Description
The attachment of cells to biomedical materials can be improved
by using adhesion molecules, present in the extracellular matrix
substances, such as fibronectin, vitronectin, or laminin. In many
cases, Arg-Gly-Asp (RGD) was found to be the major functional
amino acid sequence responsible for cellular adhesion. In the
present study, a method for producing chimerics proteins, RGDCBM,
with functions similar to fibronectin, which contains a
cellulose-binding module (CBM), was developed. The CBM used
was from the cellulosoma of the bacteria Clostridium thermocellum.
The genes encoding these CBM-containing chimeric proteins
were cloned, and the protein expressed and purified. Bacterial
cellulose (BC) secreted by Gluconacetobacter xylinus was produced.
Polystyrene surfaces and bacterial cellulose sheets where
‘‘coated’’ with these RGD-containing proteins, and then used in
adhesion/biocompatibility tests, using a mouse embryo fibroblasts
culture. The results showed that the proteins containing the RGD or
GRGDY sequence were able to improve the adhesion of the fibroblast
on the polystyrene plate, furthermore proteins containing
the RGD sequence were more effective than the proteins containing
the GRGDY sequence. Preliminary adhesion studies of
fibroblast cultures on cellulose sheets, functionalized with the recombinant
proteins, showed positive effects on the adhesion and
proliferation of the cells. The results demonstrated that the proteins
containing the RGD sequence were able to increase significantly
the adhesion of fibroblast to BC surfaces when compared with the
controls (cellulose treated with the CBM or buffer). The results
also demonstrated that the protein containing one RGD sequence
have a stronger effect than the protein containing two RGDs.