Carbon-based nanomaterials have attracted significant attention in biomedical research due to their unique properties and versatility. PEGylation has been widely used to improve graphene oxide stability and reduce toxicity in vitro, with PEG-GO showing low cytotoxicity in lymphoma cells and enhanced colloidal behavior in biological media. However, studies also indicate that PEGylated composites can interact with endothelial models under pathophysiological conditions, and surface modifications influence cellular uptake and internalization patterns.

In this study, pegylated expanded graphene oxide (EGO-PEG) was synthesized from expanded graphene oxide (EGO) to evaluate the impact of PEG functionalization on cytotoxicity in human endothelial cells. Structural and morphological characterization was performed using Infrared Spectroscopy (IR), Raman Spectroscopy (RS), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Atomic Force Microscopy (AFM), confirming successful PEG conjugation through amide (NH–CO) bond formation.

Cytotoxicity was assessed in EA.hy926 endothelial cells cultured in DMEM, BSA, and FBS using the MTT assay. EGO-PEG exhibited reduced cytotoxicity and higher cell viability compared to non-pegylated EGO. However, no significant decrease in toxicity was observed in protein-rich media (FBS or BSA). TEM micrographs revealed EGO internalization within cytoplasmic vacuoles, indicating effective cellular uptake. Cell viability was primarily influenced by nanoparticle size, shape, and concentration, and intracellular EGO accumulation may contribute to mitochondrial dysfunction.

These findings demonstrate that PEG functionalization enhances the cytocompatibility of expanded graphene oxide, supporting its potential in nanomedical applications.