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
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,
