Facile preparation of corn starch nanoparticles by alkali-freezing treatment

In this article a facile way of producing starch-based nanoparticles (SNPs) with high yields and predictable size by an alkali-freezing treatment is presented. A new mix solvent, sodium hydroxide-urea aqueous solution, has been developed to disperse corn starch. After refreezing, thawing, stirring at room temperature and dialysis, resultant aqueous suspensions of SNPs are obtained and characterized using a scanning electron microscope (SEM) and dynamic light scattering (DLS) to learn the particle morphology, mean size and size distribution. By adjusting parameters such as the sodium hydroxide : urea ratio and temperature, the size of particles can be controlled from micro-to nanometer. Furthermore, this process that leads to the nanoparticles causes no changes in the structures of the starch granules as characterized by IR or H-1-NMR. Freeze-dried SNPs were found to be amorphous as revealed by wide-angle X-ray diffraction (WAXD).