Paper-Based Sensing Device for Electrochemical Detection of Oxidative Stress Biomarker 8-Hydroxy-2′-deoxyguanosine (8-OHdG) in Point-of-Care

Abstract

This work presents a cost-effective, label-free in point-of-care (POC) biosensor for the sensitive detection of 8-hydroxy-2′-deoxyguanosine (8-OHdG), the most abundant oxidative product of DNA, that may allow a premature assessment of cancer disease, thereby improving diagnosis, prognostics and survival rates. The device targets the direct detection of 8-OHdG by using for the first time a carbon-ink 3-electrode on a paper substrate coupled to Differential Pulse Voltammetry readings. This design was optimized by adding nanostructured carbon materials to the ink and the conducting polymer PEDOT, enhancing the electrocatalytic properties of the sensor towards 8-OHdG detection. Meanwhile, the ability of this oxidative stress biomarker to undertake an oxidation reaction enabled the development of the sensing electrochemical device without the need of chemical probes and long incubation periods. This paper-modified sensor presented high electrochemical performance on the oxidation of 8-OHdG with a wide linear range (50–1000 ng/ml) and a low detection limit (14.4 ng/ml). Thus, our results showed the development of a direct and facile sensor with good reproducibility, stability, sensitivity and more importantly, selectivity. The proposed carbon-based electrochemical sensor is a potential candidate to be miniaturized to small portable size, which make it applicable for in-situ 8-OHdG sensing in real biological samples.

Sepsis and Oxidative Stress in the Newborn: From Pathogenesis to Novel Therapeutic Targets

“…As some markers of oxidative stress, along with indicators of antioxidant defense, are available as point-of-care test (POCT), the confirmation of a relationship between oxidative stress markers and sepsis severity would be of major relevance in critical care settings. Particularly, available or under development POCTs for oxidative stress and antioxidant status include free oxygen radicals test [ 56 , 57 ], free oxygen radicals defense test [ 56 , 57 ], 8-hydroxy-2′-deoxyguanosine [ 58 ], 3-nitrotyrosine [ 59 ], CuZn SOD [ 60 ], BAP, measured as capacity of reduction of ferric to ferrous ions [ 57 ], and iridium-reducing assay, particularly sensitive to GSH [ 61 ]. Despite at present these POCTs have been studied in the adult population, they would offer several advantages for critically ill newborns, as timely manner stratification of sepsis severity and identification of a patient who would particularly benefit from antioxidant strategies, the need for small blood samples, and the possibility to monitor the response to antioxidant treatment.…”

The potential of paper-based diagnostics to meet the ASSURED criteria

“…Materials development for printed and wearable electrochemical sensors have seen extensive growth, 7 with examples for diagnostic applications ranging from water quality monitoring 67 to cancer detection. 68 Paper-based electrochemical sensors have been successfully implemented for detection of glucose, diabetes markers total and glycated haemoglobin (HbA1c) and heavy metals in serum, 69 showing high sensitivity within clinically relevant ranges. Stability, accuracy and shelf life of paper-based electrochemical sensors need to be explored but show promise as effective on-board sensors for ASSURED paper-based diagnostics.…”

Controlling parameters and characteristics of electrochemical biosensors for enhanced detection of 8-hydroxy-2′-deoxyguanosine

“…Most of them just describe how modifying the WE with nanostructures for improving sensitivity and limit of detection. Carbon nanotubes 22–25 , and graphene 24,26,27 have been commonly reported as good WE for the detection of 8-OHdG. Despite their higher conductivity and specificity, biosensors built with these materials showed sensitivity in the picomolar range.…”