Synthesis of carbon nanodots from wine cork for the detection of ferrum (III) ions and bioimaging of onion epidermal cells

Abstract

In this study, we synthesised the carbon nanodots (CDs) from the waste wine cork using a hydrothermal method. The analysis results indicated the average diameter of CDs was 6.2±2.7 nm. The UV-vis absorption spectrum shows two peaks around 217 and 280 nm, which are attributed to π-π* transition and n-π* transition of the C=C and the C=O bonds, respectively. When changing the excitation wavelength from 340 to 500 nm, the luminescence peak of CDs also shifts simultaneously from 445 to 605 nm. This result indicated excitation-dependent photoluminescence of the obtained CDs. Based on the studied physicochemical properties, we used CDs to probe the ability of Fe³⁺ ions detection using fluorescence quenching. The estimated results revealed that the detection limit reached ~0.012 mg/ml. Besides, CDs have also been used to stain the onion epidermal cells. The onion cells exhibit fluorescence in green and red under violet (405 nm) and green (532 nm) laser diode excitation, respectively. The initial result shows the potential applications of CDs in the fields related to cell imaging and sensing.