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•A hydrazine-based unsymmetrical bis-Schiff base (L1) was synthesized.•L1 acts as a highly selective and reversible chemosensor for naked-eye detection of Cu2+ ions.•L1 shows ...“turn-off” fluorescence in presence of Cu2+ ions.•L1 coated test strips were capable of rapid detection of Cu2+ ions in aqueous medium.•The Limit of Detection found was below the recommended limit as per WHO guidelines.
A new hydrazine-based unsymmetrical bis-imine-Schiff base 1-(((5-bromothiophen-2-yl)methylene)hydrazono)methyl)naphthalen-2-ol (L1) was synthesized and characterized with FT-IR, 1H NMR, 13C NMR, UV–visible spectroscopy, ESI-MS, and elemental analysis. The solution of L1 in dichloromethane/methanol (9.8:0.2,v/v) mixture shows a rapid change in color from yellow to yellowish brown in the presence of Cu2+ ions. In addition, L1 displays “turn-off” fluorescence preferentially for Cu2+ ions which was attributed to the Chelation Enhanced Quenching (CHEQ) effect caused due to the reversible binding of L1 to paramagnetic Cu2+ in a 2:1 stoichiometric ratio. No interference was caused in the sensing process by other metal ions such as Ag+, Na+, Ni2+, Co2+, Hg2+, Cr3+ Ba2+, Ca2+, Cd2+, Pb2+, Sn2+, Zn2+, Fe3+, Al3+, K+, and Sr2+. The limit of detection was determined to be 2.809 µM. Furthermore, the test strips coated with L1 show a change in color from pale yellow to brownish-yellow in the presence of Cu2+ions in the aqueous medium, and the limit of visual detection was found to be 15 µM, which is well under the maximum recommended limit (31.5 µM) of Cu2+ for drinking water as per WHO guidelines. These observations establish L1 as an efficient reversible chemosensor for sensing Cu2+ in both aqueous and non-aqueous media with high sensitivity and selectivity.
Two palladium(II) Schiff base metal complexes were prepared and characterized by physicochemical and spectroscopic analyses. Moreover, to study the reactivity and bioactivity, the synthesized ...compounds were tested for in-vitro antioxidant, in-vitro anti-inflammatory, in-vitro anti-diabetic, and DNA binding activities. The catalytic activity of Pd(II) metal complexes were evaluated for Suzuki-Miyaura reaction.
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Two palladium (II) Schiff base complexes were prepared by using equivalent molar of Schiff base ligand L1= (E)-2-(((2-(benzylthio)phenyl)imino)methyl)naphthalen-1-ol and L2= (E)-N-(2-(benzylthio)phenyl)-1-phenyl-1-(pyridin-2-yl)methanimine and sodium tetrachloropalladate. The structure of ligands and complexes were characterized by physicochemical and spectroscopic analyses. The results suggested that the Pd(II) complexes have a distorted square planar geometry when coordinated to the tridentate ONS from L1 and the NNS donor ligand from L2. Electronic absorption and spectrofluorometric measurements were employed to investigate the DNA binding of ligands and their associated complexes with CT-DNA. DFT calculations were used to optimize the geometric structures and calculate the electronic and structural properties of the synthesized compounds. NBO analysis was also performed in combination with the TD-DFT method. Moreover, to study the reactivity and bioactivity, the synthesized compounds were tested for in-vitro antioxidant activity by utilizing the DPPH method, in-vitro anti-inflammatory activity using protein denaturation method, and in-vitro anti-diabetic activity employing α-glucosidase and α-amylase enzymes. The results reflect that PdL1 is more biologically potent than PdL2 or other related palladium complexes, as discussed in the literature. The binding mechanism of the synthesized compounds with CT-DNA, α-glucosidase, and α-amylase, was investigated using molecular docking experiments. In addition to these, the catalytic activity of palladium metal complexes (PdL1 and PdL2) was evaluated for the Suzuki-Miyaura reaction for comparisons.
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•Cu(II), Zn(II), and Cd(II) complexes of a new ONO donor Schiff base ligand were synthesized.•Single-Crystal XRD data of ligand L1 showed that ligand is in zwitterionic ...form.•Interaction with calf thymus DNA (CT-DNA) was studied for all the synthesized compounds.•The in-vitro Antibacterial study was performed for all the compounds.•Molecular docking experiment was also carried out.
A series of Cu(II), Zn(II), and Cd(II) complexes coordinated with a new Schiff base ligand (L1) were synthesized. The ligand L1 constituting of ONO donor site was synthesized by the condensation of 5-bromo-3-methoxysalicylaldehyde and 3-aminobenzoic acid and characterized by various analytical and spectroscopic methods. SCXRD data confirmed that the ligand exists as zwitterion possessing E-configuration along the CN bond. The optimization of ligand and complexes were performed using DFT method. The geometry of the Cu(II) complex was acquired to be distorted square planar, whereas Zn(II) and Cd(II) complexes were obtained to be distorted tetrahedral. The DNA binding study was examined for all the synthesized compounds through electronic absorption titration method. The results suggested that ligand exhibited more DNA binding ability which follows the order: CuL1 < ZnL1 < CdL1 < L1. The in-vitro antibacterial study was also performed by employing the micro-broth dilution technique. The result showed that Cd(II) complex depicts better antibacterial properties, in comparison to others. The calculation by TD-DFT was carried out to validate the experimental result of UV–vis spectra with the simulated one. Moreover, molecular docking simulation was also done to confirm the experimental results as well as to better understand the binding mode and nature of compounds with CT-DNA.
Current analysis of circulating tumor cells (CTCs) is hindered by sub-optimal sensitivity and specificity of devices or assays as well as lack of capability of characterization of CTCs with clinical ...biomarkers. Here, we validate a novel technology to enrich and characterize CTCs from blood samples of patients with metastatic breast, prostate and colorectal cancers using a microfluidic chip which is processed by using an automated staining and scanning system from sample preparation to image processing. The Celsee system allowed for the detection of CTCs with apparent high sensitivity and specificity (94% sensitivity and 100% specificity). Moreover, the system facilitated rapid capture of CTCs from blood samples and also allowed for downstream characterization of the captured cells by immunohistochemistry, DNA and mRNA fluorescence in-situ hybridization (FISH). In a subset of patients with prostate cancer we compared the technology with a FDA-approved CTC device, CellSearch and found a higher degree of sensitivity with the Celsee instrument. In conclusion, the integrated Celsee system represents a promising CTC technology for enumeration and molecular characterization.
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•Synthesis and characterization of two Schiff base complexes using microwave-assisted method.•Cu(II)complex showed highest activity in DNA binding/cleavage activity.•Antioxidant ...activities of the complexes indicated that Cu(II) is very good antioxidant.•Cu(II)complex exhibited better cytotoxicity activity.•Zn(II)complex showed good activity as catalyst in MCRs.
Two mononuclear Cu(II) and Zn(II) based complexes were synthesized via microwave-assisted method utilizing Schiff base ligand based on 3,5-di-tertbutylsalicylaldehyde. The compounds were characterized using elemental and spectroscopic analysis methods. The ligand posed as an ON-donor ligand, confirmed by spectrum analysis in the complexes. A geometry optimization analysis was also performed using density functional theory to obtain the geometry, stability, and electronic properties of the synthesized compounds. CuL1 has a distorted square planar geometry, whereas ZnL1 has a distorted tetrahedral geometry. Fluorescence and absorbance spectroscopy were utilized to explore the interaction properties of calf thymus-deoxyribonucleic acid (CT-DNA) with the complexes. The CuL1 and ZnL1 are highly sensitive to DNA binding, with binding constant (Kb) in the range of 105 M−1, representing substantial interaction with CT-DNA, combining intercalation and electrostatic interactions. The Stern-Volmer constant (Ksv) obtained from the fluorescence spectroscopy method varied from 3.31 x 104 to 8.42 x 104 M−1, indicating moderate DNA binding. Circular dichroism spectroscopy confirmed the presence of intercalative binding among the DNA and the complexes. The in-vitro DNA cleavage activity revealed that complexes could efficiently break the supercoiled plasmid DNA without using any external agents. The complex CuL1 induced significant cytotoxicity for Dalton’s lymphoma cancer cell lines, having IC50 values of 18.96 ± 0.021 μM. The antioxidant activity of the compounds was also studied, confirming CuL1 to be the most active antioxidant with IC50 = 399.27 µM. A molecular docking simulation was also conducted to comprehend the compounds' interaction mechanism with CT-DNA (1BNA) and cancer cells (BCL-family proteins). Furthermore, the catalytic activity of the zinc metal complex was assessed for multi-component reactions involving substituted benzaldehydes, malononitrile, and resorcinol.
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•A new Schiff base was synthesized using 4,5-dichloro-o-phenylenediamine and 5-bromosalicylaldehyde.•The ligand was complexed with Cu2+, Ni2+ and Zn2+ to study various biological ...activity.•Zn-complex was more active against Pseudomonas aeruginosa and Streptococcus pneumonia.•Zn-complex showed highest binding activity with CT-DNA.
A new Schiff base ligand named as 2,2'-((1E,1'E)-((4,5-dichloro-1,2-phenylene)bis(azanylylidene))bis(methanylylidene))bis(4-bromophenol) was prepared via condensation reaction between 4,5-dichloro-o-phenylenediamine and 5-bromosalicylaldehyde in 1:2 molar ratio. Various analytical and spectroscopical methods were employed in characterizing the ligand. The coordination behavior and nature of bonding of various metals like Ni(II), Cu(II), and Zn(II) were deduced using 1H-NMR, FT-IR, UV-Visible, EI-MS, and magnetic moment analysis. Job's method was also used to deduce the stoichiometry between ligand and metal ions. Further, the optimization of the structure of compounds was performed computationally, along with their quantum chemical calculations. The Ni(II) and Cu(II) complexes were found to exhibit square planar geometry whereas Zn(II) complex formed distorted planar four coordinated geometry. The synthesized compounds were screened for antibacterial activity against bacteria (two Gram-positive and two Gram-negative). Other bioactivities like DNA binding, antioxidant, and anti-inflammatory activity were also performed. Furthermore, molecular docking analysis to correlate data with experimental data was computed using B-DNA and 6COX enzyme protein receptors.
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•Novel Co(II), Ni(II), and Zn(II) complexes of tridentate ONN ligand are synthesized and utilized as precursors for synthesizing Co3O4, NiO, and ZnO nanoparticles by thermal ...decomposition at 600 °C.•The prepared NPs exhibit semiconducting nature as their calculated energy band gap are 1.67, 3.34, and 3.12 eV for Co3O4, NiO, and ZnO NPs , respectively.•Co3O4, NiO, and ZnO NPs are employed for photocatalytic degradation of MB dye in sunlight.•After 105 min., the maximum percentage of MB dye degradation for Co3O4, NiO, and ZnO was found to be 80 %, 81.2 %, and 86.68 %, respectively.
Three new Co(II), Ni(II), and Zn(II) complexes of tridentate ONN ligand were synthesized from the reaction of 2-amino-3-hydroxypyridine and pyrole-2-carboxyaldehyde and characterized using physio-chemical and analytical methods such as NMR, elemental analyzer, FT-IR, ESI-MS, and magnetic moment measurement. The collected data indicated that prepared complexes have metal:ligand ratio of 1:1 and octahedral geometry for Co(II) and Ni(II) while tetrahedral geometry for Zn(II) complex. The synthesized complexes are utilized as precursors for synthesizing Co3O4, NiO, and ZnO NPs by thermal decomposition at 600 °C, and their structures were defined by PXRD, SEM, UV-DRS, FT-IR, and EDAX. By using Scherrer equation, the average crystallite size calculated for Co3O4, NiO, and ZnO nanoparticles are 22, 18, and 24 nm, respectively. The energy band gap of Co3O4, NiO, and ZnO nanoparticles are 1.67, 3.34, and 3.12 eV, respectively, according to the Tauc baseline calculation, revealing their semiconducting nature. Co3O4, NiO, and ZnO nanoparticles were employed for photocatalytic degradation of methylene blue dye in sunlight. After 105 min., the maximum percentage of MB dye degradation for Co3O4, NiO, and ZnO was found to be 80 %, 81.2 %, and 86.68 %, respectively.
Molecular analysis of circulating tumor cells (CTCs) is hindered by low sensitivity and high level of background leukocytes of currently available CTC enrichment technologies. We have developed a ...novel device to enrich and retrieve CTCs from blood samples by using a microfluidic chip. The Celsee PREP100 device captures CTCs with high sensitivity and allows the captured CTCs to be retrieved for molecular analysis. It uses the microfluidic chip which has approximately 56,320 capture chambers. Based on differences in cell size and deformability, each chamber ensures that small blood escape while larger CTCs of varying sizes are trapped and isolated in the chambers. In this report, we used the Celsee PREP100 to capture cancer cells spiked into normal donor blood samples. We were able to show that the device can capture as low as 10 cells with high reproducibility. The captured CTCs were retrieved from the microfluidic chip. The cell recovery rate of this back-flow procedure is 100% and the level of remaining background leukocytes is very low (about 300-400 cells). RNA from the retrieved cells are extracted and converted to cDNA, and gene expression analysis of selected cancer markers can be carried out by using RT-PCR assays. The sensitive and easy-to-use Celsee PREP100 system represents a promising technology for capturing and molecular characterization of CTCs.
A series of metal complexes of Co (II), Zn (II), and Cu (II) of purine base Schiff base ligand L1 6,6′-((1E,1′E)-((7H-purine-2,6-diyl)bis(azanylylidene))bis (methanylylidene))bis(2-methoxyphenol) and ...L2 3,3′-((1E,1′E)-((7H-purine-2,6-diyl)bis(azanylylidene))bis(methanylylidene))bis(4H-chromen-4-one) were synthesized.
The characterization of the synthesized compounds were investigated through elemental analysis, UV–vis, FT-IR, NMR, and mass spectrometry and optimized by DFT calculations.
CT-DNA binding activity of all the synthesized complexes with the help of UV–visible absorption titration, fluorescence titration, and viscosity measurement were studied.
All the complexes exhibited intercalation mode of binding with CT-DNA.
Molecular docking studies were also performed.
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A series of metal complexes of Co(II), Zn(II), and Cu(II) of purine base Schiff base ligand L1 6,6′-((1E,1′E)-((7H-purine-2,6-diyl)bis(azanylylidene))bis(methanylylidene))bis(2-methoxyphenol) and L2 3,3′-((1E,1′E)-((7H-purine-2,6-diyl)bis(azanylylidene))bis (methanylylidene))bis(4H-chromen-4-one) were synthesized. The characterization of synthesized compounds was investigated through elemental analysis, UV–vis, FT-IR, NMR, and mass spectrometry. The spectroscopic and DFT studies validate the coordination of ligand to the metal centers along with their structural details. In complexes of L1 and L2, the N and O atoms coordinate to metal centers of zinc, cobalt, and copper. However, in the case of L1 complexes the binding mode of oxygen is through phenolic –OH of vanillin moiety. In contrast, complexes of L2 the binding mode of oxygen source is carbonyl oxygen of chromone carboxaldehyde moiety. The stability order follow- ZnL1 < CoL1 < CuL1 < CuL2 < CoL2 < ZnL2. The CT-DNA binding activity of all synthesized complexes with the help of UV–vis absorption titration, fluorescence titration, and viscosity measurement was studied. In both cases, cobalt complexes of L1 and L2 showed high DNA binding activity. The binding constant values are in the order of 105 via intercalation mode of binding. The molecular docking study was performed to speculate on the active binding site between metal complexes and CT-DNA.
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