Impact of SiO2 nanoparticles on the structure and property of type I collagen in three different forms.

Silica-based nanoparticles have found application in the development of biocomposites involving reconstituted collagen in tissue engineering and wound healing, and leather modification, specifically targeting collagen fibers. However, a comprehensive investigation into the interaction between collagen-silica nanoparticles and different forms of collagen using biophysical methods remains unexplored. In this study, we examined the interaction between silica (SiO2) nanoparticles and collagen in its fiber, microfibril, and monomer forms through high-resolution scanning electron microscopy, circular dichroism, Fourier-transform infrared spectroscopy, fluorescence analysis, zeta potential measurements, and turbidity assays. Our results reveal that SiO2 nanoparticles exhibited a non-specific attraction towards collagen fibers without disrupting their structural integrity. Interestingly, SiO2 nanoparticles influenced the process of microfibrillation, resulting in heterogeneous fibril diameters while maintaining the natural D-periodicity. This finding is significant, as fibril size variations can impact the properties of collagen composites. Notably, the triple helical structure of collagen in its monomer form remained unaffected in the presence of SiO2 nanoparticles, indicating that the nanoparticles did not disrupt the electrostatic interactions that stabilize the triple helix. Additionally, the increased stability of SiO2 nanoparticles in the presence of collagen confirmed their interaction. These findings provide a promising avenue for the development of SiO2-based nanoparticles to enhance the stability of collagen fibers and control fiber sizes for biomaterial preparation. Moreover, this study advances the potential application of SiO2-based nanoparticles in leather tanning, an emerging field where nanoparticles can play a crucial role.