Determination of 8-hydroxy-2′-deoxyguanosine in urine with "linear" mode sparked graphite screen-printed electrodes

The development of sensors for diagnostic purposes is of immense importance. Despite the number of proposed sensors showing attractive detection capabilities, the widespread use of these sensors is mainly hindered by selectivity issues and the elaborate tailoring of the sensing surface that eventually increases both the cost of the final sensor and the individual analysis cost. Herein, we report on the development of an advanced sensor for 8-hydroxy-2'-deoxyguanosine (8-OHdG), an important biomarker for DNA oxidative damage. The sensor was developed on a low-cost graphite screen-printed electrode (SPE) by employing for the first time, an extremely fast SPE-to-graphite "linear" mode sparking process that enables the uniform modification of the whole electrode surface in less than 20 s. Graphite-sparked SPEs exhibited a linear relationship with the concentration of 8- OHdG over the range 2-50 nM, while the limit of detection (3 sigma) was 0.35 nM. The sensors showed a notable resistance to interference by 10 00fold excess of dopamine and ascorbic acid, and 100-fold excess of uric acid. A simple treatment of the samples, based on uricase, that eliminates the interference caused by uric acid under real-world conditions (>10 00-fold excess) was optimized and proposed. The method was successfully applied to the determination of 8-OHdG in synthetic urine samples. Recovery was 95%. (C) 2021 Elsevier Ltd. All rights reserved.