Fe-MoS$_2$ nanoenzyme with photothermal enhanced enzyme activity for glucose colorimetric detection

With the development of nanotechnology, it has been discovered that some nanomaterials have the activity of mimicking enzymes. This type of inorganic nanomaterial with characteristics similar to natural enzymes is called nanoenzyme. Compared with natural enzymes, nanoenzymes have advantages such as low deactivation, good stability, low production and storage costs, surface modification, and large-scale preparation. They have a wide range of applications in fields such as human health, environmental safety, and biosensing. MoS$_2$ can replace natural peroxidase to catalyze the decomposition of H$_2$O$_2$ and is considered to have peroxidase like activity, making it a typical nanoenzyme material. In addition, the Fenton reaction between Fe$_2^+$ and H$_2$O$_2$ can also cause H$_2$O$_2$ to decompose. Both MoS$_2$ and Fe$_2^+$ can cause the decomposition of H$_2$O$_2$, resulting in the production of hydroxyl radicals (OH). Hydroxyl radicals can catalyze the oxidation of chromogenic substrates 3,3',5,5'-tetramethylbenzidine (TMB), generating blue single electron oxidation products (oxTMB) and characteristic absorption peaks at 652 nm. Based on this characteristic, we doped Fe$_2^+$ into MoS$_2$ to obtain Fe-MoS$_2$ composite materials. Firstly, natural glucose oxidase is used to decompose glucose into glucose lactone and hydrogen peroxide. Then, Fe-MoS$_2$ composite material is added, and TMB is added dropwise to observe the blue turning of the mixed solution. Based on the above principle, colorimetric detection of glucose can be achieved. In addition, under infrared irradiation, the activity of peroxidase like enzymes in Fe-MoS$_2$ is enhanced.