High-yield graphene produced from the synergistic effect of inflated temperature and gelatin offers high stability and cellular compatibility†
The direct exfoliation of graphite (Gr) is highly desirable and feasible compared to conventional processes owing to its non-oxidative, facile and controlled synthesis conditions. Herein, gelatin (gel), a hydrolysed form of collagen, was used as an exfoliant to directly exfoliate Gr. The main advantages of exploring gel as an exfoliant is its easy availability, low cost and high biocompatibility, which alleviate the drawbacks of previous exfoliation methods. The effect of the exfoliation parameters such as temperature, ratio of interacting species and pH of the solution offers a high yield of graphene (G) with the added advantages of good solubility, easy dispersibility and high stability. The temperature elevation caused by the dissipation of sonic waves facilitates a high exfoliation yield. Yield of 4.37 mg mL−1 of G was achieved under the conditions of 7 h sonication at 60 °C, pH 7 and Gr to gel ratio of 60 : 40, whereas yield of 1 mg mL−1 was achieved under sonication at 30 °C. Raman spectroscopy and transmission electron microscopy indicated the production of G sheets with 3–5 layers. The adsorption of gel on the surface of G via π–π interactions offers high stability and retains its inherent crystallinity. The as-synthesized G dispersion exhibits good cyto- and hemocompatibility. Unlike graphene oxide, the G dispersion does not affect RBCs at a relatively high concentration of 10 mg mL−1. These findings offer new avenues for the large-scale production of G and promote its biomedical applications, particularly in scaffold materials and intravenous drug delivery.