High-Strength Silk from Silkworms Fed Nitrogen-Doped Carbon Quantum Dots.

The excellent mechanical properties of fluorescent silk play a crucial role in biomedical applications, such as in tendon scaffolds and surgical sutures. However, producing fluorescent silk with high mechanical performance remains challenging. In this study, we proposed a facile strategy to enhance silk properties by feeding silkworms nitrogen-doped carbon quantum dots (N-CQDs). The effects of N-CQDs intake on silkworms, cocoons, and silk were systematically investigated. Results showed that N-CQDs did not affect silkworm survival and significantly improved the silk's breaking strength and elongation at break by up to 40.97% and 20.45%, respectively. The N-CQDs promoted the synthesis of amino acids with small side groups, increasing crystallinity and contributing to the mechanical reinforcement of the silk. The resulting high-strength fluorescent silk exhibited no hemolysis or cytotoxicity, demonstrating great potential as a biomaterial for various biomedical applications.