Graphene-based materials: the key for the successful application of pHEMA as a blood-contacting device
Andreia T. Pereira, Andreia T. Pereira, Patrícia C. Henriques, Karl H. Schneider, Ana L. Pires, André M. Pereira, André M. Pereira, M. Cristina L. Martins, Fernão D. Magalhães, Helga Bergmeister, Inês C. Gonçalves
Abstract
Thrombosis and infection are the leading causes of blood-contacting device (BCD) failure, mainly due to the poor performance of existing biomaterials. Poly(2-hydroxyethyl methacrylate) (pHEMA) has excellent hemocompatibility but the weak mechanical properties impair its use as a bulk material for BCD. As such, pHEMA has been explored as a coating, despite the instability and difficulty of attachment to the underlying polymer compromise its success. This work describes the hydrogel composites made of pHEMA and graphene-based materials (GBM) that meet the biological and mechanical requirements for a stand-alone BCD. Five GBM differing in thickness, oxidation degree, and lateral size were incorporated in pHEMA, revealing that only oxidized-GBM can reinforce pHEMA. pHEMA/oxidized-GBM composites are cytocompatible and prevent the adhesion of endothelial cells, blood platelets, and bacteria (S. aureus), thus maintaining pHEMA's anti-adhesive properties. As a proof of concept, the thrombogenicity of the tubular prototypes of the best formulation (pHEMA/Graphene oxide (GO)) was evaluated in vivo, using a porcine arteriovenous-shunt model. pHEMA/GO conduits withstand the blood pressure and exhibit negligible adhesion of blood components, revealing better hemocompatibility than ePTFE, a commercial material for vascular access. Our findings reveal pHEMA/GO, a synthetic and off-the-shelf hydrogel, as a preeminent material for the design of blood-contacting devices that prevent thrombosis and bacterial adhesion.