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As one of the biomarkers of coagulation system-related diseases, the detection of thrombin is of practical importance. Thus, this study developed a portable biosensor based on a personal glucometer for rapid detection of thrombin activity. Fibrinogen was used for the detection of thrombin, and the assay principle was inspired by the blood coagulation process, where thrombin hydrolyzes fibrinogen to produce a fibrin hydrogel, and the amount of invertase encapsulated in the fibrin hydrogel fluctuates in accordance with the activity of thrombin in the sample solution. The quantitative assay is conducted by measuring the amount of unencapsulated invertase available to hydrolyze the substrate sucrose, and the signal readout is recorded using a personal glucometer. A linear detection range of 0–0.8 U/mL of thrombin with a limit of detection of 0.04 U/mL was obtained based on the personal glucometer sensing platform. The results of the selectivity and interference experiments showed that the developed personal glucometer sensing platform is highly selective and accurate for thrombin activity. Finally, the reliability of the portable glucometer method for rapid thrombin detection in serum samples was investigated by measuring the recovery rate, which ranged from 92.8% to 107.7%. In summary, the fibrin hydrogel sensing platform proposed in this study offers a portable and versatile means for detecting thrombin using a personal glucometer. This approach not only simplifies the detection process, but also eliminates the need for large instruments and skilled operators, and substantially reduces detection costs. [ABSTRACT FROM AUTHOR]

Signal readout technologies that do not require any instrument are essential for improving the convenience and availability of paper-based sensors. Thanks to the remarkable progress in material science and nanotechnology, paper-based sensors with instrument-free signal readout have been developed for multiple purposes, such as biomedical detection, environmental pollutant tracking, and food analysis. In this review, the developments in instrument-free signal readout technologies for paper-based sensors from 2020 to 2023 are summarized. The instrument-free signal readout technologies, such as distance-based signal readout technology, counting-based signal readout technology, text-based signal readout technology, as well as other transduction technologies, are briefly introduced, respectively. On the other hand, the applications of paper-based sensors with instrument-free signal readout technologies are summarized, including biomedical analysis, environmental analysis, food analysis, and other applications. Finally, the potential and difficulties associated with the advancement of paper-based sensors without instruments are discussed. [ABSTRACT FROM AUTHOR]

Eicosapentaenoic Acid (EPA) is an essential ω-3 polyunsaturated fatty acid for human health. Currently, high-quality EPA production is largely dependent on the extraction of fish oil, but this unsustainable approach cannot meet its rising market demand. Biotechnological approaches for EPA production from microorganisms have received increasing attention due to their suitability for large-scale production and independence of the seasonal or climate restrictions. This review summarizes recent research on different microorganisms capable of producing EPA, such as microalgae, bacteria, and fungi, and introduces the different EPA biosynthesis pathways. Notably, some novel engineering strategies have been applied to endow and improve the abilities of microorganisms to synthesize EPA, including the construction and optimization of the EPA biosynthesis pathway, an increase in the acetyl-CoA pool supply, the increase of NADPH and the inhibition of competing pathways. This review aims to provide an updated summary of EPA production. [ABSTRACT FROM AUTHOR]