With the outbreak and pandemic of COVID-19, point-of-care testing (POCT) systems have been attracted much attention due to their significant advantages of small batches of samples, user-friendliness, easy-to-use and simple detection. Among them, flexible biosensors show practical significance as their outstanding properties in terms of flexibility, portability, and high efficiency, which provide great convenience for users. To construct highly functional flexible biosensors, abundant kinds of polymers substrates have been modified with sufficient properties to address certain needs. Paper-based biosensors gain considerable attention as well, owing to their foldability, lightweight and adaptability. The other important flexible biosensor employs textiles as substrate materials, which has a promising prospect in the area of intelligent wearable devices. In this feature article, we performed a comprehensive review about the applications of flexible biosensors based on the classification of substrate materials (polymers, paper and textiles), and illustrated the strategies to design effective and artificial sensing platforms, including colorimetry, fluorescence, and electrochemistry. It is demonstrated that flexible biosensors play a prominent role in medical diagnosis, prognosis, and healthcare.

Conductive nanomaterials have recently gained a lot of interest due to their excellent physical, chemical, and electrical properties, as well as their numerous nanoscale morphologies, which enable them to be fabricated into a wide range of modern chemical and biological sensors. This study focuses mainly on current applications based on conductive nanostructured materials. They are the key elements in preparing wearable electrochemical Biosensors, including electrochemical immunosensors and DNA biosensors. Conductive nanomaterials such as carbon (Carbon Nanotubes, Graphene), metals and conductive polymers, which provide a large effective surface area, fast electron transfer rate and high electrical conductivity, are summarized in detail. Conductive polymer nanocomposites in combination with carbon and metal nanoparticles have also been addressed to increase sensor performance. In conclusion, a section on current challenges and opportunities in this growing field is forecasted at the end.

Natural cellulose fibers extracted from Eulaliopsis Binata (EB) were systematically investigated in this paper. Fourier-transform infrared (FTIR), Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) were used to investigate the chemical composition, morphological structure and crystalline structure of the resulting fibers. Furthermore, some basic physical properties of the EB fiber, i.e., mechanical properties, water absorption, antimicrobial performance were also evaluated and discussed. It was found that the non-cellulose substances were sufficiently removed or reduced after the degumming process, but the cellulose I structure was not changed based on the XRD and FTIR results. Meanwhile, the EB fibers exhibited high breaking strength (3.5∼6.9 cN/dtex) and remarkable moisture region (6.3∼7.7%). It also exhibited moderate antimicrobial effects against Escherichia coli. All these results indicated that the BP fibers had properties resembling those of traditional natural cellulose fibers (e.g. cotton and flax); therefore, they could be viewed as a promising alternative source for natural cellulose bundle fibers.