One solid-state electrochemiluminescence （ECL） protein biosensor based on the competing reaction and substitute reaction between protein-to-DNA aptamer and DNA-to-DNA aptamer was proposed. Additionally, the biosenso...One solid-state electrochemiluminescence （ECL） protein biosensor based on the competing reaction and substitute reaction between protein-to-DNA aptamer and DNA-to-DNA aptamer was proposed. Additionally, the biosensor was based on ECL photo-quenching effect of ferrocene （Fc） to tris（2,2-bipyridyl）ruthenium（II） （Ru（bpy）2＋）. It was built up by modification of Au nanoparticles （AuNPs） and Ru（bpy）32＋ on one Au electrode firstly, and then self-assembly of one special double-stranded DNA （dsDNA） onto the electrode. This dsDNA was prepared by hybridization of one Fc labeled molecular beacon single-stranded DNA（ssDNA） and one anti-thrombin aptamer ssDNA. Without the target protein, this Fc-dsDNA/Ru（bpy）2＋- AuNPs/Au elec- trode trigged strong ECL signal, so we called it ECL ＂signal on＂ state. When thrombin was present in the sensing solution, the protein reacted with its aptamer from the Fc-dsDNA/Ru（bpy）3^2＋-AuNPs/Au electrode. Then the left molecular beacon ssDNA on the electrode recovered to its normal stem-loop structure and consequently its Fc labeler was close enough to the electrode surface to quench the ECL signal from Ru（bpy）3^2＋. It was in ECL ＂signal off＂ state. We measured the decrease in ECL intensity to sense the target protein. This was one endeavour to sense protein by using un-labeling target or probe strategy, which gave higher sensitivity and selectivity due to the better combination efficiency of protein and the un-labeled aptamer. 6.25 fmo/L thrombin was detected out,展开更多
This paper presents a high specific, sensitive electrochemical biosensor for recognition of protein such as thrombin based on aptamers and nano particles. Two different aptamers were chosen to construct a sandwich man...This paper presents a high specific, sensitive electrochemical biosensor for recognition of protein such as thrombin based on aptamers and nano particles. Two different aptamers were chosen to construct a sandwich manner for detecting thrombin. Aptamer I was immobilized on nano magnetic particle for capturing thrombin, and aptamer II labled with nano gold was used for detection. The electrical current generated from gold after the formation of the complex of magnetic particle, thrombin and nano gold, and then an electrochemical cell designed by ourselves was used for separating, gathering, and electrochemical detecting. Through magnetic separation, high specific and sensitive detection of the target protein, thrombin, was achieved. Linear response was observed over the range 5.6×10-12―1.12×10-9 mol/L, with a detection limit of 1.42×10-12 mol/L. The presence of other protein as BSA did not affect the detection, which indicates that high selective recognition of thrombin can be achieved in complex biological samples such as human plasma.展开更多
文摘One solid-state electrochemiluminescence （ECL） protein biosensor based on the competing reaction and substitute reaction between protein-to-DNA aptamer and DNA-to-DNA aptamer was proposed. Additionally, the biosensor was based on ECL photo-quenching effect of ferrocene （Fc） to tris（2,2-bipyridyl）ruthenium（II） （Ru（bpy）2＋）. It was built up by modification of Au nanoparticles （AuNPs） and Ru（bpy）32＋ on one Au electrode firstly, and then self-assembly of one special double-stranded DNA （dsDNA） onto the electrode. This dsDNA was prepared by hybridization of one Fc labeled molecular beacon single-stranded DNA（ssDNA） and one anti-thrombin aptamer ssDNA. Without the target protein, this Fc-dsDNA/Ru（bpy）2＋- AuNPs/Au elec- trode trigged strong ECL signal, so we called it ECL ＂signal on＂ state. When thrombin was present in the sensing solution, the protein reacted with its aptamer from the Fc-dsDNA/Ru（bpy）3^2＋-AuNPs/Au electrode. Then the left molecular beacon ssDNA on the electrode recovered to its normal stem-loop structure and consequently its Fc labeler was close enough to the electrode surface to quench the ECL signal from Ru（bpy）3^2＋. It was in ECL ＂signal off＂ state. We measured the decrease in ECL intensity to sense the target protein. This was one endeavour to sense protein by using un-labeling target or probe strategy, which gave higher sensitivity and selectivity due to the better combination efficiency of protein and the un-labeled aptamer. 6.25 fmo/L thrombin was detected out,
文摘This paper presents a high specific, sensitive electrochemical biosensor for recognition of protein such as thrombin based on aptamers and nano particles. Two different aptamers were chosen to construct a sandwich manner for detecting thrombin. Aptamer I was immobilized on nano magnetic particle for capturing thrombin, and aptamer II labled with nano gold was used for detection. The electrical current generated from gold after the formation of the complex of magnetic particle, thrombin and nano gold, and then an electrochemical cell designed by ourselves was used for separating, gathering, and electrochemical detecting. Through magnetic separation, high specific and sensitive detection of the target protein, thrombin, was achieved. Linear response was observed over the range 5.6×10-12―1.12×10-9 mol/L, with a detection limit of 1.42×10-12 mol/L. The presence of other protein as BSA did not affect the detection, which indicates that high selective recognition of thrombin can be achieved in complex biological samples such as human plasma.
