S-Space College of Engineering/Engineering Practice School (공과대학/대학원) Dept. of Materials Science and Engineering (재료공학부) Journal Papers (저널논문_재료공학부)
Carbonization of a stable β-sheet-rich silk protein into a pseudographitic pyroprotein
- Issue Date
- Nature Communications, Vol.6, p. 7145
- Silk proteins are of great interest to the scientific community owing to their unique mechanical properties and interesting biological functionality. In addition, the silk proteins are not burned out following heating, rather they are transformed into a carbonaceous solid, pyroprotein; several studies have identified potential carbon precursors for state-of-the-art technologies. However, no mechanism for the carbonization of proteins has yet been reported. Here we examine the structural and chemical changes of silk proteins systematically at temperatures above the onset of thermal degradation. We find that the beta-sheet structure is transformed into an sp2-hybridized carbon hexagonal structure by simple heating to 350 degrees C. The pseudographitic crystalline layers grew to form highly ordered graphitic structures following further heating to 2,800 degrees C. Our results provide a mechanism for the thermal transition of the protein and demonstrate a potential strategy for designing pyroproteins using a clean system with a catalyst-free aqueous wet process for in vivo applications.