Solid-state electrochemiluminescence protein biosensor with aptamer substitution strategy  

作　　者：XU Ying DONG Ping ZHANG XiaoYan HE PinGang FANG YuZhi 

机构地区：[1]Department of Chemistry, East China Normal University, Shanghai 200062, China

出　　处：《Science China Chemistry》2011年第7期1109-1115,共7页中国科学（化学英文版）

摘　　要：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,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)32+).It was built up by modification of Au nanoparticles(AuNPs) and Ru(bpy)3 2+ 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)3 2+-AuNPs/Au electrode 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 fmol/L thrombin was detected out.

关 键 词：electrochemiluminescence biosensor APTAMER tris（2 2＇-bipyridyl）ruthenium（II） 

分 类 号：O657.1[理学—分析化学] TP212.3[理学—化学]