Dipranjan Laha

A novel study of antibacterial activity of copper iodide nanoparticle mediated by DNA and membrane damage.

In this article potential activity of nanoparticles (NPs) of copper iodide (CuI) as an antibacterial agent has been presented. The nano particles are synthesized by co-precipitation method with an average size of 8 nm as determined by Transmission Electron Microscope (TEM). The average charge of the NPs is -21.5 mV at pH 7 as obtained by zeta potential measurement and purity is determined by XRD. These NPs are able to kill both gram positive and gram negative bacteria. Among the bacteria tested, DH5α is more sensitive but Bacillus subtilis is more resistant to NPs of CuI. Consequently, the MIC and MBC values of DH5α is least (0.066 mg/ml and 0.083 mg/ml respectively) and B. subtilis is highest (0.15 mg/ml and 0.18 mg/ml respectively) among the tested bacterial strains. From our studies it is inferred that CuI NPs produce reactive oxygen species (ROS) in both gram negative and gram positive bacteria and it also causes ROS mediated DNA damage for the suppression of transcription as revealed by reporter gene assay. Probably ROS is formed on the surface of NPs of CuI in presence of amine functional groups of various biological molecules. Furthermore they induce membrane damage as determined by atomic force microscopy (AFM). Thus production of ROS and membrane damage are major mechanisms of the bactericidal activity of these NPs of CuI.

Interplay between autophagy and apoptosis mediated by copper oxide nanoparticles in human breast cancer cells MCF7.

BACKGROUND Metal oxide nanoparticles are well known to generate oxidative stress and deregulate normal cellular activities. Among these, transition metals copper oxide nanoparticles (CuO NPs) are more compelling than others and able to modulate different cellular responses. METHODS In this work, we have synthesized and characterized CuO NPs by various biophysical methods. These CuO NPs (~30nm) induce autophagy in human breast cancer cell line, MCF7 in a time- and dose-dependent manner. Cellular autophagy was tested by MDC staining, induction of green fluorescent protein-light chain 3 (GFP-LC3B) foci by confocal microscopy, transfection of pBABE-puro mCherry-EGFP-LC3B plasmid and Western blotting of autophagy marker proteins LC3B, beclin1 and ATG5. Further, inhibition of autophagy by 3-MA decreased LD50 doses of CuO NPs. Such cell death was associated with the induction of apoptosis as revealed by FACS analysis, cleavage of PARP, de-phosphorylation of Bad and increased cleavage product of caspase 3. siRNA mediated inhibition of autophagy related gene beclin1 also demonstrated similar results. Finally induction of apoptosis by 3-MA in CuO NP treated cells was observed by TEM. RESULTS This study indicates that CuO NPs are a potent inducer of autophagy which may be a cellular defense against the CuO NP mediated toxicity and inhibition of autophagy switches the cellular response into apoptosis. CONCLUSIONS A combination of CuO NPs with the autophagy inhibitor is essential to induce apoptosis in breast cancer cells. GENERAL SIGNIFICANCE CuO NP induced autophagy is a survival strategy of MCF7 cells and inhibition of autophagy renders cellular fate to apoptosis.

Synthesis of highly fluorescent nitrogen and phosphorus doped carbon dots for the detection of Fe3+ ions in cancer cells

Highly fluorescent nitrogen and phosphorus-doped carbon dots with a quantum yield 59% have been successfully synthesized from citric acid and di-ammonium hydrogen phosphate by single step hydrothermal method. The synthesized carbon dots have high solubility as well as stability in aqueous medium. The as-obtained carbon dots are well monodispersed with particle sizes 1.5-4 nm. Owing to a good tunable fluorescence property and biocompatibility, the carbon dots were applied for intercellular sensing of Fe(3+) ions as well as cancer cell imaging.

One-pot synthesis of carbon dot-entrenched chitosan-modified magnetic nanoparticles for fluorescence-based Cu2+ ion sensing and cell imaging

In this work, a new synthetic approach is developed for the synthesis of fluorescent magnetic nanoparticles which are explored for the detection of mostly abundant transition metal Cu2+ ions and cell imaging. These fluorescent magnetic nanoparticles are synthesized by decoration of carbon dots (CDs) on carboxymethyl chitosan-wrapped Fe3O4 nanoparticles (NPs) in a one-pot method. The fluorescent magnetic nanoparticles are characterized by Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), a vibrating sample magnetometer (VSM), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), dynamic light scattering (DLS) and photoluminescence study. Importantly, the fluorescent magnetic nanoparticles exhibit excellent selectivity for the determination of Cu2+ ions over other metal ions. The fluorescence intensity was found to be successfully quenched by adding different concentrations of Cu2+ ions. Here, the reduction of fluorescence intensity proves the detection of Cu2+ ions in a linear range of 0.01–200 µM, with a detection limit of 0.56 µM at a signal-to-noise ratio of 3. The fluorescent magnetic nanoparticles were successfully applied to cell imaging and subsequently conjugated with folic acid for cancer cell imaging, which suggests that the synthesized nanoparticles have great potential for diagnostic purposes.

One-pot synthesis of folic acid encapsulated upconversion nanoscale metal organic frameworks for targeting, imaging and pH responsive drug release

In this work, a new theranostic nanoplatform is developed to construct an anticancer drug carrier by integrating the distinct advantages of upconversion nanoparticles (UCNPs) and metal organic frameworks (MOFs) encapsulated with a targeting ligand. Here NaYF4:Yb3+,Er3+ is chosen as an upconversion nanoparticle for its high luminescence properties. Then, folic acid encapsulated Zeolitic Imidazolate Framework-8 (ZIF-8) is directly coated on UCNPs in one step to form a monodispersed core-shell structured nanocomposite (labeled as UCNPs@ZIF-8/FA). The synthesized upconversion nanoscale MOFs (NMOFs) are simultaneously used as a targeted anticancer drug carrier and in cellular imaging. The UCNP@ZIF-8/FA nanocomposites are found to be nontoxic towards the human cervix adenocarcinoma (HeLa) and mouse fibroblast (L929) cell lines via a cell viability assay. It is worthwhile noting that, the anticancer drug 5-fluorouracil (5-FU) is absorbed into UCNP@ZIF-8/FA nanocomposites (loading amount 685 mg g-1) and also pH responsive drug release is observed. The as-prepared 5-FU loaded UCNP@ZIF-8/FA nanocomposites exhibited greater cytotoxicity towards HeLa cells due to the folate receptor-mediated endocytosis. Our study highlights the potential of developing multifunctional upconversion NMOFs for simultaneous targeted cellular imaging with delivery of anticancer drugs.

A novel drug “copper acetylacetonate” loaded in folic acid-tagged chitosan nanoparticle for efficient cancer cell targeting

Abstract Several copper compounds have proven anti-cancer activity. Similarly, curcumin a derivative of 1,3 diketone, which is not plenty in nature, has comparable anti-cancer activity. In this work, we have explored the synergistic anti-cancer activity of copper ion and acetylacetone complex containing 1,3 diketone group. The cytotoxicity of the copper acetylacetonate (CuAA) complex was evaluated on various cancer cells and LD50 doses were determined. To investigate the mechanism, various biochemical assays were performed and reactive oxygen species as well as the glutathione level in the cell were found to be increased after the treatment with the above-mentioned complex. Further this reagent induced apoptosis and reduced mitochondrial membrane potential of the cells. Because of the poor solubility and reasonable cytotoxicity of CuAA, polymer nanoparticles (NPs) of chitosan derivatives were used for delivery in cancer cells. For the targeted delivery, folic acid-tagged hydrophobic-modified chitosan NPs were developed and the CuAA was encapsulated. Finally, these drug-encapsulated NPs were successfully delivered to folate receptor over-expressed cancer cells. Thus using nanotechnology, we developed an anti-cancer agent suitable for targeted delivery.

Evaluation of copper iodide and copper phosphate nanoparticles for their potential cytotoxic effect

To explore the potential biological activities of transition metal-based nanoparticles (NPs), we synthesized two copper-based NPs, CuI and Cu3(PO4)2. The structural features of these NPs were determined by the X-ray diffraction (XRD), dynamic light scattering (DLS) and transmission electron microscopy (TEM). The size of CuI and Cu3(PO4)2 NPs were 35 ± 4.2 nm and 67 ± 6.3 nm respectively as determined by TEM. Cell viability, generation of reactive oxygen species (ROS), cell cycle and induction of apoptosis were assessed on human breast cancer cell line MCF7 after the treatment of these NPs. Exposure of CuI and Cu3(PO4)2 NPs decreased cell viability in a dose-dependent manner. Also, CuI NPs produced more ROS compared to Cu3(PO4)2 and presence of N-acetyl cysteine (NAC) along with NPs increased the cell survival. Cell cycle analysis indicated that after exposure of these NPs at their respective LD50 doses increased Sub G1 and G2/M peak after 8 h and 24 h of treatment respectively. Apoptosis study by AnnexinV-FITC staining showed slight increased in the early and late apoptosis after 8 h of treatment and most of the cells were dead after 24 h of treatment. Thus our observations suggest that the exposure of these two NPs induced dose-dependent cytotoxicity on MCF7 cell that is associated with ROS-mediated apoptosis.

Folic acid modified copper oxide nanoparticles for targeted delivery in in vitro and in vivo systems

Copper oxide nanoparticles are known to exhibit toxic effects on a variety of cell types. In the present study, copper oxide nanoparticles were modified with folic acid for targeted delivery. The physicochemical properties of copper oxide nanoparticles (CuO NPs) and folic acid conjugated copper oxide nanoparticles (CuO–FA NPs) were studied by Dynamic light scattering (DLS), Field emission scanning electron microscopy (FE-SEM) and Fourier transform infrared spectroscopy (FTIR). To determine targeting efficacy, we have used folate receptor positive and folate receptor knock down human breast cancer cells MCF7. Flow cytometric analysis, generation of ROS and expression of apoptotic proteins (cleaved PARP, decreased p-BAD) indicated that most cell death occurred through apoptosis in CuO–FA NPs treated MCF7 cells. In the in vivo study, we used Daltons lymphoma (DL) cell induced tumor in mice. We successfully delivered CuO and CuO–FA NPs through peritoneal injection after induction of the tumor. Reactive oxygen species (ROS), glutathione (GSH) was measured in DL cells isolated from tumor bearing mice. All of these data indicated that CuO–FA NPs was more effective in killing the tumor cells and successful reduction of the tumor was observed in CuO–FA NPs treated mice after 15 days of treatment. These findings have important implications for understanding the potential anticancer properties induced by folic acid modified CuO NPs.

One pot synthesis of carbon dots decorated carboxymethyl cellulose-hydroxyapatite nanocomposite for drug delivery, tissue engineering and Fe3+ ion sensing

In this work, carbon dots conjugated carboxymethyl cellulose-hydroxyapatite nanocomposite has been synthesized by one-pot synthesis method and used for multiple applications like metal ion sensing, osteogenic activity, bio-imaging and drug carrier. The structure and morphology of the nanocomposite were systematically characterized by FTIR, XRD, TGA, FESEM, TEM and DLS. Results clearly demonstrated the formation of fluorescent enabled carbon dots conjugated nanocomposite from carboxymethyl cellulose-hydroxyapatite nanocomposite by a simple thermal treatment. The synthesized nanocomposite is smaller than 100 nm and exhibits fluorescence emission band around 440 nm upon excitation with 340 nm wavelength. In the meantime, the nanocomposite was loaded with a chemotherapeutic drug, doxorubicin to evaluate the drug loading potential of synthesized nanocomposite. Moreover, the as-synthesized nanocomposite showed good osteogenic properties for bone tissue engineering and also exhibited excellent selectivity and sensitivity towards Fe3+ ions.

Targeted delivery of “copper carbonate” nanoparticles to cancer cells in vivo

Various metal based nanoparticles such as Zn, Co and Cu are well known to have an anticancer effect. In targeting these nanoparticles, it is a great challenge to minimize the toxicity to normal cells. Folate receptors are expressed in a variety of cancer cells. Folic acid mediated targeting is a well accepted technique for cancer therapeutics. The purpose of this study is to explore the effect of novel copper carbonate (CuCO3) nanoparticles and their targeted delivery to cancer cells in vitro and in vivo. We synthesized the CuCO3 nanoparticles by a precipitation method, and they were characterized using various biophysical techniques. These CuCO3 nanoparticles (18–20 nm) induced DNA damage and disrupted the mitochondrial membrane, and finally cell death was mediated by apoptosis. Additionally, folic acid was conjugated to the CuCO3 nanoparticles, to deliver them specifically to cancer cells. To study the efficacy of the targeting, folate receptor knockdown HeLa cells were developed by sh-RNA and it was also further tested on a mouse model. These folic acid conjugated CuCO3 nanoparticles can be an effective therapeutic agent for folate receptor expressing cancer cells, and can therefore minimize the toxicity to normal cells.