Dai Mengzhen, Huang Ting, Chao Long, Xie Qingji, Tan Yueming, Chen Chao, Meng Wenhua
Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China.
Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, PR China.
Talanta. 2016;149:117-123. doi: 10.1016/j.talanta.2015.11.047. Epub 2015 Dec 1.
Horseradish peroxidase (HRP)-catalyzed polymerization of L-DOPA (vs. dopamine) in the presence of H2O2 (and uricase (UOx)) was exploited to immobilize mono-/bi-enzymes for hydroquinone-mediated amperometric biosensing of H2O2 and uric acid (UA). The relevant polymeric biocomposites (PBCs) were prepared in phosphate buffer solution containing HRP and L-DOPA (or plus UOx) after adding H2O2. The mono-/bi-enzyme amperometric biosensors were prepared simply by casting some of the PBCs on Au-plated Au (Au(plate)/Au) electrodes, followed by coating with an outer-layer chitosan (CS) film for each. UV-vis spectrophotometry, scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy were used for film characterization and/or process monitoring. The HRP immobilized by enzyme catalysis well preserved its bioactivity, as confirmed by UV-vis spectrophotometry. Under optimized conditions, the monoenzyme CS/HRP-poly(L-DOPA) (PD)/Au(plate)/Au electrode potentiostated at -0.1V responded linearly to H2O2 concentration from 0.001 to 1.25mM with a sensitivity of 700μA mM(-1)cm(-2) and a limit of detection (LOD) of 0.1μM, and the bienzyme CS/UOx-HRP-PD/Au(plate)/Au electrode at -0.1V responded linearly to UA concentration from 0.001 to 0.4mM with a sensitivity of 349μA mM(-1)cm(-2) and a LOD of 0.1μM. The mono-/bi-enzyme biosensors based on biosynthesized PD performed better than many reported analogues and those based on similarly biosynthesized polydopamine.
利用辣根过氧化物酶（HRP）在过氧化氢（以及尿酸酶（UOx））存在的情况下催化L-多巴（相对于多巴胺）的聚合反应，将单酶/双酶固定化，用于对苯二酚介导的过氧化氢和尿酸（UA）的安培生物传感。在加入过氧化氢后，在含有HRP和L-多巴（或加UOx）的磷酸盐缓冲溶液中制备相关的聚合物生物复合材料（PBCs）。单酶/双酶安培生物传感器的制备方法很简单，即将一些PBCs浇铸在镀金的金（Au(plate)/Au）电极上，然后分别用外层壳聚糖（CS）膜进行包覆。采用紫外-可见分光光度法、扫描电子显微镜、循环伏安法和电化学阻抗谱对薄膜进行表征和/或过程监测。通过紫外-可见分光光度法证实，通过酶催化固定化的HRP很好地保留了其生物活性。在优化条件下，在-0.1V电位下的单酶CS/HRP-聚（L-多巴）（PD）/Au(plate)/Au电极对过氧化氢浓度在0.001至1.25mM范围内呈线性响应，灵敏度为700μA mM⁻¹ cm⁻²，检测限（LOD）为0.1μM；在-0.1V电位下的双酶CS/UOx-HRP-PD/Au(plate)/Au电极对尿酸浓度在0.001至0.4mM范围内呈线性响应，灵敏度为349μA mM⁻¹ cm⁻²，LOD为0.1μM。基于生物合成的PD的单酶/双酶生物传感器的性能优于许多已报道的类似物以及基于类似生物合成的聚多巴胺的生物传感器。
