Ricardo Pinto¹, António L Amaral^1,2, Eugénio C Ferreira¹, Manuel Mota¹, Manuel Vilanova^3,4, Katia Ruel⁵ and Miguel Gama¹

¹IBB-Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal

²Departamento de Tecnologia Química, ESTIG, IPB, Apartado 1038, 5301-854 Bragança, Portugal

³ICBAS – Instituto de Ciências Biomédicas de Abel Salazar, Largo do Professor Abel Salazar 2, 4099-003 Porto, Portugal

⁴IBMC – Instituto de Biologia Molecular e Celular, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal

⁵Centre de Recherches sur les Macromolécules Végétales (CERMAV)-UPR CNRS 5301, BP 53, 38041 Grenoble cedex 9, France

BMC Biotechnology 2008, 8: 1 [Open Access].

Abstract

Background

Cellulose Binding Domains (CBD) were conjugated with fluorescein isothiocyanate (FITC). The surface concentration of the Binding Domains adsorbed on cellulose fibres was determined by fluorescence image analysis.

Results

For a CBD-FITC concentration of 60 mg/L, a coating fraction of 78% and 110% was estimated for Portucel and Whatman fibres, respectively. For a saturating CBD concentration, using Whatman CF11 fibres, a surface concentration of 25.2 × 10^-13 mol/mm² was estimated, the equivalent to 4 protein monolayers. This result does not imply the existence of several adsorbed protein layers.

Conclusion

It was verified that CBDs were able to penetrate the fibres, according to confocal microscopy and TEM-immunolabelling analysis. The surface concentration of adsorbed CBDs was greater on amorphous fibres (phosphoric acid swollen) than on more crystalline ones (Whatman CF11 and Sigmacell 20).