Heparinization of the bovine pericardial scaffold by layer-by-layer (LBL) assembly technique

Abstract

The bovine pericardium has been introduced to tissue engineering as a highly versatile material. Bovine pericardial scaffolds (BPSs) have been fabricated and presented good mechanical properties and biocompatibility. In the cardiovascular field, thrombogenicity is the main obstacle limiting the effectiveness of BPSs due to thrombus formation. Heparinization is a potential approach to improve the hemocompatibility of engineered constructs derived from decellularized tissues. In this study, we report on BPSs heparinized by the Layer-by-Layer self-assembly (LbL) technique. Heparin was immobilized on BPSc by introducing linkage of heparin and dihydroxy-iron (DHI). The oppositely charged heparin and DHI were alternatively deposited on the surface of BPSc microfibers via the desired number of LbL cycles. Hematoxyline and eosin (H&E) staining, scanning electron microscopy (SEM), and Toluidine Blue O (TBO) assay were used to evaluate the morphology and efficacy of heparinized BPSs. The anticoagulant activity was assessed by incubating the tested materials with blood. Histological evidence indicated the heparin deposition when increasing the number of LbL cycles. SEM observations revealed Heparin-DHI complex coatings onto the microfibrils of the scaffold. In comparison with simple incubation, more heparin molecules are effectively linked to the scaffolds when using the LbL technique in the presence of DHI. Heparin contents in the BPS samples significantly varied with the number of LbL cycles. The heparinized membranes exhibited the resistance to blood clotting upon blood-contacting. Furthermore, heparin-DHI multilayer coating was shown to maintain good anticoagulation activity over a 30-day release period. Finding results verified the successful heparinization of the BPSs by the Layer-by-Layer self-assembly technique. The heparinized bovine pericardial scaffolds could be valuable candidate material in the cardiovascular field.

Keywords

• Extracellular matrix
• Scaffold
• Decellularization
• Heparin
• Layer-by-layer assembly
• Multilayer