Aggregation‐induced emission enhancement of anthracene‐derived Schiff base compounds and their application as a sensor for bovine serum albumin and optical cell imaging

• Published in: Luminescence (Chichester, England) Vol. 33; no. 4; pp. 780 - 789
• Main Authors: Densil, Simon, Chang, Chien‐Huei, Chen, Chia‐Ling, Mathavan, Alagarsamy, Ramdass, Arumugam, Sathish, Veerasamy, Thanasekaran, Pounraj, Li, Wen‐Shan, Rajagopal, Seenivasan
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.06.2018
• Subjects: Agglomeration; Aggregation; aggregation‐induced emission enhancement; Anthracene; anthracene‐based Schiff base; Atomic force microscopy; biosensor; Bovine serum albumin; Breast cancer; BSA; C=N isomerization; Cancer; Conjugation; Electron microscopy; Emission; Fluorescence; Fluorescent indicators; Imaging techniques; Imines; Isomerization; Methylene; Microscopy; optical imaging; Scanning electron microscopy; Serum; Serum albumin; Tetrahydrofuran; BSA; anthracene-based Schiff base; biosensor; aggregation-induced emission enhancement; optical imaging; C=N isomerization
• ISSN: 1522-7235; 1522-7243
• DOI: 10.1002/bio.3477

Three anthracene‐based Schiff base complexes, R1–R3 (R1 = (E)‐N´‐((anthracen‐10‐yl)methylene)benzohydrazide; R2 = (E)‐1‐((anthracen‐10‐yl)methylene)‐4‐phenylsemicarbazide; and R3 = (E)‐1‐((anthracen‐10‐yl)methylene)‐4‐phenylthiosemicarbazide) were synthesized from 9‐anthracenecarboxaldehyde, benzohydrazide, 4‐phenylsemicarbazide and 4‐phenylthiosemi‐carbazide respectively, and characterized by various spectral techniques. The absorption spectral characteristics of R1–R3 were bathochromically tuned to the visible region by extending the π conjugation. These target compounds were weakly fluorescent in tetrahydrofuran (THF) solution because of rapid isomerization of the C=N double bond in the excited state. However, the aqueous dispersion of R1–R3 in the THF/water mixture by the gradual addition of water up to 90% resulted in an increase in the fluorescence intensity mainly due to aggregation‐induced emission enhancement (AIEE) properties. The formation of nanoaggregates of R1–R3 were confirmed by scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. The compounds R1–R3 are ideal probes for the fluorescence sensing of bovine serum albumin (BSA) and breast cancer cells by optical cell imaging.