To make the nanocomposite, Raffaele Mezzenga of ETH Zurich and his colleagues added graphene oxide sheets to a solution of silkworm proteins. The researchers also added a drop of hydrazine to reduce the graphene oxide to graphene. Stirring the black suspension for six hours at 70 °C produced silk-covered graphene sheets. The 3.5-nm silk fibers closely resemble the structure of natural spider silk rather than reconstituted silkworm silk, leading the team to believe that graphene directs self-assembly of the proteins to form fibers in a new way. The silk-graphene sheets are 100 times as conductive and about 10 times as tough as the pure graphene oxide starting material. The researchers showed that the composite readily supports growth of human cervical cancer cells, outperforming pure graphene as a cell growth medium. /articles/92/i6/Graphene-Directs-Silk-Nanofiber-Growth.html 20140210 Flexible, strong, conductive silk-graphene nanocomposite could be used as a scaffold for tissue engineering and in biosensor applications Concentrates 92 6 /magazine/92/09206.html Graphene Directs Silk Nanofiber Growth silk, graphene, nanocomposite, silkworm, tissue engineering con scitech Journal News and Community materials This AFM image reveals strands of silk nanofibers covering a sheet of graphene.
by Journal News and Community |
February 10, 2014