Analytical Division, Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 221005, India.
Mater Sci Eng C Mater Biol Appl. 2013 Oct;33(7):4071-80. doi: 10.1016/j.msec.2013.05.052. Epub 2013 Jun 4.
A new molecularly imprinted polymer-matrix (titanium dioxide nanoparticle/multiwalled carbon nanotubes) nanocomposite was developed for the modification of pencil graphite electrode as an enantioselective sensing probe for aspartic acid isomers, prevalent at ultra trace level in aqueous and real samples. The nanocomposite having many shape complementary cavities was synthesized adopting surface initiated-activators regenerated by electron transfer for atom transfer radical polymerization. The proposed sensor has high stability, nanocomposite uniformity, good reproducibility, and enhanced electrocatalytic activity to respond oxidative peak current of L-aspartic acid quantitatively by differential pulse anodic stripping voltammetry, without any cross-reactivity in real samples. Under the optimized operating conditions, the L-aspartic acid imprinted modified electrode showed a wide linear response for L-aspartic acid within the concentration range 9.98-532.72 ng mL(-1), with the minimum detection limit of 1.73-1.79 ng mL(-1) (S/N=3) in aqueous and real samples. Almost similar stringent limit (1.79 ng mL(-1)) was obtained with cerebrospinal fluid which is typical for the primitive diagnosis of neurological disorders, caused by an acute depletion of L-aspartic acid biomarker, in clinical settings.
一种新型的分子印迹聚合物-基质（二氧化钛纳米粒子/多壁碳纳米管）纳米复合材料被开发出来，用于修饰铅笔石墨电极，作为一种对天门冬氨酸异构体具有手性选择性传感探针，这些异构体在水相和实际样品中以痕量水平存在。该纳米复合材料具有许多形状互补的空腔，采用表面引发-电子转移再生引发剂原子转移自由基聚合合成。该传感器具有高稳定性、纳米复合材料均匀性、良好的重现性和增强的电催化活性，通过差分脉冲阳极溶出伏安法定量响应 L-天门冬氨酸的氧化峰电流，在实际样品中没有任何交叉反应。在优化的操作条件下，L-天门冬氨酸印迹修饰电极在 9.98-532.72ng/mL 浓度范围内对 L-天门冬氨酸呈现宽线性响应，在水相和实际样品中的检测限低至 1.73-1.79ng/mL（S/N=3）。在临床环境中，脑脊液中获得了几乎相同严格的限制（1.79ng/mL），这是由 L-天门冬氨酸生物标志物的急性消耗引起的神经紊乱的原始诊断的典型特征。
