Wei Shuting, Molinelli Alexandra, Mizaikoff Boris
School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA.
Biosens Bioelectron. 2006 Apr 15;21(10):1943-51. doi: 10.1016/j.bios.2005.09.017. Epub 2005 Dec 2.
A one-step precipitation polymerization procedure for the synthesis of molecularly imprinted polymers selective for 17beta-estradiol yielding imprinted micro and nanospheres was developed in this study and compared to templated materials obtained by conventional bulk polymerization. The polymer particles prepared by precipitation polymerization exhibited a regular spherical shape at the micro and nanoscale with a high degree of monodispersity. Moreover, the influence of the polymerization temperature, and the ratio of functional monomer to cross-linker on the size of the obtained particles was investigated. The selectivity of the imprinted micro and nanospheres was evaluated by HPLC analysis and via radioligand binding assays. HPLC separation experiments revealed that the imprinted microspheres provide higher or similar affinity to the template in contrast to imprinted polymers prepared by conventional bulk polymerization or synthesized by multi-step swelling/polymerization methods. The dimensions of the imprinted nanospheres facilitate suspension in solution rendering them ideal for binding assay applications. Results from saturation and displacement assays prove that the imprinted nanospheres exhibit superior specific affinity to the target molecule in contrast to control materials. The binding properties of the nanospheres including binding isotherms and affinity distribution were studied via Freundlich isotherm affinity distribution (FIAD) analysis. Moreover, release experiments show that 70% of rebound 17beta-estradiol was released from the imprinted nanospheres within the first 2 h, while more intimately bound 17beta-estradiol molecules (approx. 16%) were released in the following 42 h. Fitting Brunnauer-Emmet-Teller (BET) multi-point adsorption isotherms to the obtained results indicated that the micro and nanospheres are characterized by a comparatively homogenous and narrow distribution of mesopores in contrast to the corresponding bulk polymers.
本研究开发了一种一步沉淀聚合法，用于合成对17β-雌二醇具有选择性的分子印迹聚合物，得到印迹微球和纳米球，并与通过传统本体聚合法获得的模板材料进行比较。通过沉淀聚合法制备的聚合物颗粒在微米和纳米尺度上呈现规则的球形，具有高度的单分散性。此外，研究了聚合温度以及功能单体与交联剂的比例对所得颗粒尺寸的影响。通过高效液相色谱（HPLC）分析和放射性配体结合试验评估了印迹微球和纳米球的选择性。HPLC分离实验表明，与通过传统本体聚合法制备或通过多步溶胀/聚合法合成的印迹聚合物相比，印迹微球对模板具有更高或相似的亲和力。印迹纳米球的尺寸便于在溶液中悬浮，使其成为结合试验应用的理想选择。饱和和置换试验结果证明，与对照材料相比，印迹纳米球对目标分子表现出优异的特异性亲和力。通过弗伦德利希等温线亲和力分布（FIAD）分析研究了纳米球的结合特性，包括结合等温线和亲和力分布。此外，释放实验表明，70%的反弹17β-雌二醇在最初2小时内从印迹纳米球中释放出来，而在接下来的42小时内释放出更多紧密结合的17β-雌二醇分子（约16%）。将布鲁瑙尔-埃米特-泰勒（BET）多点吸附等温线拟合到所得结果表明，与相应的本体聚合物相比，微球和纳米球的特点是中孔分布相对均匀且狭窄。
