Size-dependent uptake and distribution of AgNPs by silkworm

Silk is an attractive natural fiber due to its excellent mechanical property and biocompatibility. Xenobiotic modification of pristine silk is gaining significant attention to meet specific demands. The silk payload of xenobiotics is affected by their uptake efficiency, bio-distribution, metabolism and excretion. Herein, we systematically evaluated the effect of nanoparticle size (20-100 nm) on the bio-distribution and silk production by introducing silver nanoparticles (AgNPs) into the silkworm diet. Interestingly, the silk payload of AgNPs is highly dependent on their overall size, where 50 nm-AgNPs are prone to accumulate in silk glands and reveal the highest content in produced silk, qualifying silk antibacterial activity to against both Gram-positive and Gram-negative bacteria. These findings provide new insights to understand how nanoparticle properties influence the incorporation of nanomaterials into silk and can optimize the material design.