Poly(ethylmethacrylate-co-diethylaminoethyl acrylate) coating improves endothelial re-population, bio-mechanical and anti-thrombogenic properties of decellularized carotid arteries for blood vessel replacement

Decellularized vascular scaffolds are promising materials for vessel replacements. However, despite the natural origin of decellularized vessels, issues such as biomechanical incompatibility, immunogenicity risks and the hazards of thrombus formation, still need to be addressed. In this study, we coated decellularized vessels obtained from porcine carotid arteries with poly (ethylmethacrylate-co-diethylaminoethylacrylate) (8g7) with the purpose of improving endothelial coverage and minimizing platelet attachment while enhancing the mechanical properties of the decellularized vascular scaffolds. The polymer facilitated binding of endothelial cells (ECs) with high affinity and also induced endothelial cell capillary tube formation. In addition, platelets showed reduced adhesion on the polymer under flow conditions. Moreover, the coating of the decellularized arteries improved biomechanical properties by increasing its tensile strength and load. In addition, after 5 days in culture, ECs seeded on the luminal surface of 8g7-coated decellularized arteries showed good regeneration of the endothelium. Overall, this study shows that polymer coating of decellularized vessels provides a new strategy to improve re-endothelialization of vascular grafts, maintaining or enhancing mechanical properties while reducing the risk of thrombogenesis. These results could have potential applications in improving tissue-engineered vascular grafts for cardiovascular therapies with small caliber vessels

Dextran-based Hydrogel Layers for Biosensors

Biofunctional coatings are key elements of biosensors regulating interactions between the sensing surface and analytes as well as matrix components of the sample. These coatings can improve sensing capabilities both by amplifying the target signal and attenuating interfering signals originating from surface fouling (non-specific binding). Considering the tested materials so far, hydrogel-based layers have been verified to be among the most effective layers in improving biochip performance. The polysaccharide dextran can be efficiently used to form hydrogel layers displaying extended three-dimensional structure on biosensor surfaces. Owing to their high water content and flexible structure, dextran coatings present advanced antifouling abilities, which can be exploited in classic bioanalytical measurements as well as in the development of cell-on-a-chip type biosensors. However, in spite of the numerous applications, the deep characterization of dextran layers has been missing from the literature. This phenomenon can be attributed to the challenging analysis of few nanometer-thick layers with high water content. The lack of available data is more pronounced regarding the layer behaviors under aqueous conditions. In this chapter we present various surface analytical methods (including biosensor-type techniques) suitable for the complex characterization of hydrogel coatings whose thickness ranges from few to several ten nanometers. As a case study, we focus on the analysis of carboxymethyl dextran (CMD) layers developed for waveguide-based label-free optical biosensor applications. Examination methodologies both under dry and aqueous conditions as well as testing of antifouling abilities are also presented