Hui Sun

Flexible electrochemical sensors based on noninvasive materials can continuously monitor blood glucose levels in sweat, making them ideal for personal diabetes management intelligent devices. It is necessary to construct sweat glucose electrochemical sensors that have the ability to both adjust to human skin and reliably monitor. We first synthesized nickel/cobalt metal-organic framework material (Ni/Co-MOF) nanosheets via a solvent-thermal approach. Then, an oil-based polyurethane (OPU)/polypropylene spun-bonded nonwoven fabric (PPSF) was obtained by coating the surface of PPSF. Silver/silver chloride (Ag/AgCl) paste and conductive carbon (C) paste were printed layer-by-layer on the surface of the OPU/PPSF by screen printing, followed by the immobilization of Ni-Co/MOF nanosheets on the working area using a Nafion solution to form a Ni/Co-MOF@OPU/PPSF flexible glucose sensor for continuous monitoring of glucose in sweat. This Ni/Co-MOF@OPU/PPSF flexible glucose sensor retained the high electrocatalytic activity of Ni/Co-MOF for glucose oxidation and exhibited high sensitivity (159.9 μA/mM·cm²), low limit of detection (LOD) (2 μM), and a wide linearly glucose-monitoring range (10 μM-1 mM). Compared to other nonenzymatic sensors, our Ni/Co-MOF@OPU/PPSF flexible glucose sensor has better immunity than other substances present in sweat. Meanwhile, the Ni/Co-MOF@PPSF flexible glucose sensor not only monitors the glucose in sweat at different body temperatures but also maintains good mechanical flexibility and stable electrochemical properties under bending conditions. It is suggested that our flexible glucose sensor can be used for continuous monitoring of glucose in human sweat. Overall, our glucose sensor can be used for the continuous monitoring of glucose in human sweat.

Incorporating biomass (e.g., bacterial cellulose, BC) pressure-sensing structures into plantar monitoring technologies could effectively defend users against insecure wear and inaccurate detection, while their capability in sensing pressure continuously when subjected to large pressure is hindered by their natural two-dimensional structure. Here, we present a microbial engineering strategy for fabricating hierarchical fully biomass pressure sensors (HFBPSs) with sufficient sensing capabilities and good structural stability for plantar pressure detection. Particularly, the incorporation of the biobased material loofah enables HFBPS to adopt a hierarchical structure from micro- and nanostructured sensing networks, allowing for dynamic changes in the series-parallel configuration of the circuit under large pressure. This innovative structure design breaks the bottleneck of low operating range encountered by traditional rigid two-dimensional BC pressure sensors, ensuring the HFBPS with ultrahigh sensitivity (2.82 kPa^-1) and wide detection range (0-600 kPa). In addition to stably monitoring gait motions, the HFBPS integrated into smart insoles can recognize nonstandard Tai Chi movements. Our HFBPS with exceptional pressure-sensing performance provides significant impact on the future development of smart insoles for plantar monitoring.

Previous studies have confirmed that MnO_x removes heavy metal ions and organic pollutants from water with dual effects of adsorption and oxidation coupling, significantly improving the ability to remove impurities. Nanometal oxides have a highly reactive surface but tend to agglomerate during preparation and are challenging to recycle after use. A common method is to combine nano-MnO₂ with Fe₃O₄ to prepare magnetic materials for easy recycling. Our previous research has confirmed that catechol (CA) and (3-aminopropyl) triethoxysilane (KH550) can be co-deposited on the surface of polypropylene nonwovens to form a stable CK coating under alkaline conditions. In addition, the coating has many active groups, including hydroxyl groups, amino groups, etc. This study further investigates the secondary reactivity of CK coatings. The coordination of catechol groups and metal ions was used to anchor manganese ions to the coating. Meanwhile, the hydroxyl and amino groups were used to reduce manganese ions to Mn⁴⁺ in situ to prepare PP-(CK-MnO₂). We found that the sample had an excellent decolorization effect on cationic dyes but was limited to anionic dyes. The decolorization mechanism of cationic dyes was further discussed. The results showed that the decolorization of cationic dyes had a dual effect of adsorption and oxidative degradation. Under acidic conditions, its oxidation properties were enhanced. It can be used as a highly effective decolorizing agent for cationic dyes, and the decolorization behavior is consistent with the first-order kinetics. As the pH increases, its oxidation properties gradually decrease. Although the electrostatic adsorption effect was enhanced, the overall decolorization performance was significantly reduced. Recycling experiments have proved that it can maintain >90% removal rate after five cycles. This study also demonstrated that the CK coating has dopamine-like properties, which can coordinate with metal ions to prepare metal-organic hybrid materials.