title: A novel pyrene based fluorescent probe for selective detection of cysteine in presence of other bio-thiols in living cells.
abstract: This manuscript reports the synthesis of pyrene-based fluorescent probe (PA-1) containing α,β-unsaturated carbonyl moiety and its application towards the selective and sensitive detection of cysteine (Cys) over other bio-thiols. The probe, 3-(2-hydroxyphenyl)-1-pyrenyl-2-propenone (PA-1) was synthesized through Claisen-Schmidt condensation between acetyl pyrene and salicylaldehyde. The formed product was characterized by (1)H NMR, (13)C NMR and GC-MS techniques. The probe exhibited absorption maximum at 374nm and emission maximum at 467nm (λex=342nm). The emission intensity of PA-1 was greatly enhanced while adding 2.5nM Cys. This can be attributed to the nucleophilic attack of Cys to the α,β-unsaturated ketone resulting in switching off, intramolecular charge transfer (ICT) from pyrene moiety to the phenolic nucleus. This was confirmed by DFT measurements. The PA-1 exhibited an excellent selectivity towards the determination of 40nM cys in the presence of 250,000-fold higher concentration of common interferents. The emission intensity was linearly increased and the limit of detection was found to be 10pM/L (S/N=3). Interestingly, the response of the PA-1 towards Cys is less than 1min. The confocal laser scanning micrographs of HeLa cells confirmed the cell permeability of the PA-1 and its ability to selectively detect Cys in living cells. In addition, the proposed probe was successfully applied for the determination of Cys in blood serum samples.
authors.affiliation: Centre for Nanoscience and Nanotechnology, Department of Chemistry, Gandhigram Rural Institute, Gandhigram, 624302 Dindigul, Tamil Nadu, India.
authors.forename: B Kirthika
authors.initials: BK
authors.lastname: Rani
authors.affiliation: Centre for Nanoscience and Nanotechnology, Department of Chemistry, Gandhigram Rural Institute, Gandhigram, 624302 Dindigul, Tamil Nadu, India. Electronic address: sabrahamjohn@ruraluniv.ac.in.
authors.forename: S Abraham
authors.initials: SA
authors.lastname: John
mesh_terms: D015374:Biosensing Techniques / Q000379:methods; D003545:Cysteine / Q000032:analysis* / Q000097:blood; D005456:Fluorescent Dyes / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D057230:Limit of Detection; D018613:Microscopy, Confocal / Q000379:methods; D011721:Pyrenes / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods; D013438:Sulfhydryl Compounds / Q000032:analysis
chemical_list: D005456:Fluorescent Dyes; D011721:Pyrenes; D013438:Sulfhydryl Compounds; C030984:pyrene; D003545:Cysteine
keywords: Confocal microscopy; Cysteine; HeLa cells; Intramolecular charge transfer; Pyrene based fluorescent probe; Spectrofluorimetry