A Nitronaphthalimide Probe for Fluorescence Imaging of Hypoxia in Cancer Cells

The bioreductive enzymes typically upregulated in hypoxic tumor cells can be targeted for developing diagnostic and drug delivery applications. In this study, a new fluorescent probe 4?(6?nitro?1,3?dioxo?1H?benzo[de]isoquinolin?2(3H)?yl)benzaldehyde (NIB) based on a nitronaphthalimide skeleton that could respond to nitroreductase (NTR) overexpressed in hypoxic tumors is designed and its application in imaging tumor hypoxia is demonstrated. The docking studies revealed favourable interactions of NIB with the binding pocket of NTR-Escherichia coli. NIB, which is synthesized through a simple and single step imidation of 4?nitro?1,8?naphthalic anhydride displayed excellent reducible capacity under hypoxic conditions as evidenced from cyclic voltammetry investigations. The fluorescence measurements confirmed the formation of identical products (NIB-red) during chemical as well as NTR?aided enzymatic reduction in the presence of NADH. The potential fluorescence imaging of hypoxia based on NTR-mediated reduction of NIB is confirmed using in-vitro cell culture experiments using human breast cancer (MCF?7) cells, which displayed a significant change in the fluorescence colour and intensity at low NIB concentration within a short incubation period in hypoxic conditions.

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Synthesis and fabrication of highly functionalized Jeffamine antimicrobial polymeric coating

A simple, robust, and eco‐friendly technique for the fabrication of functionalized Jeffamine polymer in an aqueous medium is developed. The polymer is prepared by post polymerization modification of Jeffamine ED‐2003 of molecular weight 2000. The structure of the modified polymer was studied in detail using FTIR and NMR (¹H and ¹³C NMR) spectroscopic methods. The thermal properties and degradation of the polymer were examined by DSC and TGA techniques. The polymer exhibited glass transition temperature (T_g) at 115°C. The functionalized polymeric compound showed good antimicrobial activity against gram‐negative bacterium Escherichia coli, a tubercular variant Mycobacterium smegmatis, and gram‐positive bacterium Staphylococcus aureus with a zone of inhibition of 6 to 12, 9, and 5 to 9 mm diameter, respectively. The compound also showed good activity against the fungus, Candida albicans, with a zone of inhibition of 6 to 11 mm diameter. The morphology of the polymer films and interaction of the microbes with functionalized Jeffamine polymer were investigated by using scanning electron microscopy (SEM).