Preparation of β-d-glucan nanoparticles and its antifungal activity

This work demonstrates the preparation of β-d-glucan (isolated from the cell wall of Pythium aphanidermatum) nanoparticles through the addition of 2% (w/v) sodium hydroxide to β-d-glucan solution with constant stirring at 90 °C. Addition of sodium tripolyphosphate (TPP) aids the stable formation of nanoparticles. Fourier transform infrared (FTIR) spectroscopy confirmed phosphoric groups of TPP linked with OH group of β-d-glucan in the nanoparticles. The formation of nanoparticles was observed by the peak at 386 nm using UV-vis spectroscopy. The average size of nanoparticle as determined by Zetasizer was about 60 nm, while the zeta potential was negative. Scanning electron microscope image showed spherical, smooth and almost homogenous structure for nanoparticles with size ranging from 20 to 50 nm. Further analysis by TEM, indicated polydispersity with an average size of 20–30 nm. The XRD analysis confirmed the crystalline structure of β-glucan nanoparticle. The prepared nanoparticles exhibited antifungal activity against P. aphanidermatum, a devastating fungus which affects major crop plants.