Blood protein adsorption on sulfonated chitosan and κ-carrageenan films

• BSA and fibrinogen adsorption on sulfonated and κ-carrageenan films was investigated.
• Carrageenan has sulfate groups and has not been studied for blood applications.
• The chemical modification on chitosan chain reduced the fibrinogen adsorption.
• These biopolymers could be very promising candidates for blood medical devices.

Many strategies have been reported to improve compatibility of biopolymers using chemical and physical modifications. One possibility is the introduction of sulfonate groups (R-SO3−) in the chitosan chain. Another biopolymer with similar characteristics to those of heparin is κ-carrageenan. This study proposed to investigate the application of these two polymers, based on their potential for globular protein adsorption (BSA and fibrinogen). Polymeric films of chitosan and κ-carrageenan were prepared; all films were characterized by elemental analyses, FTIR, XPS and SEM. Characterization techniques showed that the chitosan chain was modified and confirmed the existence of sulfonate groups, as well as in the κ-carrageenan chain, indicating surfaces with similar chemical properties to those of heparin. The effect of charge density was observed for each adsorption condition (BSA at pH 5.0 and 7.4). A more pronounced adsorption rate was observed at pH 5.0 than at pH 7.4 and equilibrium adsorption was achieved, in both cases, after approximately 20 min. The equilibrium data indicate a lower adsorption rate for the sulfonated chitosan film, in comparison to the other films. These results confirm the potential of modified chitosan for use in applications in which globular protein adsorption should be avoided.

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