Detection of Redox Status and pH of Fruits and Vegetables Using a Multiplexed SERS-Active Microneedle

To detect the real values of their redox status and pH, a multiplexed SERS-active microneedle, integrated with redox-sensitive and pH-sensitive surface-enhanced Raman scattering (SERS) probes, was inserted into fruits and vegetables with minimal invasion, and then, they were pulled out to obtain SERS signals to indicate their pH and redox status. Ten kinds of fruits and vegetables were detected via the SERS-active microneedles, and they were also used to detect the peels, the fleshes of banana, and different parts and depth of strawberry, respectively. The multiplexed SERS-active microneedle would become a versatile platform to fully evaluate fruits and vegetables in the daily life and food processing and managements.