title: In-situ produced ascorbic acid as coreactant for an ultrasensitive solid-state tris(2,2'-bipyridyl) ruthenium(II) electrochemiluminescence aptasensor.
abstract: Herein, an ultrasensitive solid-state tris(2,2'-bipyridyl) ruthenium(II) (Ru(bpy)(3)(2+)) electrochemiluminescence (ECL) aptasensor using in-situ produced ascorbic acid as coreactant was successfully constructed for detection of thrombin. Firstly, the composite of Ru(bpy)(3)(2+) and platinum nanoparticles (Ru-PtNPs) were immobilized onto Nafion coated glass carbon electrode, followed by successive adsorption of streptavidin-alkaine phosphatase conjugate (SA-ALP) and biotinylated anti-thrombin aptamer to successfully construct an ECL aptasensor for thrombin determination. In our design, Pt nanoparticles in Ru(bpy)(3)(2+)-Nafion film successfully inhibited the migration of Ru(bpy)(3)(2+) into the electrochemically hydrophobic region of Nafion and facilitated the electron transfer between Ru(bpy)(3)(2+) and electrode surface. Furthermore, ALP on the electrode surface could catalyze hydrolysis of ascorbic acid 2-phosphate to in-situ produce ascorbic acid, which co-reacted with Ru(bpy)(3)(2+) to obtain quite fast, stable and greatly amplified ECL signal. The experimental results indicated that the aptasensor exhibited good response for thrombin with excellent sensitivity, selectivity and stability. A linear range of 1 × 10(-15)-1 × 10(-8) M with an ultralow detection limit of 0.33 fM (S/N=3) was obtained. Thus, this procedure has great promise for detection of thrombin present at ultra-trace levels during early stage of diseases.
authors.affiliation: Education Ministry Key Laboratory on Luminescence and Real-Time Analysis, College of Chemistry and Chemical Engineering, Southwest University, No. 2 Tiansheng Road, Chongqing 400715, People's Republic of China. yuhong87@swu.edu.cn
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Liao
authors.forename: Ruo
authors.initials: R
authors.lastname: Yuan
authors.forename: Yaqin
authors.initials: Y
authors.lastname: Chai
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhuo
authors.forename: Yali
authors.initials: Y
authors.lastname: Yuan
authors.forename: Lijuan
authors.initials: L
authors.lastname: Bai
authors.forename: Li
authors.initials: L
authors.lastname: Mao
authors.forename: Shirong
authors.initials: S
authors.lastname: Yuan
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D052157:Aptamers, Nucleotide / Q000378:metabolism*; D001205:Ascorbic Acid / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism*; D015374:Biosensing Techniques / Q000379:methods*; D004800:Enzymes, Immobilized / Q000378:metabolism; D008163:Luminescent Measurements / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry; D009942:Organometallic Compounds / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry; D012680:Sensitivity and Specificity; D013917:Thrombin / Q000032:analysis* / Q000378:metabolism
chemical_list: D052157:Aptamers, Nucleotide; D004800:Enzymes, Immobilized; D009942:Organometallic Compounds; C415768:tris(2,2'-bipyridyl)ruthenium(II); C081676:thrombin aptamer; C011669:ascorbate-2-phosphate; D010984:Platinum; D000469:Alkaline Phosphatase; D013917:Thrombin; D001205:Ascorbic Acid