ABSTRACT
Polyvinyl-pyrrolidone capped spherical cadmium sulphide quantum dots (CdS-PVP QDs), 2-6 nm in size, were developed as a selective turn-on fluorescence nanosensor for monohydrogen phosphate ion (HPO42-) in aqueous medium. Fluorescence intensity of CdS-PVP QDs significantly increased with addition of HPO42- ions, whereas the other common inorganic ions had very little effect on the fluorescence intensity. The proposed sensor may be efficiently used for the detection of HPO42- ions at a low level of concentration up to 213 nM in real urine sample. Cell imaging study indicates that the CdS-PVP QDs are cell permeable and can detect the intracellular distribution of HPO42- ions under fluorescence microscope. The CdS-PVP QDs showed considerable activity against Staphylococcus aureus also.
Subject(s)
Anti-Infective Agents/pharmacology , Cadmium Compounds/chemistry , Cadmium Compounds/pharmacology , Phosphates/analysis , Povidone/chemistry , Quantum Dots/chemistry , Sulfides/chemistry , Sulfides/pharmacology , Density Functional Theory , Fluorescence , Humans , Hydrogen-Ion Concentration , Ions , Limit of Detection , Microbial Sensitivity Tests , Nanoparticles/chemistry , Nanoparticles/ultrastructure , Particle Size , Powders , Salinity , Spectroscopy, Fourier Transform Infrared , Temperature , X-Ray DiffractionABSTRACT
Two new ruthenium(II) complexes of Schiff base ligands (L) derived from cinnamaldehyde and ethylenediamine formulated as [Ru(L)(bpy)2](ClO4)2, where L1 = N,N'-bis(4-nitrocinnamald-ehyde)ethylenediamine and L2 = N,N'-bis(2-nitrocinnamaldehyde)-ethylenediamine for complex 1 and 2, respectively, were isolated in pure form. The complexes were characterized by physicochemical and spectroscopic methods. The electrochemical behavior of the complexes showed the Ru(III)/Ru(II) couple at different potentials with quasi-reversible voltammograms. The interaction of the complexes with calf thymus DNA (CT-DNA) using absorption, emission spectral studies and electrochemical techniques have been used to determine the binding constant, Kb and the linear Stern-Volmer quenching constant, KSV. The results indicate that the ruthenium(II) complexes interact with CT-DNA strongly in a groove binding mode. The interactions of bovine serum albumin (BSA) with the complexes were also investigated with the help of absorption and fluorescence spectroscopy tools. Absorption spectroscopy proved the formation of a ground state BSA-[Ru(L)(bpy)2](ClO4)2 complex. The antibacterial study showed that the Ru(II) complexes (1 and 2) have better activity than the standard antibiotics but weak activity than the ligands.
Subject(s)
Anti-Bacterial Agents/metabolism , Anti-Bacterial Agents/pharmacology , DNA/metabolism , Organometallic Compounds/metabolism , Organometallic Compounds/pharmacology , Ruthenium/chemistry , Serum Albumin, Bovine/metabolism , Animals , Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/chemistry , Cattle , Chemistry Techniques, Synthetic , Ligands , Models, Molecular , Molecular Conformation , Organometallic Compounds/chemical synthesis , Organometallic Compounds/chemistry , Protein Binding , Quantum Theory , Schiff Bases/chemistryABSTRACT
A structurally modified quinazoline derivative (L) acts as highly selective chemosensor for Al(3+) ions in DMSO-H2O (1:9, v/v) over the other competitive metal ions. L shows a red shifted fluorescence after the addition of Al(3+) ions and later the further fluorescence enhancement is due to chelation enhanced fluorescence (CHEF) through inhibition of photoinduced electron transfer (PET). This probe (L) detects Al(3+) ions as low as 9nM in DMSO-H2O (1:9, v/v) at biological pH. The non-cytotoxic probe (L) can efficiently detect the intercellular distribution of Al(3+) ions in living cells under a fluorescence microscope to exhibit its sensible applications in the biological systems.
Subject(s)
Aluminum/analysis , Chelating Agents/chemistry , Fluorescent Dyes/chemistry , Quinazolines/chemistry , Cations/analysis , Cell Line , Dimethyl Sulfoxide/chemistry , Electron Transport , Humans , Microscopy, Fluorescence , Permeability , Photochemical Processes , Spectrometry, Fluorescence , Water/chemistryABSTRACT
A newly designed fluorescent aluminum(III) complex (L'-Al; 2) of a structurally characterized non-fluorescent rhodamine Schiff base (L) has been isolated in pure form and characterized using spectroscopic and physico-chemical methods with theoretical density functional theory (DFT) support. On addition of Al(III) ions to a solution of L in HEPES buffer (1 mM, pH 7.4; EtOH-water, 1 : 3 v/v) at 25 °C, the systematic increase in chelation-enhanced fluorescence (CHEF) enables the detection of Al(III) ions as low as 60 nM with high selectivity, unaffected by the presence of competitive ions. Interestingly, the Al(III) complex (L'-Al; 2) is specifically able to detect fluoride ions by quenching the fluorescence in the presence of large amounts of other anions in the HEPES buffer (1 mM, pH 7.4) at 25 °C. On the basis of our experimental and theoretical findings, the addition of Al(3+) ions to a solution of L helps to generate a new fluorescence peak at 590 nm, due to the selective binding of Al(3+) ions with L in a 1 : 1 ratio with a binding constant (K) of 8.13 × 10(4) M(-1). The Schiff base L shows no cytotoxic effect, and it can therefore be employed for determining the intracellular concentration of Al(3+) and F(-) ions by 2 in living cells using fluorescence microscopy.
Subject(s)
Aluminum/chemistry , Coordination Complexes/chemistry , Fluorescent Dyes/chemistry , Fluorides/chemistry , Rhodamines/chemistry , Coordination Complexes/chemical synthesis , Coordination Complexes/metabolism , Fluorescent Dyes/chemical synthesis , Fluorescent Dyes/metabolism , HeLa Cells , Humans , Inhibitory Concentration 50 , Ions , Models, Molecular , Schiff Bases/chemistry , Staining and LabelingABSTRACT
A coumarin-based fluorogenic probe, PCO-1, senses carbon monoxide (CO) selectively in HEPES buffer at pH 8.0 through the intramolecular cyclization-elimination pathway based on Pd(0) mediated reaction. The probe exhibits a 'turn-on' response of CO over a variety of relevant reactive oxygen, nitrogen and sulfur species.
Subject(s)
Carbon Monoxide/analysis , Fluorescent Dyes/chemistry , Lead/chemistry , Spectrometry, Fluorescence , Cell Line, Tumor , Coumarins/chemistry , Cyclization , Humans , Microscopy, Fluorescence , Reactive Nitrogen Species/chemistry , Reactive Oxygen Species/chemistry , Sulfur Compounds/chemistry , Water/chemistryABSTRACT
Copper(II) and copper(I) complexes of a newly designed and crystallographically characterized Schiff base (HL) derived from rhodamine hydrazide and cinnamaldehyde were isolated in pure form formulated as [Cu(L)(NO3)] (L-Cu) (1) and [Cu(HL)(CH3CN)(H2O)]ClO4 (HL-Cu) (2), and characterized by physicochemical and spectroscopic tools. Interestingly, complex 1 but not 2 offers red fluorescence in solution state, and eventually HL behaves as a Cu(II) ions selective FRET based fluorosensor in HEPES buffer (1 mM, acetonitrile-water: 1/5, v/v) at 25 °C at biological pH with almost no interference of other competitive ions. The dependency of the FRET process on the +2 oxidation state of copper has been nicely supported by exhaustive experimental studies comprising electronic, fluorimetric, NMR titration, and theoretical calculations. The sensing ability of HL has been evaluated by the LOD value towards Cu(II) ions (83.7 nM) and short responsive time (5-10 s). Even the discrimination of copper(I) and copper(II) has also been done using only UV-Vis spectroscopic study. The efficacy of this bio-friendly probe has been determined by employing HL to detect the intercellular distribution of Cu(II) ions in HeLa cells by developing image under fluorescence microscope.
Subject(s)
Coordination Complexes , Copper , Schiff Bases , Acrolein/analogs & derivatives , Acrolein/chemistry , Cell Survival/drug effects , Coordination Complexes/chemical synthesis , Coordination Complexes/chemistry , Coordination Complexes/pharmacology , Copper/chemistry , Copper/pharmacology , Fluorescence Resonance Energy Transfer , HeLa Cells , Humans , Hydrazines/chemistry , Microscopy, Fluorescence , Oxidation-Reduction , Rhodamines/chemistry , Schiff Bases/chemical synthesis , Schiff Bases/chemistry , Schiff Bases/pharmacologyABSTRACT
A newly designed and structurally characterized cell permeable diformyl-p-cresol based receptor (HL) selectively senses the AsO3(3-) ion up to ca. 4.1 ppb in aqueous media over the other competitive ions at biological pH through an intermolecular H-bonding induced CHEF (chelation-enhanced fluorescence) process, established by detailed experimental and theoretical studies. This biofriendly probe is highly competent in recognizing the existence of AsO3(3-) ions in a living organism by developing an image under a fluorescence microscope and useful to estimate the amount of arsenite ions in various water samples.
Subject(s)
Arsenites/analysis , Chelating Agents/chemistry , Cresols/chemistry , Fluorescent Dyes/chemistry , Water/chemistry , Chelating Agents/chemical synthesis , Cresols/chemical synthesis , Fluorescent Dyes/chemical synthesis , HeLa Cells , Humans , Hydrogen Bonding , Hydrogen-Ion Concentration , Ions/analysis , Microscopy, Fluorescence , Molecular Structure , Quantum TheoryABSTRACT
A newly synthesized and crystalographically characterized napthelenepyrazol conjugate, 1-[(5-phenyl-1H-pyrazole-3-ylimino)-methyl]-naphthalen-2-ol (HL) behaves as an Al(III) ion-selective chemosensor through internal charge transfer (ICT)-chelation-enhanced fluorescence (CHEF) processes in 100 mM HEPES buffer (waterDMSO 5:1, v/v) at biological pH with almost no interference of other competitive ions. This mechanism is readily studied from electronic, fluorimetric and (1)H NMR titration. The probe (HL) behaved as a highly selective fluorescent sensor for Al(III) ions as low as 31.78 nM within a very short response time (1520 s). The sensor (HL), which has no cytotoxicity, is also efficient in detecting the distribution of Al(III) ions in HeLa cells via image development under fluorescence microscope.
Subject(s)
Aluminum/chemistry , Biomarkers/analysis , Coordination Complexes/chemistry , Naphthols/chemistry , Pyrazoles/chemistry , Spectrometry, Fluorescence , Chelating Agents/chemistry , Chemistry Techniques, Analytical , Coordination Complexes/chemical synthesis , Coordination Complexes/metabolism , Crystallography, X-Ray , Fluorescent Dyes/chemical synthesis , Fluorescent Dyes/chemistry , HeLa Cells , Humans , Ions/chemistry , Microscopy, Confocal , Molecular Conformation , Naphthols/chemical synthesis , Pyrazoles/chemical synthesis , Water/chemistryABSTRACT
The effect of substituents on FRET in two newly designed rhodamine-based Hg(2+) ion selective chemosensors (L¹ and L²) has been explored by a systematic experimental and theoretical study. Comparison of these sensors in the analytical study and imaging of Hg(2+) ions in living cells has also been included.
