Abstract We describe the amplification of amperometric l -lysine biosensor using l -lysine oxidase nanoparticles (LOxNPs) and graphene oxide nanoparticles (GrONPs) immobilized onto pencil graphite electrode (PGE). LOxNPs and GrONPs were characterized by UV spectroscopy and transmission electron microscopy (TEM). The working electrode (LOxNPs/GrONPs/PGE) was studied by scanning electron microscopy (SEM) and cyclic voltammetry at different stages of its construction. The biosensor showed optimum current at 0.7 V, pH 6.5, 35 °C, a detection limit of 0.01 μM, response time as 3.95 s and a wider linear range 0.01–1000 μM. The analytical recovery of added lysine in sera was 97 %. The within assay and between batch coefficients of variation for the biosensor were 0.068 and 0.074 % respectively. The biosensor measured l -lysine levels in sera of healthy adults and human immunodeficiency virus (HIV) patients. The biosensor exhibited good correlation with standard spectrophotometric method (R2 = 0.989). The biosensor lost 35 % of its original activity after its regular uses for a period of 180 days, while being stored dry at 4 °C.

中文翻译：

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用 L-赖氨酸氧化酶纳米颗粒和氧化石墨烯纳米颗粒放大的安培 L-赖氨酸测定生物传感器

摘要 我们描述了使用固定在铅笔石墨电极 (PGE) 上的 l - 赖氨酸氧化酶纳米粒子 (LOxNPs) 和氧化石墨烯纳米粒子 (GrONPs) 来放大安培 l - 赖氨酸生物传感器。LOxNPs 和 GrONPs 通过紫外光谱和透射电子显微镜 (TEM) 进行表征。通过扫描电子显微镜 (SEM) 和循环伏安法在其构建的不同阶段研究工作电极 (LOxNPs/GrONPs/PGE)。该生物传感器在 0.7 V、pH 6.5、35 °C 下显示出最佳电流，检测限为 0.01 μM，响应时间为 3.95 s，线性范围更宽，为 0.01–1000 μM。血清中添加的赖氨酸的分析回收率为 97%。生物传感器的测定内和批间变异系数分别为 0.068 和 0.074%。生物传感器测量健康成人和人类免疫缺陷病毒 (HIV) 患者血清中的 l-赖氨酸水平。该生物传感器与标准分光光度法（R2 = 0.989）表现出良好的相关性。生物传感器在正常使用 180 天后失去了 35% 的原始活性，同时在 4°C 下干燥储存。