Galactose grafting on poly(ε-caprolactone) substrates for tissue engineering: A preliminary study

The grafting of galactose units onto poly(ε-caprolactone) (PCL) substrates by a wet chemistry two-step procedure is proposed. Even though a reduction of hardness from 0.58-0.31 GPa to 0.12-0.05 GPa is achieved, the chemical functionalization does not negatively affect the tensile modulus (332.2 ± 31.3 MPa and 328.5 ± 34.7 MPa for unmodified and surface-modified PCL, respectively) and strength (15.1 ± 1.3 MPa and 14.8 ± 1.5 MPa as assessed before and after the surface modification, respectively), as well as the mechanical behaviour evaluated through small punch test. XPS and enzyme-linked lectin assay (ELLA) demonstrate the presence, and also the correct exposition of the saccharidic epitope on PCL substrates. The introduction of carbohydrate moieties on the PCL surfaces clearly enhances the hydrophilicity of the substrate, as the water contact angle decreases from 82.1 ± 5.8° to 62.1 ± 4.2°. Furthermore, preliminary biological analysis shows human mesenchymal stem cell viability over time and an improvement of cell adhesion and spreading.