Biosensors and Bioelectronics, 15 May 2012, Vol.35(1), pp.407-412
► A simple “post-additional” method for antioxidant capacity determination is developed. ► A cheap and stable artificial enzyme, G-quadruplex DNAzyme, is used instead of natural peroxidases. ► The stabilization of the pre-formed ABTS by ATP makes the large-scale preparation of ABTS possible. ► Using this method, the relative antioxidant capacity of antioxidants can be detected and compared easily. ► This method can be used for high-throughput visual screen of antioxidants. The scavenging of 2,2′-azinobis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) radical cation (ABTS ) by antioxidants has been widely used in antioxidant capacity assay. Because of ABTS disproportionation, however, this radical cannot be prepared on a large scale and stored long-term, making it unsuitable for high-throughput detection and screening of antioxidants. We developed a modified “post-additional” antioxidant capacity assay. This method possessed two remarkable features: First, instead of natural peroxidases, an artificial enzyme, G-quadruplex DNAzyme, was used for the preparation of ABTS , thus greatly reducing the cost of the assay, and eliminating the strict demand for the storage of enzymes. Second, an ABTS stabilizer, adenosine triphosphate (ATP), was used. In the presence of ATP, the disproportionation of ABTS was effectively inhibited, and the lifetime of this radical cation was prolonged about 6-fold (12 days versus 2 days), making the large-scale preparation of ABTS possible. Utilizing this method, the antioxidant capacities of individual antioxidants and real samples can be quantified and compared easily. In addition, this method can be developed as a high-throughput screening method for antioxidants. The screening results could even be judged by the naked eye, eliminating the need for expensive instruments.
G-Quadruplex Dnazyme ; Antioxidant Capacity ; ATP ; Abts ; Free Radical ; Engineering ; Biology
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