Preparation and characterization of prothioconazole-loaded fluorescent mesoporous silica nanoparticles

Recently, as a novel broad-spectrum fungicide, prothioconazole has attracted much attention. However, the use and registration of prothioconazole in China were restricted due to its metabolites which has great health risks to operators. Therefore, an effectively method to decrease its toxicity is the preparation of the slow release formulation. In this work, the slow release system of prothioconazole-loaded fluorescent mesoporous nanoparticles was prepared. The surface morphology and structure were characterized and analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) surface analysis, thermogravimetric analysis (TGA) and high performance liquid chromatography (HPLC). The release behavior of nanoparticles was evaluated by the dialysis bag method. The growth rate method was employed to study the virulence against Fusahum graminearum Sehw. The optical properties was investigated by fluorescence spectrometer and the transmission of the nanoparticles in fungi and wheat plant were characterized by confocal laser scanning microscopy (CLSM). The results showed that the prepared pesticide-loaded nanoparticles (Pro@FL-MSN) exhibited regular appearance with the maximum drug loading of 27.14% and the average particle size was 139 nm. The results of the release study indicated that the release rate was consistent with the Ritger-Peppas equation. The fungicidal activity of Pro@FL-MSN was similar to that of prothioconazole technical. Moreover, CLSM results showed that the fluorescent silica nanoparticles could be absorbed and transfer into the mycelium and the roots of wheat plant.