Morphing in Soft Composite Materials for Biomedical Applications

Background: Man-made materials and structures usually tend to be rigid, however, in nature- soft materials prevail. Natural materials are characterized in highly efficient structures, achieved by thousands years of evolution. They are constructed as multi-scaled composites made from relatively simple building blocks and consist of inherent structural motifs resulting in superior mechanical properties, making them mechanically intelligent” materials. one of these properties is the ability to change their shape (e.g. morphing). Mimicking these structures in using synthetic composites holds great advantages biomedical technologies.

Methods: This study introduces a new soft composite material system based on silk fibers and alginate hydrogel. Silk fibers are strong and inexpensively, they can be easily aligned and reinforce a hydrogel matrix to create a soft composite laminate. Stacking these composite laminates in asymmetrical structure, results in coupling effect for in-plane/bending/twisting deformations of the morphing structure to obtain newly morphed structures.

Results: We have designed new biomimetic composite material system based on silk and alginate hydrogel with controlled fiber orientation and fiber volume fraction. The composite laminate demonstrated hyperelastic behavior with large deformations as in natural soft composites. We intend to stack several laminates together asymmetrically in order to test the ability of these composites to perform shape transformation.

Conclusions: We have introduced a new biomimetic soft composite material system with large deformations and hyperelastic material behavior. We aim to demonstrate its ability to perform shape transformation by smart construction of the laminate stacking. These mechanically intelligent materials are a novel and cutting edge research area and hold a great potential for diverse applications in the biomedical engineering field such as tissue engineering and soft robotics.