title: Label-free sensitive electrogenerated chemiluminescence aptasensing based on chitosan/Ru(bpy)₃²⁺/silica nanoparticles modified electrode.
abstract: In this work, a label-free and sensitive electrogenerated chemiluminescence (ECL) aptasensing scheme for K(+) was developed based on G-rich DNA aptamer and chitosan/Ru(bpy)3(2+)/silica (CRuS) nanoparticles (NPs)-modified glass carbon electrode. This ECL aptasensing approach has benefited from the observation that the G-rich DNA aptamer at the unfolded state showed more ECL enhancing signal at CRuS NPs-modified electrode than the binding state with K(+), which folds into G-quadruplex structure. As such, the decreasing ECL signals could be used to detect K(+). Compared to other aptasensing K(+) approaches previously reported, the proposed ECL sensing scheme is a label-free aptasensing strategy, which eliminates the labeling, separation, and immobilization steps, and behaves in a simple, low-cost way. More importantly, because the proposed ECL sensing mechanism utilizes the nanosized ECL active CRuS NPs to sense the nanoscale conformation change from the aptamer binding to target, it is specific. In addition, due to the great conformation changes of the aptamer's G-bases on CRuS NPs and the excellent ECL enhancing effect of guanine bases to the Ru(bpy)3(2+) ECL reaction, a 0.3 nM detection limit for K(+) was achieved with the proposed ECL method. On the basis of these advantages, the proposed ECL aptasensing method was also successfully used to detect K(+) in colorectal cancer cells.
authors.affiliation: Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University , Xi'an 710062, P.R. China.
authors.forename: Jie
authors.initials: J
authors.lastname: Dang
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Guo
authors.forename: Xingwang
authors.initials: X
authors.lastname: Zheng
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques; D045744:Cell Line, Tumor; D048271:Chitosan / Q000737:chemistry*; D055664:Electrochemical Techniques; D004566:Electrodes; D005465:Fluorocarbon Polymers / Q000737:chemistry; D006801:Humans; D007477:Ions / Q000737:chemistry; D008163:Luminescent Measurements; D053758:Nanoparticles / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D011188:Potassium / Q000032:analysis*; D012822:Silicon Dioxide / Q000737:chemistry
chemical_list: D052157:Aptamers, Nucleotide; D005465:Fluorocarbon Polymers; D007477:Ions; D009942:Organometallic Compounds; C415768:tris(2,2'-bipyridyl)ruthenium(II); C040402:perfluorosulfonic acid; D012822:Silicon Dioxide; D048271:Chitosan; D011188:Potassium