基于金纳米团簇/氧化石墨烯的高灵敏复合荧光纳米传感器检测水产品中重金属汞离子

Detection for the heavy metal mercury ions in aquatic products by highly sensitive composite fluorescent nanosensor based on aptamer@gold nanoclusters/graphene oxide

目的基于金纳米团簇(aptamer@gold nanoclusters,Apt@AuNCs)/氧化石墨烯(graphene oxide,GO)的高灵敏复合荧光纳米传感器建立检测水产品中汞离子(Hg^(2+))的方法。方法以寡核苷酸序列为模板通过一步法快速合成具有直接特异性识别Hg^(2+)能力的Apt@AuNCs;Apt@AuNCs作为荧光能量供体,与GO纳米片结合,形成Apt@AuNCs/GO复合荧光纳米体系,此时,Apt@AuNCs荧光被GO猝灭;Hg^(2+)以T-Hg^(2+)-T结构与Apt@AuNCs结合,使得Apt@AuNCs脱离GO表面,体系荧光得到恢复,从而实现Hg^(2+)的快速荧光法检测。结果最佳检测条件为:选择适配体序列为CCCCCCCCCCCCTTCTTTCTTCCCCTTGTTTGTT、GO质量浓度为0.30 mg/mL、激发波长为345 nm、GO与Apt@Au NCs孵育时间为35 min。该方法的Hg^(2+)检出限为0.189 nmol/L,定量限为0.630 nmol/L,线性范围为0.5~10.0 nmol/L。选择小龙虾和鲢鱼作为实际检测样品,通过标准加入法进行测试,其加标回收率为87.18%~109.90%。结论该复合荧光纳米体系无需复杂预处理,实现了对实际样品中Hg^(2+)的现场、简单快速且高灵敏的测定,为水产品中Hg^(2+)的检测提供了一种新思路。

Objective To establish highly sensitive composite fluorescent nanosensor based on aptamer@gold nanoclusters(Apt@AuNCs)/graphene oxide(GO)for the detection of mercury ions(Hg^(2+))in aquatic products.Methods Gold nanoclusters with the ability to recognize Hg^(2+)directly and specifically were synthesized by a one-step method using oligonucleotide sequences as templates(Apt@AuNCs);Apt@AuNCs as a fluorescence energy donor,was combined with GO nanosheets to form Apt@AuNCs/GO composite fluorescence nanosystem.At this time,Apt@AuNCs fluorescence was quenched by GO;Hg^(2+)was combined with Apt@AuNCs in T-Hg^(2+)-T structure,which made Apt@AuNCs off the GO surface and the fluorescence of the system was recovered,so as to realize the rapid fluorescence detection of Hg^(2+).Results The optimal detection conditions were:Selecting the ligand sequence as CCCCCCCCCCCCTTCTTTCTTCCCCTTGTTTGTT,the mass concentration of GO of 0.30 mg/mL,excitation wavelength of 345 nm,and the incubation time of GO and Apt@AuNCs was 35 min.The limit of detection Hg^(2+)was 0.189 nmol/L,the limit of quantitation Hg^(2+)was 0.630 nmol/L,and the linear range was 0.5-10.0 nmol/L.Crayfish and silver carp were selected as the real test samples,and the recoveries of standard addition were87.18%-109.90%.Conclusion The composite fluorescent nanosystem can be used to determine Hg^(2+)in real samples in a simple,rapid and highly sensitive manner without complicated pretreatment.It provides a new idea for the detection of Hg^(2+)in aquatic products.