title: Colorimetric detection of cholesterol with G-quadruplex-based DNAzymes and ABTS2-.
abstract: A novel colorimetric method for detection of cholesterol was developed with hemin-G-quadruplex DNAzyme by transducing oxidation of cholesterol into the color change of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS(2-)). Oligonucleotide 5'-GTGGGTAGGGCGGGTTGG-3' (Oligo-1) formed G-quadruplex structure in the presence of K(+), it acted as a horseradish peroxidase (HRP) mimicking DNAzyme when binding hemin and catalyzed the oxidation of colorless ABTS(2-) to green ABTS(·-) by H(2)O(2), which was produced by the reaction of cholesterol and oxygen that catalyzed by cholesterol oxidase. Therefore, the oxidation of cholesterol could be transduced into the color change of ABTS(2-) by combining these two reactions. Under the optimum conditions, the absorbance was proportional to the concentration of cholesterol over the range of 1.0-30 μM, with a linear regression equation of A=0.362+0.0256C (C: μM, R=0.998) and a detection limit of 0.10 μM (3σ/slope). Moreover, the practicability of the assay in the detection of cholesterol in human serum was studied as well.
authors.affiliation: School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou, PR China.
authors.forename: Ruimin
authors.initials: R
authors.lastname: Li
authors.forename: Cen
authors.initials: C
authors.lastname: Xiong
authors.forename: Zhiyou
authors.initials: Z
authors.lastname: Xiao
authors.forename: Liansheng
authors.initials: L
authors.lastname: Ling
mesh_terms: D052160:Benzothiazoles / Q000737:chemistry*; D002784:Cholesterol / Q000097:blood*; D002789:Cholesterol Oxidase / Q000737:chemistry; D002942:Circular Dichroism; D003116:Color; D003124:Colorimetry; D021881:DNA, Catalytic / Q000737:chemistry*; D054856:G-Quadruplexes; D006427:Hemin / Q000737:chemistry; D006735:Horseradish Peroxidase; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D057230:Limit of Detection; D016014:Linear Models; D018716:Molecular Mimicry; D009841:Oligonucleotides / Q000737:chemistry; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D011188:Potassium / Q000737:chemistry; D013451:Sulfonic Acids / Q000737:chemistry*
chemical_list: D052160:Benzothiazoles; D021881:DNA, Catalytic; D009841:Oligonucleotides; D013451:Sulfonic Acids; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; D006427:Hemin; D002784:Cholesterol; D006861:Hydrogen Peroxide; D002789:Cholesterol Oxidase; D006735:Horseradish Peroxidase; D011188:Potassium; D010100:Oxygen