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A new coumarin based fluorescent switch PCEH is fabricated which displays high selective sensing towards Al3+ among other metal cations at physiological pH. On gradual addition of Al3+, PCEH shows a brilliant "turn-on" emission enhancement in MeOH/H2O (4/1, v/v) solution. This new fluorescent switch is proven to be a reversible probe by gradual addition of F− into the PCEH-Al3+ solution. Detection limit as well as binding constant values are calculated to be in the order of 10–9 M and 104 M−1 respectively. We have also explored its potential as a biomarker in the application of live cell imaging using breast cancer cells (MDA-MB-231 cell). [ABSTRACT FROM AUTHOR]

Vasculogenic mimicry (VM), defined as an endothelial cell independent alternative mechanism of blood and nutrient supply by dysregulated tumor cells, is associated with poor prognosis in oral squamous cell carcinoma (OSCC). Here we aim to investigate the underlying molecular mechanism of the synergistic effect of phytochemical Lupeol and standard microtubule inhibitor Paclitaxel in reversing the hypoxia induced VM formation in OSCC. The results demonstrated that the hypoxia induced upregulation of HIF-1α led to augmentation of signaling cascade associated with extracellular matrix remodeling and EMT phenotypes that are mechanistically linked to VM. Induction of HIF-1α altered the expression of EMT/CSC markers (E-Cadherin, Vimentin, Snail, Twist and CD133) and enhanced the ability of cell migration/invasion and spheroid formation. Subsequently, the targeted knockdown of HIF-1α by siRNA led to the perturbation of matrigel mediated tube formation as well as of Laminin-5γ2 expression with the down-regulation of VE-Cadherin, total and phosphorylated (S-897) EphA2, pERK1/2 and MMP2. We also observed that Lupeol in association with Paclitaxel resulted to apoptosis and the disruption of VM associated phenotypes in vitro. We further validated the impact of this novel interventional approach in a patient derived tumor explant culture model of oral malignancy. The ex vivo tumor model mimicked the in vitro anti-VM potential of Lupeol-Paclitaxel combination through down-regulating HIF-1α/EphA2/Laminin-5γ2 cascade. Together, our findings elucidated mechanistic underpinning of hypoxia induced Laminin-5γ2 driven VM formation highlighting that Lupeol-Paclitaxel combination may serve as novel therapeutic intervention in perturbation of VM in human OSCC. [ABSTRACT FROM AUTHOR]

A highly sensitive, reversible, reusable and fluorogenic "turn-on" probe (HBTC) is fabricated for the sole detection of Al3+. On incremental addition of Al3+ in a solution of HBTC in ACN : H2O (4 : 1), a sharp "turn-on" emission enhancement is observed at 480 nm. The reversibility of the probe (HBTC) was displayed on the addition of F− solution. The detection limit is found to be of the order of 10−9 M which suggests that HBTC can detect Al3+ at a very minute level. The mechanism for Al3+ detection in ACN : H2O (4 : 1) is attributed to forbidding C＝N isomerization and ESIPT process simultaneously turning on the chelation-enhanced fluorescence process. The reusability and real-time application of the probe are also studied. Bioimaging study reveals that HBTC can detect Al3+ in human breast cancer cells (MDA-MB-231). Electronic structure of the probe is explained by density functional theory. [ABSTRACT FROM AUTHOR]

A phenylazo appended ortho‐vanillin Schiff base scaffold (HAZ) has been used for selective colorimetric sensing of Cu2+ in semi‐aqueous medium (methanol–water, 1:1, v/v) in the presence of 16 cations and 20 anions, and the limit of detection is 1.8 × 10−7 M. The structures of HAZ and Cu (II) complex, [Cu(AZ)2], have been characterised by spectroscopic data (UV–Vis, Fourier transform infrared and electron paramagnetic resonance) and established by the single crystal X‐ray diffraction measurement. The Job's plot from the absorption studies has also confirmed the 1:2 stoichiometry of Cu2+:HAZ. The absorption spectrum of [Cu (AZ)2] has returned to the spectrum of HAZ on the addition of Na2EDTA solution which is again recovered upon the addition of Cu2+ solution. Discrete Fourier transform computations were carried out using the coordinates of the X‐ray structures of the compounds, and the molecular functions were used to correlate the solution spectroscopic properties. In addition to this, the probe is treated on MDA‐MB 231 breast cancer cells to check the cytotoxicity. The probe is used for the detection of trace quantity of Cu2+ in the cancer cell. [ABSTRACT FROM AUTHOR]

A diversified biphenyl thiosemicarbazide based chemosensor (HBMC) has been fabricated and reported for the specific detection of Cd 2+ in a MeOH : H 2 O (4 : 1) solution. We observed a chromogenic change from colorless to light yellow colour, and it showed a "turn-on" fluorogenic change from non fluorescent to blooming cyan colour. In fluorometric titration a sharp "turn-on" emission for Cd 2+ was observed with a ∼16 fold increase in fluorescence intensity value at 496 nm by incremental addition of Cd 2+ ions in the MeOH : H 2 O (4 : 1) solution. The reversibility of the chemosensor (HBMC) was confirmed by a sequential addition of the EDTA solution. Again the binding stoichiometry of HBMC with Cd 2+ was found to be 2 : 1, as confirmed by Job's plot analysis and HRMS spectra of the HBMC-Cd 2+ complex. The mechanism for Cd 2+ sensing in MeOH : H 2 O (4 : 1) is based upon the inhibition of CN isomerization and ESIPT process and simultaneously turning on the CHEF (chelation enhanced fluorescence) process. The limit of detection for Cd 2+ was found to be in the order of 10 -8 (M), which implies that HBMC is an efficient probe to detect Cd 2+ at the microscopic level. A reusability study was performed and on-sight detection of cadmium ions by the chemosensor (HBMC) was established by dip-stick experiment. In vitro detection of Cd 2+ in human breast cancer cells (MDA-MB-231) by HBMC discloses its cell permeability and biocompatible nature. Computational studies (DFT and TDDFT) with the probe HBMC and HBMC-Cd 2+ complex were also performed.