You Qingping, Zhang Yuping, Zhang Qingwen, Guo Junfang, Huang Weihua, Shi Shuyun, Chen Xiaoqin
School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China.
State Key Laboratory for Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao SAR, China.
J Chromatogr A. 2014 Aug 8;1354:1-8. doi: 10.1016/j.chroma.2014.05.040. Epub 2014 May 23.
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.
首次开发了用于高容量和选择性地选择性识别姜黄素类化合物的热响应磁性分子印迹聚合物（TMMIPs）。通过透射电子显微镜（TEM）、傅里叶变换红外光谱（FT-IR）、热重分析（TGA）、振动样品磁强计（VSM）和紫外可见光谱（UV）对所得的TMMIPs进行了表征，结果表明TMMIPs具有热响应性[在33.71°C时的下临界溶液温度（LCST）]和快速磁分离性能（5秒）。详细优化了聚合、吸附和释放条件，以获得最高的结合容量、选择性和释放率。我们发现，所采用的热响应单体[N-异丙基丙烯酰胺（NIPAm）]不仅可以被视为具有热响应性的惰性聚合物主链，而且当在结合溶液中加入乙醇时，还可以作为与碱性单体（4-乙烯基吡啶，4-VP）组合的功能性共聚单体，以形成更多特异性结合位点。在45°C（高于LCST）的20%（v/v）乙醇溶液中，收缩态的TMMIPs对姜黄素的最大吸附容量和最高选择性为440.3μg/g（是对无热敏感性的分子印迹聚合物（MMIPs）的1.93倍），在20°C（低于LCST）的甲醇-乙酸（9/1，v/v）溶液中，溶胀态的TMMIPs上姜黄素的最大释放比例约为98%。姜黄素与TMMIPs之间的吸附过程遵循朗缪尔吸附等温线和准一级反应动力学。所制备的TMMIPs还表现出高重现性（批次间评估的相对标准偏差RSD<6%）和稳定性（五个循环后仅降低7%）。随后，TMMIPs成功应用于从复杂天然产物姜黄中选择性提取姜黄素类化合物。
