构建一种基于杂交链式反应(hybridization chain reaction,HCR)扩增的适配体磁珠荧光传感器。巧妙设计序列HP和发卡序列H1、H2,其中HP是由适配体序列与触发序列结合而成的,并且序列互补形成稳定的二级结构。然后采用戊二醇反应和亲和素...构建一种基于杂交链式反应(hybridization chain reaction,HCR)扩增的适配体磁珠荧光传感器。巧妙设计序列HP和发卡序列H1、H2,其中HP是由适配体序列与触发序列结合而成的,并且序列互补形成稳定的二级结构。然后采用戊二醇反应和亲和素-生物素反应进行适配体功能化磁珠的制备。将阪崎肠杆菌与适配体磁珠一起孵育,HP中的适配体序列识别靶标,引起HP构象变化,露出触发序列,通过HCR触发H1和H2的链状组装,产生长双链DNA。荧光指示剂SYBR Green I以插层和小槽结合的方式与HCR产物的长双链结合。最后加入氧化石墨烯(graphene oxide,GO)后,游离的H1、H2和SYBR Green I将通过π-π堆积紧密吸附在GO表面,荧光信号被猝灭。HCR产物不能被吸附在GO表面,因此与HCR产物结合的SYBR Green I发出依赖于靶浓度的强荧光信号,从而实现阪崎肠杆菌的定量检测。本方法在纯培养条件下的检出限为2CFU/mL,对奶粉的检出限为8CFU/g,对奶粉样品的检测结果与传统微生物培养法具有良好的一致性。该方法具有无需DNA提取,快速、稳定性高、高特异性和高灵敏度等优点,因此为阪崎肠杆菌的现场快速检测提供了一种很有潜力的方法。展开更多
1,3,4-oxadiazole-contanining ligand DPOP(DPOP=2-(11-dipyrido[3,2-a:2',3'-c]phenazine)-5-p-tolyl-1,3,4-oxadiazole) was synthesized by a convenient method and characterized by elemental analysis,IR,1H NMR. Then,...1,3,4-oxadiazole-contanining ligand DPOP(DPOP=2-(11-dipyrido[3,2-a:2',3'-c]phenazine)-5-p-tolyl-1,3,4-oxadiazole) was synthesized by a convenient method and characterized by elemental analysis,IR,1H NMR. Then,corresponding Eu(Ⅲ) complex [Eu(DBM)3(DPOP)] (DBM=1,3-diphenyl-1,3-propanedionate) was prepared and characterized by elemental analysis,IR. The photophysical properties of ligand and its europium complex were investigated. The ligand emitted at 443 nm. There were different PL spectra in solid state and in solution of Eu(DBM)3(DPOP). There are two fluorescent peaks at 614 nm,400 nm in dichloromethane solution of Eu(DBM)3 (DPOP),but in solid state only red emission was observed. This result indicated that efficient energy tranfer could take place from DPOP ligand to europium ion in Eu-complex solid.展开更多
文摘构建一种基于杂交链式反应(hybridization chain reaction,HCR)扩增的适配体磁珠荧光传感器。巧妙设计序列HP和发卡序列H1、H2,其中HP是由适配体序列与触发序列结合而成的,并且序列互补形成稳定的二级结构。然后采用戊二醇反应和亲和素-生物素反应进行适配体功能化磁珠的制备。将阪崎肠杆菌与适配体磁珠一起孵育,HP中的适配体序列识别靶标,引起HP构象变化,露出触发序列,通过HCR触发H1和H2的链状组装,产生长双链DNA。荧光指示剂SYBR Green I以插层和小槽结合的方式与HCR产物的长双链结合。最后加入氧化石墨烯(graphene oxide,GO)后,游离的H1、H2和SYBR Green I将通过π-π堆积紧密吸附在GO表面,荧光信号被猝灭。HCR产物不能被吸附在GO表面,因此与HCR产物结合的SYBR Green I发出依赖于靶浓度的强荧光信号,从而实现阪崎肠杆菌的定量检测。本方法在纯培养条件下的检出限为2CFU/mL,对奶粉的检出限为8CFU/g,对奶粉样品的检测结果与传统微生物培养法具有良好的一致性。该方法具有无需DNA提取,快速、稳定性高、高特异性和高灵敏度等优点,因此为阪崎肠杆菌的现场快速检测提供了一种很有潜力的方法。
文摘1,3,4-oxadiazole-contanining ligand DPOP(DPOP=2-(11-dipyrido[3,2-a:2',3'-c]phenazine)-5-p-tolyl-1,3,4-oxadiazole) was synthesized by a convenient method and characterized by elemental analysis,IR,1H NMR. Then,corresponding Eu(Ⅲ) complex [Eu(DBM)3(DPOP)] (DBM=1,3-diphenyl-1,3-propanedionate) was prepared and characterized by elemental analysis,IR. The photophysical properties of ligand and its europium complex were investigated. The ligand emitted at 443 nm. There were different PL spectra in solid state and in solution of Eu(DBM)3(DPOP). There are two fluorescent peaks at 614 nm,400 nm in dichloromethane solution of Eu(DBM)3 (DPOP),but in solid state only red emission was observed. This result indicated that efficient energy tranfer could take place from DPOP ligand to europium ion in Eu-complex solid.
