Endothelial cell responses to castor oil-based polyurethane substrates functionalized by direct laser ablation

Abstract

Surface-induced thrombosis and lack of endothelialization are major drawbacks that hamper the widespread application of polyurethanes for the fabrication of implantable cardiovascular devices. Endothelialization of the blood-contacting surfaces of these devices may avoid thrombus formation and may be implemented by strategies that introduce micro and submicron patterns that favor adhesion and growth of endothelial cells. In this study, we used laser radiation to directly introduce topographical patterns in the low micrometer range on castor oil-based polyurethane, which is currently employed to fabricate cardiovascular devices. We have investigated cell adhesion, proliferation, morphology and alignment in response to these topographies. Reported results show that line-like and pillar-like patterns improved adhesion and proliferation rate of cultured endothelial cells. The line-like pattern with 1 μm groove periodicity was the most efficient to enhance cell adhesion and induced marked polarization and alignment. Our study suggests the viability of using laser radiation to functionalize PU-based implants by the introduction of specific microtopography to facilitate the development of a functional endothelium on target surfaces.

Why Polyurethanes Have Been Used in the Manufacture and Design of Cardiovascular Devices: A Systematic Review

“…Four of the studies were conducted in the USA [ 7 , 8 , 9 , 10 ], three in Italy [ 11 , 12 , 13 ], two each in India [ 14 , 15 ] and Iran [ 16 , 17 ], and one each in Australia [ 18 ], Canada [ 19 ], Colombia [ 20 ], Germany [ 3 ], South Korea [ 21 ], and Taiwan [ 22 ]. The collaborative studies that were conducted are as follows: Australia–France [ 23 ], Brazil–Germany [ 2 ]; and People’s Republic of China–Canada [ 24 , 25 ].…”

“…Seventeen studies conducted in vivo tests with NIH/3T3 mouse fibroblast cell line [ 11 ], human umbilical vein endothelial cell (HUVEC) [ 2 , 14 , 16 , 23 , 25 ], L-929 fibroblast [ 16 , 20 , 22 ]; 3T3 [ 18 , 20 ], H9C2 cardiomyoblasts [ 12 ], endothelial colony forming cells (ECFCs) [ 3 ], smooth muscle cells (SMCs) [ 15 ], A10 SMCs [ 19 ], ECs [ 15 ], human microvascular endothelial cells (HMEC) [ 21 ], cardiomyocytes [ 13 ], or hBMSCs [ 17 ]. Two studies performed both in vivo and in vitro tests [ 7 , 9 ].…”

“…Six studies presented variations of the chemical compositions of PUs [ 11 , 15 , 16 , 17 , 20 , 24 ]. Five studies presented modifications to the material surface [ 7 , 9 , 14 , 21 , 23 ] and ten studies described different techniques to prepare PUs [ 2 , 3 , 8 , 10 , 12 , 13 , 18 , 19 , 22 , 25 ].…”

“…However, studies reported that PUs show severe problems [ 22 ] when applied in blood-contacting devices, such as the biodegradation that occurs during long-term implantation [ 29 ] by the adhesion of inflammatory cells [ 27 ], surface-induced thrombosis [ 2 , 22 ], and protein fouling [ 22 ] (which are known to participate in PU biodegradation); and the absence of endothelialization [ 2 ].…”

“…These medical-grade PUs are potential materials for long-term implantation within a living body as “minimally invasive devices” because of their inherent properties, including having a low modulus of elasticity and high ultimate tensile strength [ 1 ]. It is established that the synthetic materials used for biomedical applications require remarkable mechanical properties, including blood compatibility, good biostability [ 2 ] and hemocompatibility, and the capability to minimize adverse rejection processes mediated by adhering cells or proteins [ 3 ].…”