Novel Technology of Modifying the Surface of Biodegradable Vascular Grafts with RGD Peptides: Effect on the Surface Structure and Physical and Mechanical Properties

Abstract

The aim of the study was to assess the effectiveness of a new technology of modifying biodegradable small-diameter vascular grafts from polyhydroxybutyrate/valerate (PHBV) and polycaprolactone (PCL) with RGD peptides and its effect on the surface structure and physical and mechanical characteristics of these grafts. Materials and Methods. Tubular polymer prostheses (matrices, grafts) 1.5 mm in diameter were fabricated using electrospinning method from the composition of PHBV and PCL polymers. Hexamethylendiamine, glutaraldehyde, ascorbic acid, and arginine-glycineaspartic acid were used to modify the surface of polymer scaffolds. The quality of the modification performed was assessed using a ninhydrin test and by determining the arginine-containing peptide. The structure of the graft surfaces before and after modification was examined using scanning electron microscopy. Mechanical properties were evaluated by uniaxial tension with determination of ultimate tensile strength, relative elongation, and Young's modulus. The characteristics of the internal mammary artery (a. mammaria interna) were used as a control of these parameters, vascular synthetic ePTFE-based linear grafts served as a group of comparison. Results. Presence of RGD peptides on the polymer surface was confirmed by a Sakaguchi test which is specific for arginine. The mode of modification did not alter the surface structure of the polymer grafts but resulted in the reduction of their rigidity by 1.6 times, strength by 3.9 times, and relative elongation by 1.7 times. The physical and mechanical properties of PHBV/PCL+RGD grafts approached those of the a. mammaria. Conclusion. The developed technology of modifying the surfaces of PHBV/PCL-based vascular grafts with RGD peptides made it possible to obtain PHBV/PCL+RGD grafts with the physical and mechanical properties approaching to those of the native vessels without any changes of the surface structure.