Cruz, DianaBarroso, M. FátimaRamalhosa, Maria JoãoCoelho, AndreiaSilva, Hélder daDuarte, Abel J.González-García, Maria BegoñaCarvalho, Ana P.Delerue-Matos, Cristina2017-01-112016http://hdl.handle.net/10400.22/9205Reactive nitrogen and oxygen species are produced in cells and play an important role in the oxidative metabolism; when in abnormal concentrations, they are able to induce oxidative damage on biomolecules, namely in DNA. In this paper it is described, an electrochemical DNA-based sensor against NOradical dot radical developed for total antioxidant capacity (TAC) evaluation. The sensor consisted on dA20 (adenine-rich oligonucleotide) physically adsorbed into carbon paste electrode (CPE). When this dA20-CPE was damaged, by immersion in a freshly generated NOradical dot radical, a protective effect onto dA20 was observed in the presence of antioxidants (ascorbic, gallic, caffeic, p-coumaric acids). Electrochemical studies were performed through square wave voltammetry. The construction of the sensor is simple, fast and the results indicated that the DNA-based sensor is suitable, accurate, and can be used to the assessment of TAC in commercial samples of juices.engDNA-based sensorReactive nitrogen and oxygen speciesElectrochemistryTotal antioxidant capacity (TAC)Commercial juice samplesjournal article10.1016/j.jelechem.2015.12.045