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. 2017 Apr 7;9(4):135.
doi: 10.3390/polym9040135.

A Facile Approach for Fabrication of Core-Shell Magnetic Molecularly Imprinted Nanospheres towards Hypericin

Wenxia Cheng  1 , Fengfeng Fan  2 , Ying Zhang  3 , Zhichao Pei  4 , Wenji Wang  5 , Yuxin Pei  6
Affiliations

A Facile Approach for Fabrication of Core-Shell Magnetic Molecularly Imprinted Nanospheres towards Hypericin

Wenxia Cheng et al. Polymers (Basel). .

Abstract

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 (Fe₃O₄@PDA/Hyp NSs), via a surface molecular imprinting technique. The Fe₃O₄@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 Fe₃O₄@PDA/Hyp NSs synthesized under the optimized conditions showed a high adsorption capacity (Q = 18.28 mg/g) towards hypericin. The selectivity factors of Fe₃O₄@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 Fe₃O₄@PDA/Hyp.

Keywords: core-shell; dopamine; hypericin; magnetic nanospheres; surface molecular imprinting.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Scheme 1
Scheme 1
(A) Illustration of noncovalent bonding of template, hypericin with the functional monomer, dopamine: hydrogen bonding and π−π interaction; (B) Schematic illustration of fabricating Fe3O4@PDA/Hyp.
Figure 1
Figure 1
FTIR spectra of Fe3O4@PDA/Hyp, Fe3O4@PDA, MNSs, Hypericin and polydopamine (PDA).
Figure 2
Figure 2
TEM images of the nanospheres (NSs) prepared: (a) Fe3O4@PDA NSs; (b) Fe3O4@PDA/Hyp NSs; (c,d) are the enlarged images corresponding to (a,b), respectively. Scale bar: 200 nm.
Figure 3
Figure 3
Effect of concentration of dopamine on specific absorption capacity (Qs).
Figure 4
Figure 4
Effect of amount of hypericin (% of dopamine in mole) on specific absorption capacity (Qs).
Figure 5
Figure 5
Effect of the ratio of acetone to Tris-HCl buffer (v/v) on specific adsorption capacity (Qs).
Figure 6
Figure 6
Dynamic adsorption of hypericin on Fe3O4@PDA/Hyp and Fe3O4@PDA NSs.
Figure 7
Figure 7
(a) The adsorption isotherm of Fe3O4@PDA/Hyp NSs towards hypericin; (b) The fitting plot of the adsorption isotherm of Fe3O4@PDA/Hyp NSs towards hypericin by Langmuir isotherm.
Figure 8
Figure 8
(a) The chemical structures of hypericin, protohypericin, and emodin; (b) Selective bindings of Fe3O4@PDA/Hyp (black) and Fe3O4@PDA (red) NSs toward to hypericin, protohypericin, and emodin, respectively.
Figure 9
Figure 9
Reproducibility study of the approach for fabrication of Fe3O4@PDA/Hyp NSs under the optimized conditions.
Figure 10
Figure 10
HPLC chromatograms. (a) the herb extract; (b) the mixture of the extract, hypericin and protohypericin before adsorption; (c) the supernatant after the adsorption of Fe3O4@PDA NSs; (d) the supernatant after the adsorption of Fe3O4@PDA/Hyp NSs.
See this image and copyright information in PMC

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