A multianalyte fluorescent carbon dots sensing system constructed based on specific recognition of Fe(iii) ions

Abstract

In this research, we developed a multianalyte fluorescence sensing system through a carbon dots (CDs)-based fluorescent probe that can specifically recognize Fe(III) by fluorescence quenching. The CDs prepared using black tea by a hydrothermal method show outstanding properties like low cytotoxicity, high photostability, excellent biocompatibility, and high sensitivity. It was found that the fluorescence of CDs can be quenched by micromolar concentrations of Fe(III) in both aqueous solutions as well as living cells. It is well known that glucose can be oxidized by glucose oxidase (GOx) to release H 2 O 2 , which, in turn, can oxidize Fe(II) to Fe(III). Based on this consideration, a multianalyte sensing system was established. Therefore the quantitative analysis of Fe(III), H 2 O 2 , and glucose with detection limits of 0.25 mM, 0.82 mM, and 1.71 mM, respectively, was achieved by the simple and cost-effective multianalyte CDs sensing system constructed. The sensing system showed high photostability and negligible cytotoxicity toward HeLa cells, which enables it to be applied in the visualization of Fe(III) or H 2 O 2 in living cells. The system was further applied in the detection of Fe(III) or glucose in human serum, and satisfactory results were obtained.

Biomass‐Derived Carbon Dots and Their Applications

“…In addition to vegetables and fruits, there are a lot of biomass that can be used as a carbon source to prepare BCDs, for example, grass, ginkgo leaves, bamboo leaves and other plants, black tea, soy milk, and other beverages. BCDs prepared with these carbon sources have a good dispersion, and the size distribution is relatively uniform.…”

“…proposed to scale up the synthesis of BCDs by adopting bee pollen as a carbon source, with more than 3 g of BCDs produced from 10 g of bee pollen (Figure b). Black tea was taken as a carbon source and heated at 200 °C autoclave for 5 h to prepare BCDs. The average diameter of the BCDs prepared was about 4.6 nm.…”

“…The UV‐visible spectrum of BCDs typically has its highest peak in the ultraviolet region. The UV absorption peak of BCDs is usually located between 230∼270 and 300∼330 nm, and the absorption at 230–270 nm is usually due to the π−π* transition, while the absorption at 300–330 nm is usually due to the n−π* transition . BCDs from silkworm chrysalis due to the aromatic sp 2 domain of π−π* conversion, so there is absorption at 276 nm, as well, due to the n−π* conversion of C=O bonds, so there is absorption at 317 nm, and a tail extends to the visible range.…”

“…BCDs from silkworm chrysalis due to the aromatic sp 2 domain of π−π* conversion, so there is absorption at 276 nm, as well, due to the n−π* conversion of C=O bonds, so there is absorption at 317 nm, and a tail extends to the visible range. The UV‐Vis spectra of black tea BCDs show two absorption peaks, one at 270 nm and one at 320 nm, which are due to a π−π* transition of C=C bonds and the n−π* transition of C=O bonds in BCDs, respectively. The UV‐Vis spectrum of soy milk BCDs shows a narrow peak at 275 nm due to the π−π* transition of the nanocarbon.…”

“…The wavelength‐tuned emission in the prepared BCDs was attributed to the optical selection of surface defect states near Fermi level. Song et al . prepared BCDs from black tea and studied its optical properties.…”