基于葡聚糖自组装胶体粒子的分子印迹传感器的制备及电化学性能

Fabrication and Electrochemical Performance of MIP Sensor Based on Dextran Self-assembly Colloids Nanoparticles

首先,以光敏小分子肉桂酸(CINN)为疏水基元,通过酯化反应对葡聚糖(Dex)进行疏水改性,制备双亲性大分子Dex-CINN;然后,利用选择性溶剂法诱导Dex-CINN与模板分子葡萄糖(Glu)共组装,制备分子印迹胶体粒子(MINPs)。通过红外光谱(FT-IR)和核磁共振氢谱(1 HNMR)确定Dex-CINN的化学结构及改性率。利用Zeta电位及纳米粒度仪和透射电子电镜(TEM)对MINPs的粒径、电位及形貌进行表征。利用滴涂或电泳沉积的方法使MINPs在电极表面二次组装构建MINPs涂层,通过光交联固定涂层结构,再洗脱除去模板分子后得到分子印迹传感涂层。通过扫描电子显微镜(SEM)对两种分子印迹传感涂层的形貌进行表征,并进一步利用循环伏安法(CV)、差分脉冲溶出伏安法(DPSV)对比研究两种分子印迹传感涂层的分析检测性能。研究结果表明:通过滴涂或电泳沉积的方法均能在电极表面制备分子印迹传感涂层;相比于滴涂法,电泳沉积法所制备的分子印迹传感涂层连续均匀,所形成的传感器对Glu具有更好的响应性以及识别能力,检测下限更低。

By using photo-sensitive molecule cinnamic acid as hydrophobic moiety,amphiphilic macromolecule cinnamic acid modified dextran(Dex-CINN)was prepared through the esterification reaction.The structure and substitution degree of Dex-CINN were characterized by Fourier Transform Infrared spectroscopy(FT-IR)and Hydrogen Nuclear Magnetic Resonance(1H-NMR).The obtained Dex-CINN and template molecule-glucose(Glu)were co-assembled in selective solvent to form molecularly imprinted nanoparticles(MINPs).The size,morphology and Zeta potential of the MINPs were studied by Zeta potential and particle size analyzer and Transmission Electron Microscopy(TEM).The MINPs were first deposited on the surface of the electrode by drop-coating or electrodeposition technique to prepare the MINPs coatings and then followed by UV radiation.After removing the template molecules by extraction,the imprinted MINPs sensor coating were obtained.The morphology of the two kinds of MINPs sensor coatings was studied by Scanning Electron Microscopy(SEM),and their electrochemical performances were evaluated by Cyclic Voltammetry(CV)and Differential Pulse Stripping Voltammetry(DPSV).The results showed that using drop-coating or electrodeposition technique could prepare MINPs sensor coating on the surface of electrode.Compared to the drop-cast coating,the electrodeposition MINPs sensor coating showed good response,selectivity towards glucose and lower detection limit.