Dynamic Adhesive Fibers for Remote Capturing of Objects

B. mori silk has been extensively utilized to create Regenerated Silk Fibroin solutions (RSF) for a wide range of technological applications, including tissue engineering, drug delivery, biomaterials, and adhesives. In this study, an RSF-dopamine (DA) composite is introduced that yields easily deployable hydrogel fibers possessing adhesive properties that can be released on demand to capture and retrieve loads from a distance. The RSF-DA serves as an artificial dope, combining the functional attributes of silk fibroin (i.e., hydrogel formation) and dopamine (i.e., adhesion) to instantly generate adjustable hydrogel fibers displaying a sticky behavior. The mechanical strength and adhesive characteristics of this material are assessed using tensile and lap-shear tests. Furthermore, the possibility of tuning these properties is demonstrated by adding chitosan (Ch) and borate ions (BB), leading to remarkable mechanical and adhesive performances up to 107 MPa and 280 kPa, respectively, which allows the retrieval of objects from the ejected structure. This process can be finely tuned to achieve a controlled fabrication of instantaneously formed adhesive hydrogel fibers for manifold applications, mimicking living organisms’ ability to eject tunable adhesive functional threads.