Antimicrobial graphene nanoplatelets coatings for silicone catheters

Silicone rubber (SR) peritoneal dialysis (PD) catheters are prone to bacterial adhesion and biofllm formation, which contributes to development of infection and associated morbidity in PD patients. We herein evaluate whether surface immobilization of graphene nanoplatelets (GNP) provides antimicrobial properties to SR. Dip and spray coating were used to deposit a dispersion containing SR and GNP-M5 or its oxidized form (GNP-M5ox) on the surface of silicone. The antimicrobial effect of GNP exposure and oxidation towards Staphylococcus epidermidis was assessed. GNP was successfully exposed on the surface, and while dipping provided better adhesion of either GNP, spraying resulted in uniform and higher surface coverage. Spraying led to enhanced bacterial adhesion comparing to dip coated and uncoated SR, which are similar. However, independently of the technique, GNP-M5ox coatings induced higher bacterial death. As such, SR/GNP-M5ox coating performed by dipping revealed to be the most promising approach, preserving bacterial adhesion levels of silicone while increasing bacterial death to around 80%. For the first time, graphene-based materials antimicrobial activity was evaluated by quantification of bacterial adhesion and viability. The high antibacterial effect, associated with a stable and cytocompatible coating which does not delaminate from SR surface, demonstrates its potential use in silicone biomedical industry. (C) 2018 Elsevier Ltd. All rights reserved.