Adsorption of Fucoidan and Chitosan Sulfate on Chitosan Modified PET Films Monitored by QCM-D

Abstract

The adsorption behavior of fucoidan as well as chitosan derivatives (chitosan sulfate) on poly(ethylene terephthalate) (PET) model film surface was studied using the quartz crystal microbalance technique. These systems were chosen for this study due to their promising biocompatible properties. Moreover, fucoidan and chitosan sulfate have promising anticoagulant properties and represent an alternative to heparin treatment of vascular grafts. As a first step, PET foils were activated by alkaline hydrolysis to increase their hydrophilicity. From these foils, model PET films were prepared by the spin coating technique on a silica quartz crystal. The selected polysaccharides (chitosan, fucoidan, and chitosan sulfate) were adsorbed from aqueous solutions on the PET surfaces. The adsorption was monitored using a quartz crystal microbalance with a dissipation unit. The surface chemistry and morphology of the chitosan/fucoidan or chitosan/chitosan sulfate coated PET-H films was analyzed using XPS and AFM. It was found that chitosan/fucoidan films were thinner and more compressed, while in the case of chitosan/chitosan sulfate, large amounts of chitosan sulfate were adsorbed, indicating a loose and thick adsorbed film.

Semi‐Synthetic Polysaccharide Sulfates as Anticoagulant Coatings for PET, 1 – Cellulose Sulfate

“…It has been reported that chitosan (Ch) can improve the binding of sulfated polysaccharides. [14] However, chitosan is isolated from different natural sources (e.g., crab or squid shells) and may differ in its degree of N-acetylation, MW, and the amount of protein residues. [18] Thus, 6-deoxy-6-aminocelluloses were tested as anchor layers in the present study as well.…”

“…Although the present study involved only a single adsorption step and fucoidan containing films have been prepared by multiple adsorption of the polysaccharide on chitosan-coated PET films, the final shift factors were in a similar range (fucoidan: DF % -17 Hz, CS: DF % -19-29 Hz). [14] In the later case, most of the additionally attached fucoidan multilayers have been removed by the final rinsing step while only a small frequency increase by polysaccharide desorption was observed for rinsing of CScoated films. This finding leads to the assumption that CS and fucoidan are adsorbed to PS-NH 2 -coated PET films in a comparable way.…”

“…This procedure was optimized as already described in literature. [14,28] From the equilibrium stages before polysaccharide adsorption and after NaCl rinsing the final shift values (DF, DD Â 10 À6 ) for each adsorption step were taken, which allowed quantitative analysis ( Table 2) PS-NH 2 layers are rather stiff and strongly fixed to the PET surface.…”

“…In contrast to that, multiple adsorption of chitosan sulfate indeed resulted in the formation of polysaccharide multilayers that could not be removed by rinsing. [14] Precipitation instead of equilibrium adsorption has been proposed in this case.…”

“…The products were adsorbed onto PET surfaces previously coated with different aminogroup-containing polysaccharides (PS-NH 2 ), in order to improve the binding. [14] A quartz crystal microbalance with dissipation monitoring (QCM-D) was used to study the adsorption behavior with respect to the effect of different anchor layers and the amount of sulfate groups. Subsequently the morphology and blood compatibility of CScoated PET foils were studied using atomic force microscopy (AFM) and ''clotting time determination''.…”