Investigating silk yield and morphological changes in silk fibres obtained from silkworms fed with Ag and/or $\hbox {TiO}_{2}$ nanoparticles

Abstract

Natural polymers like silk can be augmented in vivo with metallic elements to improve their intrinsic properties and stability. This study demonstrates the uptake of Ag and/or $\hbox {TiO}_{2}$ nanoparticles as diet supplements by silkworms. Nanoparticles dose on morphological changes in silk fibroin fibres and a change in overall silk yield was investigated. Though significant fibre reinforcement with Ag and/or $\hbox {TiO}_{2}$ was not noticed; an increase of 6% in the silk production was observed when silkworms fed with a particular composition of $\hbox {Ag} + \hbox {TiO}_{2}$ nanoparticles (0.37 mM each) in their diet. Here, an average diameter of the degummed silk fibre was ${\sim }10.91 \upmu \hbox {M}$ with a roughness parameter value $R_{\mathrm{q}}$ being 134. This value is comparable to silk fibres obtained from silkworms fed with $\hbox {Ag} + \hbox {TiO}_{2}$ (0.22 $+$ 0.53 mM) nanoparticles and this $R_{\mathrm{q}}$ value was also low when compared to the other tested compositions with nanoparticles. Silks from the control samples (devoid of nanoparticles in their feed) had high diameter fibres and are with low $R_{\mathrm{q}}$ values and silk yield. However, nanoparticle supplementation to the silkworm’s diet resulted in low diameter silk fibres with varying roughnessess and with improved silk yield for the tested doses.