基于蛋白模板金纳米簇及羟基氧化钴纳米片的激活型荧光纳米探针用于免标记和灵敏检测生物硫醇

该文基于牛血清白蛋白模板金纳米簇(BSA@AuNCs)与羟基氧化钴(CoOOH)纳米片构建了一种激活型荧光纳米探针用于生物硫醇的检测。带负电的BSA@AuNCs能通过静电吸附作用组装到带正电的CoOOH纳米片表面,与此同时,BSA@AuNCs的荧光由于内滤效应(IFE)有效地被CoOOH纳米片猝灭,形成BSA@AuNCs-CoOOH纳米探针。当向纳米探针溶液加入生物硫醇(0.05~150μmol/L)时,生物硫醇与纳米探针中的CoOOH纳米片发生氧化还原反应,CoOOH纳米片被降解生成Co^(2+),同时释放出BSA@AuNCs,BSA@AuNCs荧光信号恢复。结果表明,该纳米探针可以检测低浓度的生物硫醇,对生物硫醇(半胱氨酸、谷胱甘肽和高半胱氨酸)的检出限为30 nmol/L。相对于其他的氨基酸、金属离子及糖类化合物,该纳米探针对生物硫醇具有较高的选择性并成功应用于人血清样品中生物硫醇的检测。

基于羟基氧化钴纳米片的比色和荧光双模法检测砷(Ⅴ)

羟基氧化钴(CoOOH)纳米片的类氧化酶活性因为体系中的As(Ⅴ)被抑制,从而减弱CoOOH纳米片对对苯二胺(PPD)的氧化,溶液吸光度发生变化。基于以上原理,结合对苯二胺氧化物(oxPPD)对染料吖啶橙(AO)的荧光内滤效应(IFE),建立了一种比色和荧光双模法用于As(Ⅴ)的定量检测。考察了不同浓度As(Ⅴ)的吸光度和荧光强度变化规律,并对CoOOH纳米片浓度、 PPD浓度、缓冲液pH、反应温度等条件进行了优化。结果表明:在优化条件下,As(Ⅴ)浓度与相应信号强度具有良好的线性关系,比色法和荧光法的检出限分别为5和4 nmol/L。该方法已用于市中心湖水中As(Ⅴ)的测定。

In situ evolution of surface Co_(2)CrO_(4) to CoOOH/CrOOH by electrochemical method:Toward boosting electrocatalytic water oxidation

Developing non‐noble‐metal electrocatalyst with efficient and durable activity is a urgent task for addressing the sluggish reaction kinetics of electrochemical water oxidation.Structural evolution of the electrocatalyst is an important strategy for achieving enhanced performance.Herein,in situ evolution of surface Co_(2)CrO_(4) to CoOOH/CrOOH(CoOOH/CrOOH‐Co_(2)CrO_(4))by an electrochemical method under alkaline conditions was designed for enhancing the electrocatalytic performance of water oxidation.The experiments demonstrated that the synergy between CoOOH/CrOOH and Co_(2)CrO_(4) resulted in a marked increase in the number of active sites and improved the rate of charge transfer,which enhanced the activity for water oxidation.At a geometrical current density of 20 mA cm^(−2),the overpotential of the oxygen evolution reaction was 244 mV and the turnover frequency was 0.536 s^(−1) in 1.0 M NaOH.