Preparation and characterization of fibroin nanoparticles obtained from Bombyx mori L. Pilamo

Abstract

Silk fibroin (SF) is a biomacromolecule that is composed of proteins with excellent biocompatibility and biodegradability and low immunogenicity. SF nanoparticles (Nps) have received considerable attention for their ability to overcome the disadvantages of non-degradable synthetic nanoparticles. In the present study, the structural and thermal properties of SF derived from the Bombyx mori L. Pilamo 1 hybrid were compared with those of the corresponding Nps. Raw fibroin (RF) was extracted using a sodium Na₂CO₃ solution following an experimental design. The FNps were prepared by denaturing the RF with a ternary solution of CaCl₂:H₂O:CH₃CH₂OH, followed by precipitation using an anti-solvent method with propanol. The silk cocoon, RF and the FNps were characterized using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The thermal properties of RF and the FNps were studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The FTIR results showed that fibroin was produced in the absence of sericin, and the SEM results showed that nanometre-sized particles were produced with a globular structure and apparent porosity. The differences in the enthalpy of the crystallization peaks in the DSC and TGA curves showed that the FNps had a higher thermal stability than the RF fibres. This result furthers the development of alternative materials that can serve as transport media for active compounds of natural extracts.