Researchers from Tufts University, Imperial College London and the University of Michigan have developed a new way to transform silk into a high-performance solid material. The process preserves the natural strength of silk fibres while avoiding synthetic additives and energy-intensive chemical treatments. The resulting material approaches the tensile toughness of Kevlar and outperforms natural materials such as wood and bone.

Published in Nature Sustainability, the research introduces a simpler manufacturing method that keeps the original silk fibre structure intact. Conventional silk processing often dissolves the fibres into proteins before reshaping them into new forms. This step weakens the material and requires large amounts of water, chemicals and energy. The new method avoids this stage entirely.

Heat and Pressure Preserve Silk’s Natural Strength

The researchers used commercially available silkworm cocoon fibres from the textile industry. After removing sericin, the natural adhesive coating around the fibres, they aligned the silk and applied controlled heat and pressure. This caused mobile regions within the silk proteins to bond neighbouring fibres together.

By adjusting temperature and pressure, the team could control the density and strength of the final material. Lower settings produced a looser structure, while higher settings created stronger and denser solids. Excessive heat, however, made the material brittle.

The resulting structure resembles wood at a microscopic level. Aligned fibre bundles distribute stress efficiently throughout the material, creating impressive toughness and durability. Researchers reported that fused silk can compete with carbon fibre composites and other advanced engineering plastics. It also showed strong resistance to ballistic impact.

Potential for Lightweight Design and Advanced Manufacturing

The material could offer new opportunities for product designers and manufacturers seeking renewable alternatives to petroleum-based composites. Its combination of strength, lightweight performance and biobased origins may support applications in mobility, consumer products, protective equipment and lightweight structural components.

Researchers also discovered that fused silk has unique optical properties. The material is transparent to visible light and can polarise terahertz radiation. This could make it relevant for medical imaging, sensing technologies and future 6G communication systems.

Biocompatible and Tunable for Medical Use

The research team also investigated how fused silk behaves inside the body. Animal studies showed that the material is biocompatible and produces only mild immune responses. The degradation rate can also be adjusted through processing conditions. Less dense structures allow cells to gradually integrate into the material, while denser versions remain stable for longer periods.

According to the researchers, this tunability could support medical applications such as regenerative implants and orthopaedic fixation devices for bone fractures. The study demonstrates how natural fibres can be engineered into advanced materials that combine performance with sustainability.

Source: Tufts University / EurekAlert!
Photo: Qichen Zhou