基于ZnO纳米棒液相自组装固定血红蛋白及其直接电化学传感器

ZnO-nanorods-based self-assembly in liquid phase for immobilization of hemoglobin and direct electrochemistry sensor

自组装方法制备纳米生物传感器时,常利用聚电解质(如PDDA,poly(diallyl-dimethyl ammonium chloride))与纳米材料和酶的相互作用。但是聚电解质易导致纳米材料团聚,或损害酶的活性,且操作过程较复杂,制备重现性不理想。该工作,利用纳米Zn O与血红蛋白(Hb)等电点差异,直接在纳米材料分散液进行酶混合组装,然后再通过自组装,固定到玻碳电极表面,从而实现了Hb与电极间的直接电子传递。利用紫外吸收光谱(UV-vis)、透射电子显微镜(TEM)及循环伏安等方法对制备过程进行了表征。修饰电极测定H2O2溶液的线性范围是1.06×10-6~7.82×10-3mol/L,检测限是8.86×10-7 mol/L(S/N=3)。相同实验条件下,制备电极对相同浓度H2O2的响应电流的相对标准偏差(R.S.D)在1.9%左右,表明该方法制备的生物传感器制备过程简单、有好的稳定性和重现性。

Self-assembly method could be used to synthesize nanomaterial-based biosensor by the help of polyelectrolyte such as poly（diallyldimethyl ammonium chloride）（PDDA）. However, polyelectrolyte resulted in severe aggregation of nanomaterials or damaging the bioactivity of hemoglobin（Hb）. In addition, the process of preparation was relatively complicate and poor reproducibility. In this work, we developed a simpler method that the ZnO NPs sufficiently bound with Hb, taking advantage of the great difference of isoelectric point between ZnO NPs and Hb, and then self-assemble method was used to modify them on the cleaned glassy carbon electrode（GCE）. The direct electron transfer of Hb was realized on the as-prepared electrode. UV-vis Spectrophotometer, TEM and cyclic voltammetry were used to characterize the synthesis process of biosensor. The responses of H2O2 were linearly proportional to the concentration from 1.06×10-6~7.82×10-3mol/L with a detection limit of 8.86×10-7mol/L（S/N=3）. R.S.D was about l.9% for as-prepared electrodes in 0.15 mmol/L H2O2 in 0.05 mol/L PBS（p H7.0）. This biosensor exhibited the facile-made, good reproducibility and stability.