A fluorometric and colorimetric dual-mode sensor based on nitrogen and iron co-doped graphene quantum dots for detection of ferric ions in biological fluids and cellular imaging

N, Fe co-doped graphene quantum dots (N, Fe-GQDs) with excellent fluorescence performance were prepared by a simple one-pot hydrothermal method. During this process a dual doping strategy with chelated metal ions in combination with nitrogen passivation was developed. With this strategy, introducing Fe and retaining more oxygen-containing groups by chelation, in conjunction with N passivation, led to a dramatic enhancement of photoluminescence for N, Fe-GQDs. Furthermore, a fluorometric and colorimetric dual mode nanosensor based on the N, Fe-GQDs was prepared for effective and selective detecting of Fe3+ ions. More significantly, it was found that the as-prepared N, Fe-GQDs can be applied to detection of Fe3+ ions in biological samples and cellular imaging, which has a huge potential for utilization in practical applications.