Carbon dots derived from Fusobacterium nucleatum for intracellular determination of Fe ³⁺ and bioimaging both in vitro and in vivo

Abstract

Fusobacterium nucleatum has been employed for the first time to synthesize fluorescent carbon dots which could be applied for the determination of Fe ³⁺ ions in living cells and bioimaging in vitro and in vivo with excellent biocompatibility.

Abstract

Intracellular Fe ³⁺ amount is one of the critical determinants of human health. The development of simple and effective probes for the quantitative detection of Fe ³⁺ in vivo is of great significance for the early diagnosis of disease or disorder associated with iron deficiency or overload. In this study, remarkable carbon dots, which can serve as a biosensor for efficient intracellular Fe ³⁺ detection, were synthesized by hydrothermal carbonization of Fusobacterium nucleatum, an anaerobic bacterium. The achieved F. nucleatum-carbon dots (Fn-CDs) possessed the features of strong fluorescence, high stability and excellent biocompatibility. The obtained Fn-CDs could easily internalize into both plant cells and human cells with excellent ability for cell tracking and biomedical labeling. The fluorescence of Fn-CDs could still remain for another 24 hours after penetrating into cells. Furthermore, the fluorescent Fn-CDs were very sensitive to the presence of Fe ³⁺ ions even in cells, exhibiting great promising applications in in vivo detection of Fe ³⁺ ions. In addition, the Fn-CDs posed no harm to the mice, being circulated and excreted within a short time, making the Fn-CDs an excellent candidate for bioimaging and biosensing in vivo.