Paper-based electroanalytical strip for user-friendly blood glutathione detection

Abstract

Paper-based devices are always more gaining a relevant position in the field of sensors. The continuous demand for affordable, simple, sustainable, and portable devices, is making paper as the ideal basis towards the realization of analytical tools for the easy self-testing. In this work, we demonstrate, for the first time, the development of a disposable paper-based printed electroanalytical strip for reliable, rapid, and high-throughput detection of glutathione in blood. The detection is based on the thiol-disulfide exchange reaction, which produces a detectable compound easily oxidizable at a Prussian Blue/carbon black nanocomposite involving a favorable low-interference overpotential. This nanocomposite is mixed within a carbon-based conductive ink and successively screen-printed onto a wax-patterned filter paper. The employment of paper provides a reagent-free device, as a consequence of the reagents pre-loading within the testing area. After the experimental conditions have been optimized, glutathione has been detected up to 10 mM, with a detection limit of 60 μM, and a sensitivity of (0.102 ± 0.005) μA/mM. This sensor showed satisfactory repeatability (relative standard deviation equal to 10%, for detection of glutathione 1 mM), especially by considering the hand-made manufacturing process. The "real-world" applicability of this strip has been evaluated by quantifying blood glutathione at physiological levels and by recovery studies achieving satisfactory values.

Paper-Based Screen-Printed Electrodes: A New Generation of Low-Cost Electroanalytical Platforms

“…In two-dimensional devices, the sample is deposited in the same layer in which the electrochemical cell is printed or flows toward it by capillarity. As commented before, platforms are commonly fabricated by patterning a single piece of paper with a hydrophobic material (e.g., wax or photoresist) that delimits hydrophilic microfluidic channels, areas or reservoirs [ 118 , 119 , 120 , 121 , 122 , 123 , 124 , 125 , 126 , 127 , 128 , 129 , 130 , 131 , 132 , 133 , 134 , 135 , 136 ]. Other materials such as adhesive tape can be used either as an additional stencil for printing the electrodes [ 121 , 137 ] or to delimit the area of the working electrode once the ink has been spread on a specific piece of paper [ 138 ].…”

Advanced Signal-Amplification Strategies for Paper-Based Analytical Devices: A Comprehensive Review

“…The sample was captured by an image box with a smartphone or digital camera and sent to online auto-analyzing software. Under optimized conditions, grayscale values plotted against GSH concentrations exhibited a linear relationship within the range 25–500 µM (LOD 9.80 µM), which is about a six-fold improvement compared with another paper-based electroanalytical test strip [ 70 ], with a highly positive correlation between the detected GSH level and the temozolomide (TMZ) drug-resistance level in glioblastoma multiforme (GBM) cells. Being oxidase-like is another good activity exerted by metal oxides that have been employed for signal improvement in several paper-based devices.…”

Electrochemical Paper-Based Biosensor Devices for Rapid Detection of Biomarkers

“…The detection is based on the thiol-disulfide exchange reaction between this pre-loaded cystamine and the glutathione, which was previously released through a process of blood lysis. This reaction produces cysteamine, a compound easily oxidizable thanks to the electrocatalytic properties of Prussian Blue incorporated in the WE [23]. Moreover, a so-called lab-on-paper device was fabricated for the detection of the breast cancer MCF-7 cell line by using Whatman chromatography paper grade No.…”