Self‐Powered, Paper‐Based Electrochemical Devices for Sensitive Point‐of‐Care Testing

Abstract

to enhance the mass transport on the surface of the electrodes and to increase their current response, [5] not requiring external pumps for transporting fluids and offering higher sensitivity and selectivity than other paper-based analytical devices that rely on colorimetric detection. [6] Although the characteristics of PEDs make them especially suited for point-ofcare testing (POCT), these devices-with the exception of blood glucose metersrequire skilled personnel, electric power, and expensive equipment to provide accurate quantitative results. The fabrication of PEDs, which can be used in remote settings, independently of infrastructure constraints, and with the capability to facilitate telemedicine applications to send accurate POCT results to welltrained people who can help providing an optimal treatment would be desirable to promote preventive diagnostics in the field, especially in resource poor areas. Here, we propose to benefit from the latest developments in paper-based electronics and microfluidics to fabricate low-cost, sensitive, and disposable electrochemical analytical devices that can be directly powered by the user, thanks to the integration of a paper-based triboelectric generator (TEG), and be used as a portable alternative for point-of-care diagnostics.Electrochemistry has consistently provided simple and portable techniques to analyze small molecules in complex biological environments with a high degree of specificity and selectivity at a moderate cost. [7] The trend to decrease the cost of electrochemical assays has led to the exploration of low-cost substrates, such as cellulose-based paper and thread, [8][9][10] and novel-printed electrodes and conductive patterns to contribute to low-cost diagnostics. [11,12] Dungchai et al. provided the first quantification of glucose, lactate, and uric acid in serum using chronoamperometry measurements performed by conductive electrodes printed on a paper-based microfluidic channel. [13] Many other PEDs have been developed for the quantification of antibodies, [14] proteins, [1] DNA, [3] ascorbic acid, [15] and metal ions (such as Pb 2+ , Cd 2+ , Zn 2+ …), [4,16] proving that PEDs can provide an inexpensive, versatile, and easy to dispose platform for POCT. In spite of their numerous advantages, PEDs remain relatively underexploited in in-field applications due to the tendency of paper to absorb water from the environment, compromising the performance of the printed electrodes. [7] Other challenges relate to the need of This work describes the fabrication of self-powered, paper-based electrochemical devices (SPEDs) designed for sensitive diagnostics in low-resource settings and at the point of care. SPEDs are inexpensive, lightweight, mechanically flexible, easy to use, and disposable by burning. The top layer of the SPED is fabricated using cellulose paper with patterned hydrophobic domains that delineate hydrophilic, wicking-based microfluidic channels for accurate colorimetric assays, and self-pipetting test zones for electrochemical detection. The ...

Waterproof, Breathable, and Antibacterial Self‐Powered e‐Textiles Based on Omniphobic Triboelectric Nanogenerators

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Multifunctional Skin‐Inspired Flexible Sensor Systems for Wearable Electronics

“…Typically, triboelectric and piezoelectric effects are two reliable approaches to convert mechanical energy to electricity for wearable electronics. Since the first report of flexible triboelectric nanogenerators (TENGs) by Fan et al, several groups have been involved in applying TENGs on skin‐inspired sensors, targeting at the realization of battery‐free monitoring and diagnostic systems . For instance, Pu et al reported a mechnosensational TENG (msTENG)‐based noninvasive micromotion sensor that is capable of translating eye blink into control command based on a multifilm structure, which could be flexibly mounted behind an eyeglass arm ( Figure a) .…”

Flexible Electronics Based on Micro/Nanostructured Paper

“…c) Schematics of the charge generation process in the TENG attached to the bottom of the microfluidic layer. Reproduced with permission . Copyright 2017, WILEY‐VCH.…”

“…Similarly, such device can also be applied to antifouling since the pulse electricity generated by the device can prevent algae (e.g., Dunaliella and Navicula ) from adhering to metallic substrates. By integrating a triboelectric generator with paper microfluidic, Martinez and co‐workers demonstrated self‐powered, electrochemical devices for sensitive POC testing . As illustrated in Figure c, wicking‐based microfluidic channels for accurate colorimetric assays and self‐pipetting test zones for electrochemical determination on the top layer were constructed via wax printing approach.…”