title: High-capacity thermo-responsive magnetic molecularly imprinted polymers for selective extraction of curcuminoids.
abstract: Thermo-responsive magnetic molecularly imprinted polymers (TMMIPs) for selective recognition of curcuminoids with high capacity and selectivity have firstly been developed. The resulting TMMIPs were characterized by TEM, FT-IR, TGA, VSM and UV, which indicated that TMMIPs showed thermo-responsiveness [lower critical solution temperature (LCST) at 33.71°C] and rapid magnetic separation (5s). The polymerization, adsorption and release conditions were optimized in detail to obtain the highest binding capacity, selectivity and release ratio. We found that the adopted thermo-responsive monomer [N-isopropylacrylamide (NIPAm)] could be considered not only as inert polymer backbone for thermo-responsiveness but also as functional co-monomers combination with basic monomer (4-VP) for more specific binding sites when ethanol was added in binding solution. The maximum adsorption capacity with highest selectivity of curcumin was 440.3μg/g (1.93 times that on MMIPs with no thermosensitivity) at 45°C (above LCST) in 20% (v/v) ethanol solution on shrunk TMMIPs, and the maximum release proportion was about 98% at 20°C (below LCST) in methanol-acetic acid (9/1, v/v) solution on swelled TMMIPs. The adsorption process between curcumin and TMMIPs followed Langumuir adsorption isotherm and pseudo-first-order reaction kinetics. The prepared TMMIPs also showed high reproducibility (RSD<6% for batch-to-batch evaluation) and stability (only 7% decrease after five cycles). Subsequently, the TMMIPs were successfully applied for selective extraction of curcuminoids from complex natural product, Curcuma longa.
authors.affiliation: School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China.
authors.forename: Qingping
authors.initials: Q
authors.lastname: You
authors.affiliation: School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China.
authors.forename: Yuping
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory for Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao SAR, China.
authors.forename: Qingwen
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China.
authors.forename: Junfang
authors.initials: J
authors.lastname: Guo
authors.affiliation: Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China.
authors.forename: Weihua
authors.initials: W
authors.lastname: Huang
authors.affiliation: School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China; Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China. Electronic address: shuyshi@gmail.com.
authors.forename: Shuyun
authors.initials: S
authors.lastname: Shi
authors.affiliation: School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China.
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Chen
mesh_terms: D001565:Benzoates / Q000737:chemistry / Q000302:isolation & purification*; D030024:Curcuma / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D060526:Magnetic Fields; D046529:Microscopy, Electron, Transmission; D054802:Molecular Imprinting / Q000379:methods*; D011108:Polymers / Q000737:chemistry*; D015203:Reproducibility of Results; D013696:Temperature
chemical_list: D001565:Benzoates; D011108:Polymers
keywords: Curcuminoid; Magnetic separation; Molecularly imprinted polymers; Natural product; Thermo-responsiveness