Highly fluorescent carbon dots as selective and sensitive “on-off-on” probes for iron(III) ion and apoferritin detection and imaging in living cells

• Published in: Biosensors & bioelectronics 2016-09, Vol.83, p.229-236
• Main Authors: Han, Cuiping, Wang, Ru, Wang, Keying, Xu, Huiting, Sui, Meirong, Li, Jingjing, Xu, Kai
• Format: Article
• Language: English
• Subjects: Apoferritin; Apoferritins - analysis; Biotechnology; Carbon; Carbon - chemistry; Carbon dots; Cations - analysis; Cell Line; Cells (biology); Fluorescence; Fluorescent Dyes - chemistry; Humans; Imaging; Iron - analysis; Iron(III); Limit of Detection; Nanoparticles; On-off-on; Optical Imaging - methods; Quantum Dots - chemistry; Quenching (cooling); Sensing; Spectrometry, Fluorescence - methods; Ureas
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2016.04.066

Highly blue luminescent nitrogen-doped carbon dots (N-CDs) with a fluorescence quantum yield of 42.3% were prepared by an efficient one-step pyrolytic route from ethylenediaminetetraacetic acid and urea. The as-synthesized N-CDs were demonstrated as an effective fluorescent probe for label-free, selective and sensitive recognition of Fe3+ with a linear range of 0.5μM to 2mM and a detection limit of 13.6nM due to Fe3+-quenched fluorescence (turn-off). The quenched fluorescence could be turned on after the addition of apoferritin owing to the removal of ferric species from the surface of N-CDs by apoferritin, making complex N-CDs/Fe3+ a selective apoferritin probe with a linear range of 0.1–25μM and a detection limit as low as 2.6nM. In addition, the application of this novel N-CDs-based probe for imaging Fe3+ ions and apoferritin in living cells suggest that this sensing system has great potential applications in biosensing, bioimaging, and many other fields. •Highly luminescent N-doped carbon dots were prepared by an efficient one-step pyrolytic route.•Sensitive and selective sensing of Fe3+ and apoferritin was achieved.•The mechanism of the Fe3+ and apoferritin sensing was studied.•The probe is applied to fluorescence imaging for cellular Fe3+ and apoferritin successfully.