Abstract An amperometric uric acid (UA) biosensor was developed by immobilizing uricase on porous cryogel (cry) platform of graphene-incorporated chitosan (Chi) on top of a Prussian blue layer (PB) electrodeposited on a screen-printed carbon electrode (Uricase/Chi-Gr cry/PB/SPCE). Amperometric detection of UA catalyzed by uricase was based on the change in cathodic current of PB at a potential of 0.00 V in a flow injection system. The UA biosensor showed a linear range between 0.0025 and 0.40 mmol L−1 with a detection limit of 2.5 µmol L−1 (S/N = 3). In addition, the Uricase/Chi-Gr cry/PB/SPCE provided an excellent stability that enabled reuse up to 175 times (RSD of 3.7%) and a good electrode-to-electrode repeatability (RSDs of 0.53–2.7%, n = 6). A Michaelis-Menten constant ( K M a p p ) of 0.23 mmol L−1 indicated the excellent affinity of the immobilized uricase toward UA. The modified electrode showed no effect from the common interferences in human serum samples. When applied to measure UA in human serum samples, the developed UA biosensor achieved recoveries ranging from 98 ± 2 to 102 ± 5% and the results obtained were in good agreement with enzymatic colorimetric analysis (P > 0.05).

中文翻译：

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基于普鲁士蓝涂层和壳聚糖-石墨烯复合冷冻凝胶修饰的丝网印刷电极的尿酸酶生物传感器

摘要 通过在丝网印刷碳电极 (Uricase/ Chi-Gr 哭声/PB/SPCE）。尿酸酶催化 UA 的电流检测是基于流动注射系统中 0.00 V 电位下 PB 阴极电流的变化。UA 生物传感器显示线性范围介于 0.0025 和 0.40 mmol L-1 之间，检测限为 2.5 µmol L-1 (S/N = 3)。此外，尿酸酶/Chi-Gr cry/PB/SPCE 具有出色的稳定性，可重复使用多达 175 次（RSD 为 3.7%）和良好的电极间重复性（RSD 为 0.53–2.7%，n = 6). Michaelis-Menten 常数 (KM app) 为 0。23 mmol L-1 表明固定化尿酸酶对 UA 具有极好的亲和力。修改后的电极不会受到人血清样品中常见干扰的影响。当应用于测量人血清样品中的 UA 时，开发的 UA 生物传感器实现了 98 ± 2 至 102 ± 5% 的回收率，获得的结果与酶比色分析非常吻合（P > 0.05）。