Polymer Nanoparticles: Preparation Methods and Structural Characterization

The synthesis of functional nanoscale particles and their composites is of increasing interest for biomedical and materials science applications. Silk fibroin, a biocompatible and surface-active polymer, offers tunable properties for such purposes. Silk fibroin micro- and nanoparticles were synthesized via hydrolysis at an alkaline modulus of 1:6, temperatures of 180°C, and durations of 120–150 min. Particle morphology, size distribution, and crystallinity were characterized by dynamic light scattering (DLS), atomic force microscopy (AFM), and X-ray diffraction (XRD). The particles obtained were white, odorless, ultra-spherical fine powders, almost insoluble in water, with a bulk density of 650–750 kg/m³. At 120 min, size distribution was 70.6% at 16.54 nm and 29.4% at 240 µm. At 150 min, it shifted to 96.5% at 82.07 nm and 3.5% at 100 µm. AFM revealed morphological changes from needle-like to spherical shapes with prolonged hydrolysis, while XRD indicated increased crystallinity with reaction time, though excessive acid concentration reduced order. Hydrolysis time strongly affects silk fibroin nanoparticle size distribution and morphology. The optimized conditions-180°C for 150 min at 1:6 alkaline modulus-yield predominantly spherical nanoparticles with controlled crystallinity. These findings provide a basis for tailoring fibroin-based materials for targeted applications in nanotechnology and biomedicine.