Fe-N-C nanozyme mediated bioactive paper-3D printing integration technology enables portable detection of lactose in milk

Abstract

Portable 3D printing biosensing devices have great potential as rapid detection and analytical platforms due to their unique characteristics such as high precision and low cost. In this study, a method for rapid determination of lactose in milk was developed based on bioactive paper-3D printing integration technology. The bioactive paper was prepared by combining three enzymes cascade system composed of β -galactosidase, glucose oxidase and Fe-N-C nanozyme (with excellent peroxidase-like activity and superior affinity). In the presence of lactose, the test paper changed from colorless to blue under the condition of TMB, which can be identified by naked eye. With the help of portable chromometer and smart phone, the RGB color index was analyzed and quantified. The entire detection process can be integrated into the 3D printing device that we have designed and completed in 25 min, with the detection limits of qualitative and quantitative were 0.04 g 100 g−1 and 5.61 μg 100 g−1, which could simultaneously satisfy the detection requirements of rapid, sensitive and portable operation. The bioactive paper and 3D printing device are long shelf life (six months) and cost-effective, which means this integration technology has a good application prospect in areas lacking experimental conditions.