Li Xinxin,Lin Min,Zhang Hongfeng,Ji Wenquan,Shi Yuhan,Qi Zhiyang,Fu Tianwen,Li Qinran,Deng Qiliang
A kind of surface imprinted particles was synthesized to recognize cytochrome c (Cyt c) by a novel strategy combining reversible addition-fragmentation chain transfer (RAFT) radical polymerization and epitope surface imprinting. N-terminal epitope nonapeptide of Cyt c was chosen as the template. The selectivity of these particles for protein recognition was obviously improved due to the selection of epitopes rather than the whole protein as templates and the controllable length of polymer shell chain. After epitope had been modified on the surface of silica, the surface imprinted polymer with controlled imprinted layer was synthesized with monomers and cross-linkers by RAFT radical polymerization strategy. The epitope surface imprinted particles were obtained after the peptide removed and trithioester group destruction by hexylamine. The binding capacity of N-terminal peptide reached 1.88 mg peptide per gram with imprinting factor (IF) as 2.42 while the binding capacity of Cyt c reached 8.89 mg protein per gram with IF as 1.71, which were obviously higher than the IF of the material without RAFT strategy. Moreover, Cyt c could be selectively recognized by the epitope surface imprinted particles even in presence of the competitive proteins with different molecular weight and isoelectric point. The performance of protein recognition remained 90% after five cycles of adsorption and desorption. All these results demonstrated that the epitope surface imprinted particles prepared by RAFT strategy are promising to achieve the protein recognition with higher recognition ability, selectivity and reusability.
Lin Min,Li Xinxin,Zhang Hongfeng,Ji Wenquan,Shi Yuhan,Li Qinran,Zhang Chenxi,Deng Qiliang
Abstract The C-terminal epitope imprinted polymers on the silica were prepared by reversible addition-fragmentation chain transfer (RAFT) strategy with C-terminal nonapeptide of cytochrome c (Cyt c) as the template. 4-cyano-4-(phenylcarbonothioylthio) phetanoic acid was immobilized on the silica as a chain transfer agent to regulate the polymerization of the imprinted layer to enhance the recognition performance of the imprinted materials for the peptide and target protein. Additionally, zinc methacrylate was used as a functional monomer to form the imprinted sites through the synergistic effect of Zn 2+ chelating, hydrogen bonding and electrostatic attraction, which further improved the recognition between polymers and protein. The molecularly imprinted polymers prepared with RAFT strategy show good recognition for the epitope peptide and Cyt c with imprinting factors of 7.96 and 6.17, respectively, which is higher than those prepared without RAFT strategy. Furthermore, the imprinted polymers have a good binding capacity and imprinting factor for Cyt c in multi-proteins selective recognition and have good reusability. The performance of Cyt c recognition in bovine serum by the epitope imprinted polymers was calculated by HPLC and the results demonstrated the well selectivity and potential application for Cyt c recognition in biological sample. Graphical abstract
Magnetic molecularly imprinted polymers (MMIPs) have become a hotspot owing to the dual functions of target recognition and magnetic separation. In this study, the MMIPs were obtained by the surface-initiated reversible addition fragmentation chain transfer (RAFT) polymerization using Sudan I as the template. The resultant MMIPs were characterized by transmission electron microscope, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, vibrating sample magnetometer, and X-ray diffraction. Benefiting from the controlled/living property of the RAFT strategy, the uniform MIP layer was successfully grafted on the surface of RAFT agent-modified Fe 3 O 4 @SiO 2 nanoparticles, favoring the fast mass transfer and rapid binding kinetics. The developed MMIPs were used as the solid-phase extraction sorbents to selectively extract four Sudan dyes (Sudan I, II, III, and IV) from chili powder samples. The recoveries of the spiked samples in chili powder samples ranged from 74.1 to 93.3% with RSD lower than 6.4% and the relative standard uncertainty lower than 0.029. This work provided a good platform for the extraction and removal of Sudan dyes in complicated matrixes and demonstrated a bright future for the application of the well-constructed MMIPs in the field of solid-phase extraction.
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