Synthesis and cytotoxicity of starch nanocrystals produced by unconventional acid hydrolysis subjected to a factorial design

An experimental design was applied to obtain starch nanocrystals (SNCs) by an unconventional acid mixture of HCl/H3PO4, as well as to evaluate its cytotoxicity (study never before reported in the literature). The results indicated SNCs at the nanometer scale with better stability for SNCs/Exp2 (96.5 ± 1.4 nm and –32.15 ± 0.95 mV), which was chosen for the other characterizations. An increase in crystallinity was observed resulting from the high degree of hydrolysis (95.51%), loss of molar mass (19.45%) and reduced polydispersity (26.90%). Another corroborating factor was the narrowing of signals in FTIR analysis (bands at 995 and 1047 cm−1) and XRD (%C = 39.17%). Their thermal properties (TGA/DSC) showed mass losses of 9.29% (dehydration), 82.30% (thermal decomposition) and 8.41% (waste) and three thermal events (glass transition, endothermic transition and thermal decomposition), respectively. In this way, through the pre-established conditions and the results obtained for the SNCs/Exp2, new studies will be conducted to incorporate it in formulations for food applications (coatings or packaging) and hydrogels/films for wound healing, as they showed promising colloidal properties and low cytotoxicity against human cells.