Investigating the Effects of Particle Size on the Growth of Silkworm and Fiber Properties with Feeding TiO2 NPs

Abstract

The production method of functional silk by feeding the various nanoparticles is simple, it has attracted the attention of many researchers. However, many researchers have studied the concentrate of nanoparticles (NPs), there are few studies on the particle size. This study is aimed to confirm the effects in silkworm growth, cocoon quality, and mechanical properties of silk with feeding TiO2 NPs of the various particle size. TiO2 10nm, 50nm, 100nm powers individually are fed to silkworm, investigated the mortality and proliferation rate, cocoon mass and cocoon shell mass, mechanical characteristic of silk fiber. The experiments demonstrated that the larger the particle size of TiO2 NPs, the greater the adverse impact on the growth and livability of silkworms. The stress of 523.35±42 MPa and strain of 19.73±1.8% of the TiO2-10nm added silk were increased 35.9% and 19.5% on average, respectively. By the analysis of the Fourier transform infrared (FTIR) spectra, it was confirmed that this resulted in a more random coil/?-helix structure. The nanoparticles are acted as knots, forming the cross-linked network, resulting in lower crystallinity and higher strain, but the larger the particle, the fewer the number of knots, at the same time, it has a great impact on protein synthesis, and then the strength may be decreased. The effect in the silkworm body of TiO2 NPs particle size has to be deeply studied, but this study has important significance to study in the production of the functional silk by feed additives.