Doped graphene oxide functionalization strategy for synthesis of nanocomposite membranes: electrospun coatings in biomedical field application

An electrospun membrane for vascular stent coating made of 2-methacryloyloxyethyl phosphorylcholine and butyl methacrylate copolymer (MPC-co-BMA), also known as (PMB), reinforced with functionalized and nitrogen doped reduced graphene oxide (f-NrGO) is presented. This membrane due to the nitrogen doped reduced graphene oxide (NrGO) negative electric charge has the capacity to repeal low density lipoproteins (LDL), which under specific conditions are the main cause of atherosclerotic disease. The NrGO functionalization process is detailed, as it creates strong bonds between NrGO and PMB, avoiding NrGO sheets to detach from the membrane. The copolymer synthesis was characterized by FTIR and chemical bonds between f-NrGO and PMB were proved by XPS and HNMR. Additionally, a simplified test bank that simulates blood flow conditions demonstrated the NrGO functionalization effect over the membrane. For the electrospinning process, optimal parameters were a voltage of 14.5 kV, and a flow rate of 0.3 mL/h, which lead to better properties of the membrane for the application. DMA results confirmed that the best reinforcement percentage of f-NrGO in terms of mechanical properties was 0.1 wt% and AFM images indicated the presence of the f-NrGO sheets over the fibers. Finally, the contact angle revealed the repulsion response to LDL, such behavior is promising to applications like cardiovascular coated stents.