We prepared composite films consisting of two biocompatible materials, bacterial
cellulose and silk fibroin. Aqueous silk fibroin solution and bacterial cellulose excreted by
Acetobacter xylinum were used to fabricate the composite films. It was verified by field emission
scanning electron microscopy and X-ray diffraction that the two components were finely blended
and that the silk fibroin was crystallized during the composition of the films. The silk fibroin
penetrated well between the individual fibrils of the bacterial cellulose, while the water molecules
inside the pellicular bacterial cellulose were evaporating. The composite films did not dissolve in
water due to the crystallization of the silk fibroin in the composite films. We also observed the
change in the mechanical properties of the composite films according to the water content. The
composite films became more flexible and tougher when they were dipped in water, whereas they
were very brittle in the dehydrated state.
Physical and mechanical properties of modified bacterial cellulose composite films