Banashree Bondhopadhyay

Highly selective turn-on fluorescent sensor for nanomolar detection of biologically important Zn2+ based on isonicotinohydrazide derivative: application in cellular imaging.

A new Zn(2+) selective chemosensor (3) was synthesized by condensation of commercially available substituted salicylaldehyde and isonicotinohydrazide, and characterized by single crystal X-ray crystallography. Receptor 3 with Zn(2+) exhibited a highly selective and pronounced enhancement in the fluorescence emission among different cations by forming a 2:1 complex. The receptor can detect Zn(2+) up to nanomolar level (6.75 nM) with good tolerance of other metal ions and can be used for in vitro cellular imaging.

“Turn-on” fluorescent dipodal chemosensor for nano-molar detection of Zn2+: Application in living cells imaging

A malonohydrazide derivative bearing an imine and phenolic group was synthesized and had a high affinity and selectivity towards Zn(2+). The recognition properties of receptor 1 were evaluated using absorbance and fluorescence spectroscopy. The 1:1 stoichiometry of 1.Zn(2+) was confirmed from jobs plot, mass spectra and density functional theory (DFT). The detection of Zn(2+) in intracellular environment of HeLa cell through confocal microscopy was successfully applied for live cell imaging.

A highly selective fluorescent ‘turn-on’ chemosensor for Hg2+ based on a phthalazin-hydrazone derivative and its application in human cervical cancer cell imaging

A new phthalazin-hydrazone based fluorescent chemosensor (E)-5-(diethylamino)-2-((2-(phthalazin-1-yl)hydrazono)methyl)phenol (1) was reported. Sensor 1 showed a high selectivity and sensitivity towards Hg2+ by giving significant fluorescence enhancement at 550 nm over other tested cations in DMSO/H2O (80 : 20, v/v) medium. The association constant was 1.0 × 104 M−1 between sensor 1 and Hg2+. Sensor 1 showed a nanomolar detection limit of 26.1 nM Hg2+. Finally, the fluorescence imaging experiments for the detection of intracellular Hg2+ in human cervical cancer HeLa cells showed its practical utility in biological samples.

Simultaneous knockdown of uPA and MMP9 can reduce breast cancer progression by increasing cell-cell adhesion and modulating EMT genes

In cancer progression, proteolytic enzymes like serine proteases and metalloproteinases degrade the basement membrane enabling the tumor cells to invade the adjacent tissues. Thus, invasion and metastasis are augmented by these enzymes. Simultaneous silencing of uPA and MMP9 in breast cancer cells decreased the wound healing, migratory, invasive and adhesive capacity of the cells. After simultaneous down regulation, cells were seen to be arrested in the cell cycle. There was a remarkable increase in the expression of cell to cell adhesion molecule E–cadherin, and decrease in Vimentin and Snail expression. In addition, there was a significant decrease in the expression of the stem cell marker Oct-4. In the breast tumor samples it has been observed that, tumors, expressing higher level of uPA and MMP9, express less amount of E–cadherin. It has also been observed that few tumors also show, Vimentin positive in the ductal epithelial area. Thus, our model can help for checking the aggressive tumor invasion by blocking of uPA and MMP9. Our present observations also give the concept of the presence of aggressive epithelial cells with mesenchymal nature in the tumor micro-environment, altering the expression of EMT genes.

Pyrrole‐coupled salicylimine‐based fluorescence “turn on” probe for highly selective recognition of Zn2+ ions in mixed aqueous media: Application in living cell imaging

Cation sensing behaviour of a pyrrole‐based derivative (2‐hydroxyl 3 methyl 6 isopropyl benzaldehyde}‐3,4‐dimethyl‐1H‐pyrrole‐2‐carbohydrazide (receptor 3) has been explored and is found to be selective towards Zn2+ over a variety of tested cations. The receptor 3 has shown high selectivity and sensitivity towards Zn2+ over the other alkali, alkaline earth and transition metal ions. In the presence of Zn2+, absorption band of receptor 3 has shown the red shift. The sensing behaviour has been suggested to continue via enhancement process which has further been supported by UV‐vis absorption and theoretical density functional theory (DFT) calculations indicating the formation of a 1:1 complex between the pyrrole based receptor 3 and Zn2+. The present work is presenting a highly selective dual channel colorimetric sensor for zinc with great sensitivity. The developed sensor was successfully applied to image intracellular Zn2+ in living cells. Copyright