Highly selective fluorescent turn-on–off sensing of OH−, Al3+ and Fe3+ ions by tuning ESIPT in metal organic frameworks and mitochondria targeted bio-imaging. Issue 45 (16th August 2021)

• Record Type: Journal Article
• Authors: Bhowal, Soumya; Ghosh, Arijit
• Is Part Of: RSC advances. Volume 11:Issue 45(2021)
• Page Start: 27787
• Page End: 27800
• Publication Date: 2021-08-16
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d1ra03078g
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : ESIPT tuned fluorescence sensing of OH −, Al 3+ and Fe 3+ ions and mitochondria targeted bio-imaging by a Zn-DHNDC MOF. Abstract : Herein we report a multifunctional high performance metal organic framework (Zn-DHNDC MOF) based chemosensor that displays an exceptional excited state intramolecular proton transfer (ESIPT) tuned fluorescence turn-on–off response for OH −, Al 3+ and Fe 3+ ions along with mitochondria targeted bio-imaging. Properly tuning ESIPT as well as the hydroxyl group (–OH) allows Zn-DHNDC MOF to optimize and establish chelation enhanced fluorescence (CHEF) and chelation enhanced quenching (CHEQ) based sensing mechanisms. The MOF benefits from acid-base interactions with the ions which generate a turn-on bluish green fluorescence ( λ Em 492 nm) for OH −, an intense turn-on green fluorescence ( λ Em 528 nm) for Al 3+ and a turn-off fluorescence quenching response for Fe 3+ ions. The aromatic –OH group indeed plays its part in triggering CHEF and CHEQ processes responsible for the turn-on-off events. Low limits of detection (48 nM of OH −, 95 nM for Al 3+, 33 nM for Fe 3+ ions), high recyclability and fast response time (8 seconds) further assist the MOF to implement an accurate quantitative sensing strategy for OH −, Al 3+ and Fe 3+ ions. The study further demonstrates the MOF's behaviour in cellular medium by subjecting it to live cell confocal microscopy. Along with a bio-compatible nature the MOF exhibited successful accumulation inside the mitochondria of MCF7 cancer cells, which defines it as a significant bio-marker. Therefore the present work successfully represents the multidisciplinary nature of Zn-DHNDC MOFs, primarily in sensing and biomedical studies.