Highly selective zinc(II) triggered “Turn-ON” [5]helicene-based fluorescence sensor: Its application in liver and brain cells imaging

Abstract

A novel fluorescence sensor (MT) was successfully designed and synthesized based on a [5]helicene derivative bearing tris(2-pyridylmethyl)amine as a selective zinc ion (Zn2+) recognition. MT allowed a favorable Zn2+-triggered “turn-on” hypsochromic fluorescence response through the intramolecular charge transfer process. The limit of detection of MT was 29 nM (1.91 ppb), which was considerably below the limit recommended by the World Health Organisation for the amount of Zn2+ in drinking water (76 μM). MT showed an excellent selectivity toward Zn2+ in HEPES buffer: MeOH (5 mM, pH 7.2, 3:2) over other competitive metal ions through a fluorogenic color change from orange to blue, which was easily observed with the naked-eye. The good fluorogenic sensing of the Zn2+ probe helped to determine a small amount of Zn2+ in practical utilization such as a Zn2+-marking agent for intracellular applications in human hepatoma (HepG2) and glioblastoma astrocytoma (U251) cells.