Multifunctional Sensors Made with Conductive Microframework and Biomass Hydrogel for Detecting Packaging Pressure and Food Freshness

Food packaging detection devices have attracted attention to optimize storage situations and reduce food spoilage. However, low-cost and highly sensitive multifunctional sensors for detecting both food freshness and packaging pressure are still lacking. In this study, a multifunctional sensor was developed consisting of a MXene coated alcohol-soluble polyurethane fiber network (MXene/APU) and composite biohydrogel films made of konjac glucomannan, chitosan, and blueberry anthocyanin (KCB). Based on the pressure sensitivity of MXene/APU and the color changes of KCB in response to pH values, the sensor can detect internal package bulging, external squeezing, and food deterioration. The pressure sensor shows a sensitivity of 1.16 kPa^-1, a response time of 200 ms, a wide strain range of 1092%, and stability over multiple loops. The pressure sensor could detect human motion and identify surface morphologies. The excellent sensor performance was attributed to the porous structure and large specific surface area of microfiber networks, conductivity of MXene nanosheets, and protective effect of KCB films coated on the conductive membrane. Besides, the microfluidic blow-spinning method used to prepare microfiber networks showed the advantages of low energy consumption and high production efficiency. Based on the color changes of blueberry anthocyanin loaded in KCB films in response to pH, the sensor realized sensitive spoilage detection of food containing protein. This study provides a new multifunctional food packaging sensing device and a greater understanding of the optimization and application of related devices.