Application of a Rhodamine-chromone Schiff base probe for the sensing of Fe3+, Al3+, Cr3+ at low concentration and exploration of the anticancer activity and bio-imaging

Abstract

Strategic design of fluorescent probe for the recognition of ions/molecules at very low concentration by fluorescence sensing is one of the stimulating current research topics with reference to health and sustainability. Towards this objective, Rhodamine based chemosensors are playing extraordinary protagonist. In this work, a Rhodamine appended chromone Schiff base (RFC), with two fluorogenic motifs, has been characterized through various spectroscopic techniques. The probe exhibits efficient sensitivity towards Analytical Group IIIA ions (Al3+, Cr3+ and Fe3+) in existence of other competitive analytes. The fluorescent intensity is enhanced by 350 fold (Fe3+), 250 fold (Al3+) and 220 fold (Cr3+), respectively in methanol-water (99:1,v/v; HEPES buffer, pH, 7.2) medium. The limits of detection (LOD) (3σ/M method; σ = standard deviation; M = slope) are 0.0051 ppm (Fe3+), 0.0029 ppm (Al3+) and 0.0052 ppm (Cr3+); which are impressive and much below the WHO recommended data. In addition to this, the compound has been utilized for cell imaging in presence of these three cations. The action of probe on MCF-7 (human breast cancer) cell lines demonstrates IC50, 2.53 µM that is far better than activity against WI-38 (normal cell line) (IC50, 393.7 µM). The drug (RFC) minimizes the cellular proliferation and has significant wound healing capacity of the infected tissue with MCF-7 cells. The probe shows significant nuclear fragmentation with increase in the expression of apoptotic markers. Growth inhibition analysis in 3D tumor spheroid model showed the inhibition of breast cancer MCF-7 cells.