An ultrasensitive label-free colorimetric biosensor for the detection of glucose based on glucose oxidase-like activity of nanolayered manganese-calcium oxide.

During the last years, enzyme-based biosensors have gained much more attention among the researchers and have had great success in the determination of different biological macromolecules. Nanomaterials with intrinsic enzyme-mimic activity are widely used in biomedicine as artificial enzymes. Here, we report glucose oxidase-mimic activity of nanolayered manganese-calcium (Mn-Ca) oxide nanoparticles (NL-MnCaO2). In this work, NL-MnCaO2nanoparticles were synthesized and characterized using different techniques including transmission electron microscopy (TEM), scanning electron microscopy (SEM), fourier-transform infrared spectroscopy (FTIR) and powder X-ray diffraction (XRD). Also, the ability of these compounds for the glucose and hydrogen peroxide (H2O2) determination was investigated. A non-enzymatic strategy for the colorimetric detection of glucose and H2O2 was reported which can be utilized not only for the rapid detection and analysis of glucose by the naked eye but also the quantitative assay of glucose by spectrophotometry. The in situ generated H2O2 and gluconic acid (GA) from the oxidation of glucose through the glucose oxidase-mimicking activity of NL-MnCaO2 was detected using a colorimetric method. Also, the results confirmed the application of these compounds for the detection of glucose in human serum samples with a detection limit (LOD) of 6.12 × 10-6 M. The results showed that NL-MnCaO2 can be used as an alternative for the natural enzymes and act as a simple, sensitive and enzyme-free biosensor for the detection of glucose in real samples. The proposed strategy shows some advantages including sensitivity, short detection time and low detection limit.