Synthesis and characterization of a rhodamine derivative as a selective switch-on fluorescent sensor for Cu2+ ions in aqueous PBS buffer and living cells†
Abstract
A novel rhodamine-based receptor molecule (L1) was synthesized via the reaction between rhodamine hydrazide and acetylacetone. Several spectroscopic methods, viz., FTIR spectroscopy, 1H NMR and 13C NMR, and ESI-MS, were used to characterize the receptor molecule (L1). The L1 demonstrated turn-on response towards Cu2+ ions out of 18 different metal ions studied in an aqueous buffer at pH 7.4 with a minimum detection limit of 3.58 × 10−8 M. The binding interaction between L1 and Cu2+ ions was shown by absorbance studies, wherein isosbestic points were observed at 286 and 329 nm. Job's plots indicate the formation of a 1 : 1 complex between L1 and Cu2+ ions. Additionally, DFT simulations show a strong interaction between the Cu2+ ions and the receptor L1, and TD-DFT investigations show an optical absorption shift in favor of a longer wavelength in the {L1 + Cu2+} complex. Further, the biological applicability of L1 for the in vitro detection of Cu2+ ions in L929 and HeLa living cells was demonstrated. These findings illustrated that L1 could be used to detect Cu2+ ions in environmental and biologically relevant media.
- This article is part of the themed collection: Functional Nanomaterials for Diagnostic Applications