Portable devices with the advantages of rapid, on-site, user-friendly, and cost-effective assessment are widely applied in daily life. However, only a limited number of quantitative portable devices are commercially available, among which the personal glucose meter (PGM) is the most successful example and has been the most widely used. However, PGMs can detect only blood glucose as the unique target. Here we describe a novel design that combines a glucoamylase-trapped aptamer-cross-linked hydrogel with a PGM for portable and quantitative detection of non-glucose targets. Upon target introduction, the hydrogel collapses to release glucoamylase, which catalyzes the hydrolysis of amylose to produce a large amount of glucose for quantitative readout by the PGM. With the advantages of low cost, rapidity, portability, and ease of use, the method reported here has the potential to be used by the public for portable and quantitative detection of a wide range of non-glucose targets.
A biocide‐free antifouling method on wetted insulating surfaces, enabled by the oscillation of electric potential generated by an integrated triboelectric wave harvester (I‐TEWH) is reported. Distinct from previous studies that reported antifouling on conducting surfaces by applying an additional power source, this method achieves antifouling on insulating surfaces with zero‐power consumption. The electric potential in the vicinity of a protected surface oscillates in large amplitude as a result of periodically accumulated free electrons on an underlying electrode. The dynamic flow of the free electrons is driven by the I‐TEWH that converts ambient wave energy by solid–liquid interface triboelectrification. As a consequence, the oscillating electric potential disturbs the inherent charge distribution on microbes due to electrostatic induction, preventing their initial adhesion onto the protected surface and thus prohibiting the subsequent formation of macroorganisms. Significant anti‐adhesion efficiencies of as high as 99.3%, 99.1%, and 96.0% are achieved for negative‐gram bacteria (Escherichia coli), positive‐gram bacteria (Staphylococcus aureus), and diatoms (bacillariophyceze), respectively, on a smooth surface. The antifouling efficiency on a roughened surface with micro/nanostructures can be further enhanced by another 75%. This approach can be potentially utilized in coastal constructions, offshore facilities, and vessels that are either moving or stationary in port.
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