Abstract

Abstract Spider silk is renowned for its exceptional mechanical properties, surpassing those of other natural and many synthetic fibers. Yet, replicating its remarkable properties through synthetic production remains a challenge. The variability in the mechanical properties of synthetic spider silks lacking protective coatings, exacerbated by factors such as spinning conditions and humidity levels, poses an additional challenge, impacting their application potential. Bioconjugation offers a versatile synthetic method to modify protein structures, enhancing their pharmacokinetics, solubility, stability, and immune response. In particular, polyethylene glycol (PEG)‐ylation has emerged as a successful strategy with numerous marketed PEG–protein conjugates. This study introduces synthetic spider silk—multiarm PEG bioconjugates, facilitating spidroin crosslinking, and chemical functionalization while retaining a biomimetic spinning approach. Two different examples demonstrate the potential of this approach to improve the fiber's tensile strength and extensibility, respectively, both leading to an increased toughness modulus. Furthermore, the approach could allow the tuning of fiber mechanical properties without developing a new mini‐spidroin construct and fiber coating with lipids attached to multiarm PEG, potentially mitigating the impact of environmental conditions on synthetic spider silk fibers.