Flavin Improves Physico-Mechanical Properties and Bioimaging Suitability of Surfactant-Supplemented Graphene...

Carbonaceous materials like graphene oxide (GO) have unique properties with tunable surface chemistry. This makes them widely acceptable in sensors, optoelectronics, and biomedical applications. However, the major bottleneck is their low solubility in aqueous media. In this work, we explore the potential of riboflavin as a dispersing agent by comparing it with conventional surfactants/dispersion agents like cationic cetyltrimethylammonium bromide (CTAB) and anionic sodium dodecyl sulfate (SDS). We used advanced modes of atomic force microscopy (AFM), such as tapping, electrical, and nanomechanical, to determine the change in the surface process of graphene with surfactant supplementation. In this work, we showed that riboflavin can alter the graphene's surface features, such as increasing roughness, altering electrical properties, and significantly inducing nanomechanical properties, paving the way for enhanced cellular uptake relevant for bioimaging applications. The bioimaging applications were explored with cancerous (HeLa) and noncancerous cells (HEK-293), which show significant uptake of flavin-dispersed samples with increased fluorescence intensity with the addition of SDS and CTAB as contrasting agents. Overall, the novelty of this study is utilizing biocompatible riboflavin as a good alternative to conventional surfactants for carbonaceous materials. Our study suggests that flavin-dispersed GO can be a potential fluorescence probe for real-time tracking of cellular processes.