3 O 4 @PDA/Hyp NSs were characterized by FTIR, TEM, DLS, and BET methods, respectively. The reaction conditions for adsorption capacity and selectivity towards hypericin were optimized, and the Fe 3 O 4 @PDA/Hyp NSs synthesized under the optimized conditions showed a high adsorption capacity (Q = 18.28 mg/g) towards hypericin. The selectivity factors of Fe 3 O 4 @PDA/Hyp NSs were about 1.92 and 3.55 towards protohypericin and emodin, respectively. In addition, the approach established in this work showed good reproducibility for fabrication of Fe 3 O 4 @PDA/Hyp.

Abstract:To fabricate molecularly imprinted polymer nanospheres via click reaction, five different clickable compounds were synthesized and two types of click reactions (azide-alkyne and thiol-yne) were explored. It was found that molecularly imprinted polymer nanospheres could be successfully synthesized via thiol-yne click reaction using 3,5-diethynyl-pyridine (1) as the monomer, tris(3-mercaptopropionate) (tri-thiol, 5) as the crosslinker, and hypericin as the template (MIP-NSHs). The click polymerization completed in merely 4 h to produce the desired MIP-NSHs, which were characterized by FTIR, SEM, DLS, and BET, respectively. The reaction conditions for adsorption capacity and selectivity towards hypericin were optimized, and the MIP-NSHs synthesized under the optimized conditions showed a high adsorption capacity (Q = 6.03 µmol·g −1 ) towards hypericin. The imprinting factors of MIP-NSHs towards hypericin, protohypericin, and emodin were 2.44, 2.88, and 2.10, respectively.