The anion of choline-based ionic liquids tailored interactions between ionic liquids and bovine serum albumin, MCF-7 cells, and bacteria

Choline-based ionic liquids (ILs) have been widely applied because of their good biocompatibility. Herein, the toxicity of choline-based ILs containing different anions was studied by UV-vis absorption spectra, fluorescence spectra, MTT assays and antibacterial experiments. The results explained that choline chloride ([Ch][Cl]) had no obvious effect on the conformation of bovine serum albumin (BSA), while the conformation could be slightly changed by choline bromide ([Ch][Br]). In the presence of choline iodide ([Ch][I]), choline bitartrate ([Ch][Bit]) and choline dihydrogen citrate ([Ch][Dhc]), the conformation of BSA changed significantly. The quenching mechanisms of [Ch][Bit] and [Ch][Dhc] were static quenching procedure, while there were charge transfer quenching and static quenching for [Ch][I]. ILs combined with BSA in spontaneous manner driven by hydrogen bond and van der Waals force, which was proved by thermodynamic constants and molecular docking. The toxicity of the five ILs to mammalian cells and bacteria came to a similar conclusion. [Ch][Cl] had little toxicity to cells, which was less than [Ch][Br] and [Ch][I]. [Ch][Bit] and [Ch][Dhc] were more toxic. These results provide more information to understand the effect of anions on choline-based ILs, in order to find low toxic choline-based ILs that can be used in biological and pharmaceutical fields.

Automated summary

Choline-based ionic liquids with different anions were studied for their toxicity, revealing that choline chloride had minimal toxicity, while choline bitartrate and choline dihydrogen citrate showed higher toxicity to cells.