Insights into Adsorption Characterization of Sulfated Xylans onto Poly(ethylene terephthalate)

Abstract

The main aim of this investigation was to study the interaction of sulfated xylans as antithrombotic substances with poly(ethylene terephthalate) (PET) model films as a model for blood contacting surfaces. The adsorption of sulfated xylans onto PET model films was studied as a function of pH and ionic strength using the quartz crystal microbalance with dissipation (QCM-D) technique. The application of positively charged polyethyleneimine (PEI) as an anchoring polymer was done to improve the adsorption. The hydrophilic/hydrophobic properties of functionalized PET surfaces were monitored by goniometry, whilst their elemental composition was determined by X-ray photoelectron spectroscopy. Sulfated xylans adsorbed favorably at pH 5 by physical interactions and by entropy gain driven adsorption. Higher ionic strengths of solutions improved adsorption, due to the reduction of electrostatic repulsive forces between PET surfaces and anionic xylans’ macromolecules. The intermediate PEI layer caused more extensive and stable adsorption due to Coulomb interactions. The surface modifications presented in this work provided important information regarding the adsorption/desorption phenomena between antithrombotic sulfated xylans and PET surfaces. The latter is of great interest when preparing advanced polymer composite material such as functional antithrombotic PET surfaces for blood-contacting medical devices and presents an extremely challenging research field.

Carboxymethylated and Sulfated Furcellaran from Furcellaria lumbricalis and Its Immobilization on PLA Scaffolds

“…However, the interaction between the negatively charged functionalities resulting from plasma-treated surfaces and the limited number of positively charged amino groups significantly influences the immobilization of furcellaran with negatively charged groups (sulfate/carboxymethyl). This dynamic results in enhanced repulsive forces between the PLA surface and sulfated/carboxymethylated furcellaran molecules, leading to decreased binding affinity and, consequently, poorer adsorption [ 66 ]. This phenomenon manifests as the formation of localized flocculated particles on the continuous PLA surface (as indicated in SEM micrographs), which may have unpredictable biological implications.…”

Synthesis of Birch Wood Xylan Sulfate in the Sulfamic Acid–Urea Melt

“…Hemicelluloses are found as organic wastes or by-products of renewable forest and agricultural products; however, unlike cellulose, they have not yet found wide industrial application. [2] Xylan constitutes 25-35 % of the dry biomass of woody tissues, e. g., birch wood. [3] Birch is widespread in the forests of the northern hemisphere, which makes it one of the most prominent future resources of xylan.…”

“…It is a type of hemicelluloses composed of the β‐1,4‐linked xylose (a pentose sugar) residue with side branches of α–glucuronic acids. Hemicelluloses are found as organic wastes or by‐products of renewable forest and agricultural products; however, unlike cellulose, they have not yet found wide industrial application [2] …”

Surface Chemistry of Polymers

“…Polyethylene terephthalate (PET) is sometimes used as a material for body implants such as vascular grafts and polymeric stents. Fras et al [ 8 ] studied the adsorption of sulfated xylans on PET polymers. No plasma pretreatment was performed, but the polymer was carefully cleaned.…”