Effect of amino-terminated substrates onto surface properties of cellulose esters and their interaction with lectins

Films of cellulose acetate butyrate (CAB) and carboxymethylcellulose acetate butyrate (CMCAB) were deposited from ethyl acetate solutions onto bare silicon wafers (Si/SiO₂) or amino-terminated surfaces (APS) by means of equilibrium adsorption. All surfaces were characterized by means of ellipsometry, atomic force microscopy (AFM) and contact angle measurements. The presence of amino groups on the support surface favored the adsorption of CAB and CMCAB, inducing the orientation of most polar groups to the surface and the exposition of alkyl group to the air. Such molecular orientation caused increase of the dispersive component of surface energy (γ_s^d) and decrease of the polar component of surface energy (γ_s^p) of cellulose esters in comparison to those values determined for films deposited onto bare Si/SiO₂ wafers. Adsorption behavior of jacalin or concanavalin A onto CAB and CMCAB films was also investigated. The adsorbed amounts of lectins were more pronounced on cellulose esters with high (γ_s^p) and total surface energy (γ_s^t) values.