A Nanozyme-Based Sensor For Colorimetric Detection Of Tacrolimus By Using UIO-۶۶-NH۲ Metal Organic Framework

A aunctionalized Zr based metal-organic framework (MOF) nanoparticles were synthesized using a one-step solvothermal method. The as-prepared UiO-۶۶-NH۲ nanoparticles acting as nanozymes, have been developed for highly sensitive and selective detection of tacrolimus with the substrate ۳, ۳′, ۵, ۵′-tetramethylbenzidine (TMB) within a few seconds in the presence of hydrogen peroxide (H۲O۲)[۱]. The synthesized MOF was characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FT-IR). The XRD pattern of UiO-۶۶-NH۲ was consistent with the reported results of UiO-۶۶ which confirms crystallinity structure and suitable formation of the functionalized particles. The results of TEM and SEM showed that the particles are in spherical shape with the average size of ۱۰۰-۱۵۰ nm. It was also revealed that UiO-۶۶-NH۲ crystals were inter-grown. FTIR spectra of the solution after sensing illustrated two new peaks which corresponds to proper interactions between the medicine and the nanosensors. These interactions were also affects the size of the tacrolimus particles to increase after sensing. Changing the color of the solution directly from yellow to blue confirms that the nanosensors are able to oxidize TMB to blue color oxidized TMB (oxTMB). Optimum concentration of both TMB and H۲O۲ were experimentally found to be ۳۰mM. The maximum peak wavelength of oxTMB was observed at ۶۵۰ nm[۲]. The addition of tacrolimus and then increasing its concentration led to the production of different products in blue color. A comparison has been done on the sensing of UiO-۶۶ and UiO-۶۶-NH۲ which proved that the functional MOF can speed up the sensing. In experimental measurements, the limit of detection was obtained ۰.۵ mg/L. It can be concluded that the simple and sensitive UiO-۶۶-NH۲/TMB/H۲O۲ colorimetric system can have great promising applications in clinical medicine.