MS1-type bioengineered spider silk nanoparticles do not exhibit toxicity in an in vivo mouse model.

Background: Due to factors such as silk sequence, purification, degradation, morphology and functionalization, each silk variant should be individually tested for potential toxicity. Aim:  In vivo toxicological evaluation of the previously characterized bioengineered H2.1MS1 spider silk particles that can deliver chemotherapeutics to human epidermal growth factor receptor 2-positive breast cancer. Materials & methods: Silk nanoparticles (H2.1MS1 and control MS1) were administered intravenously to mice, and then the organismal response was assessed. Several parameters of acute and subchronic toxicity were analyzed, including animal mortality and behavior, nanosphere biodistribution, and histopathological analysis of internal organs. Also, the complete blood count, as well as the concentration of biochemical parameters and cytokines in the serum, were examined. Results & conclusion: No toxicity of the systemically administrated silk nanosphere was observed, indicating their potential application in biomedicine.