Satyajit Tripathy

Synthesis, characterization of chitosan–tripolyphosphate conjugated chloroquine nanoparticle and its in vivo anti-malarial efficacy against rodent parasite: A dose and duration dependent approach

Various strategies to deliver antimalarials using nanocarriers have been evaluated. However, taking into account the peculiarities of malaria parasites, the focus is placed mainly polymer-based chitosan nanocarriers. Our purpose of the study is to develop chitosan-tripolyphosphate (CS-TPP) nanoparticles (NPs) conjugated chloroquine in application for attenuation of Plasmodium berghei infection in Swiss mice. NPs were prepared by ionotropic gelation between CS and sodium TPP. In the study, the interaction of CS and TPP and the presence of chloroquine at the surface of chitosan-TPP NPs have been investigated by means of different methods like FTIR, DLS, and zeta potential. After drug preparation, effective dose of the nanoconjugated chloroquine (Nch) among 100, 250, and 500 mg/kg bw/day, was studied against P. berghei infection in Swiss mice by blood smear staining and biochemical assay of different inflammatory markers, and antioxidant enzyme levels also performed. After evaluating the effective dose, dose-dependent duration study was performed for 5, 10, 15 days. From the present study the maximum effect of Nch was found at 250 mg/kg bw concentration for 15 days treatment. So, this Nch might have potential of application as therapeutic anti-malarial and antioxidant agent.

Toxicity of cobalt oxide nanoparticles to normal cells; an in vitro and in vivo study

The aim of this study was to find out the intracellular signaling transduction pathways involved in cobalt oxide nanoparticles (CoO NPs) mediated oxidative stress in vitro and in vivo system. Cobalt oxide nanoparticles released excess Co++ ions which could activated the NADPH oxidase and helps in generating the reactive oxygen species (ROS). Our results showed that CoO NPs elicited a significant (p<0.05) amount of ROS in lymphocytes. In vitro pretreatment with N-acetylene cystine had a protective role on lymphocytes death induced by CoO NPs. In vitro and in vivo results showed the elevated level of TNF-α after CoO NPs treatment. This TNF-α phosphorylated the p38 mitogen-activated protein kinase followed by activation of caspase 8 and caspase 3 which could induce cell death. This study showed that CoO NPs induced oxidative stress and activated the signaling pathway of TNF-α-caspase-8-p38-caspase-3 to primary immune cells. This study suggested that bare CoO NPs are a toxic for primary human immune cells that deals directly with human health. Surface modification or surface functionalization may open the gateway for further use of CoO NPs in different industrial use or in biomedical sciences.

A ZnO decorated chitosan–graphene oxide nanocomposite shows significantly enhanced antimicrobial activity with ROS generation

The rise in antimicrobial resistance requires the development of new antibacterial agents. Herein, we develop nanocomposites by growing zinc oxide nanoparticles on the surface of chitosan (CS) modified graphene oxide (GO), obtaining GO@CS/ZnO as a novel antibacterial material. The crystal structures, surface functional groups and morphology were analyzed by using X-ray diffraction (XRD) pattern, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) images, respectively. The Minimum Inhibitory Concentration (MIC) and the Minimum Bactericidal Concentration (MBC) of GO@CS/ZnO show more antibacterial potency towards both Gram-negative bacteria Escherichia coli (E. coli) and Gram-positive bacteria Staphylococcus aureus (S. aureus). In this study the GO@CS/ZnO expresses its more potency than reported graphene based nanocomposites. Investigation of intercellular reactive oxygen species (ROS) generation, NO generation and catalase activity in E. coli and S. aureus reveal that GO@CS/ZnO treatment also augments the intracellular bacterial killing by inducing reactive oxygen species production that causes oxidative damage. The minimal inhibition concentrations (MIC) of GO@CS/ZnO against E. coli and S. aureus are only 2.5 μg mL−1 and 5 μg mL−1 respectively. Compared with graphene based nanocomposite, which have been widely used as antibacterial agents, our GO@CS/ZnO shows better antibacterial effect. We envision that this study offers novel insights into antimicrobial actions and also demonstrates GO@CS/ZnO is a novel class of topical antibacterial agent in the areas of healthcare and environmental engineering.

Single step synthesis of carbon dot embedded chitosan nanoparticles for cell imaging and hydrophobic drug delivery

The florescent carbon dot conjugated chitosan nanoparticles are developed for the cellular imaging and delivery of poorly water soluble drug telmisartan (TEL). In this work, the florescent chitosan nanoparticles are synthesized in a single step. The presence of surface functional groups and conjugation of the nanoparticles are investigated by FTIR spectroscopy. Dynamic light scattering and TEM analysis are performed to determine the size of the nanoparticles. To investigate the surface morphology FESEM analysis is also performed. The cytotoxicity of the nanoparticles is examined by MTT assay using normal lymphocytes and KG1A cancer cell lines. The intracellular cellular uptake is studied by fluorescence microscopy and flow cytometry analysis. The interactions between the nanoparticles and the drug are investigated by Gaussian 09 and visualized by GaussView 5 program package.

Anticancer and immunostimulatory role of encapsulated tumor antigen containing cobalt oxide nanoparticles

The purpose of this study is to evaluate the prospect of using surface modified cobalt oxide(CoO) nanoparticles as carriers of cancerantigens to human macrophages. N-Phosnomethyliminodiacetic acid (PMIDA) was used for surface modification to overcome the toxic effect of CoO nanoparticles. Here, the phosphonate group of the PMIDA acts as a surface-anchoring agent and the remaining –COOH groups bind nonspecifically with tumor associated antigens. This modification allows the conjugation of human oral carcinoma (KB) cell lysate (CL) as an antigen with PMIDA coated CoO nanoparticles (CL–PMIDA–CoO). Particle characterization was performed by dynamic light scattering, atomic force microscopy, and scanning electron microscopy studies. Fourier transform IR spectroscopy was used to investigate conjugation of the protein with nanoparticles. Protein encapsulation was confirmed by protein gel electrophoresis. Active uptake of antigen-conjugated nanoparticles by macrophages was confirmed by fluorescence microscopy. The antitumor activity of the nanocomplex pulsed macrophages was investigated on a human oral carcinoma cell line (KB) in vitro. The modified nanocomplexes upregulate IFN-γ and TNF-α and induce an anticancer immune response by activating macrophages. The use of TNF-α inhibitor confirmed the ability of the CL–PMIDA–CoO nanocomplex to stimulate TNF-α mediated immunostimulation. CL–PMIDA–CoO nanoparticles efficiently increased the CD4+ population. Thus, our findings provide insight into the use of PMIDA coated CoO nanoparticles as antigen delivery vehicles.Graphical abstract

Chitosan-modified cobalt oxide nanoparticles stimulate TNF-α-mediated apoptosis in human leukemic cells

The objective of this study was to develop chitosan-based delivery of cobalt oxide nanoparticles to human leukemic cells and investigate their specific induction of apoptosis. The physicochemical properties of the chitosan-coated cobalt oxide nanoparticles were characterized using transmission electron microscopy, dynamic light scattering, X-ray diffraction, and Fourier transform infrared spectroscopy. The solubility of chitosan-coated cobalt oxide nanoparticles was higher at acidic pH, which helps to release more cobalt ions into the medium. Chitosan-coated cobalt oxide nanoparticles showed good compatibility with normal cells. However, our results showed that exposure of leukemic cells (Jurkat cells) to chitosan-coated cobalt oxide nanoparticles caused an increase in reactive oxygen species generation that was abolished by pretreatment of cells with the reactive oxygen species scavenger N-acetyl-l-cysteine. The apoptosis of Jurkat cells was confirmed by flow-cytometric analysis. Induction of TNF-α secretion was observed from stimulation of Jurkat cells with chitosan-coated cobalt oxide nanoparticles. We also tested the role of TNF-α in the induction of Jurkat cell death in the presence of TNF-α and caspase inhibitors. Treatment of leukemic cells with a blocker had a greater effect on cancer cell viability. From our findings, oxidative stress and caspase activation are involved in cancer cell death induced by chitosan-coated cobalt oxide nanoparticles.Graphical abstract

A novel chitosan based antimalarial drug delivery against Plasmodium berghei infection.

Chitosan is a natural polysaccharide that has attracted significant scientific interest during the last two decades and chitosan based nanodrug delivery systems seem to be a hopeful and viable strategy for improving disease treatment. This study aims to evaluate the potency of the polymer based nanochloroquine in application for attenuation of Plasmodium berghei infection in Swiss mice and effectiveness against the parasite induced oxidative stress and deoxyribo nucleic acid (DNA) damage in lymphocytes. Nanoparticle was prepared by ionotropic gelation between chitosan and sodium tripolyphosphate. The chloroquine was treated by the actual drug content of effective nanochloroquine and the nanodrug was charged with its effective dose for fifteen days, after successive infection development in Swiss mice. Gimsa staining of thin smear and flow cytometry analysis was pursued to reveal the parasitemia. Different oxidative markers, inflammatory markers, antioxidant enzymes level and also lymphocytic deoxyribo nucleic acid damage study were performed. The present study reveals the potency of the nanodrug which has been found as more prospective than only chloroquine treatment to combat the parasite infection, oxidative stress as well as inflammation and DNA damage. From the study, we conclude this nanodrug may be applicable as potent therapeutic agent than only chloroquine.

Cobalt oxide nanoparticles induced oxidative stress linked to activation of TNF-α/caspase-8/p38-MAPK signaling in human leukemia cells.

The purpose of this study was to determine the intracellular signaling transduction pathways involved in oxidative stress induced by nanoparticles in cancer cells. Activation of reactive oxygen species (ROS) has some therapeutic benefits in arresting the growth of cancer cells. Cobalt oxide nanoparticles (CoO NPs) are an interesting compound for oxidative cancer therapy. Our results showed that CoO NPs elicited a significant (P <0.05) amount of ROS in cancer cells. Co‐treatment with N‐aceyltine cystine (an inhibitor of ROS) had a protective role in cancer cell death induced by CoO NPs. In cultured cells, the elevated level of tumor necrosis factor‐alpha (TNF‐α) was noted after CoO NPs treatment. This TNF‐α persuaded activation of caspase‐8 followed by phosphorylation of p38 mitogen‐activated protein kinase and induced cell death. This study showed that CoO NPs induced oxidative stress and activated the signaling pathway of TNF‐α‐Caspase‐8‐p38‐Caspase‐3 to cancer cells. Copyright

Folate decorated delivery of self assembled betulinic acid nano fibers: a biocompatible anti-leukemic therapy

The objective of this study was to develop folate receptor mediated delivery of self assembled betulinic acid nano fibers (SA-BA) to human leukemic cells and to investigate their specific induction of apoptosis. The physicochemical properties of PEG conjugated SA-BA followed by conjugated with folic acid (FA–PEG–SA-BA) were examined using Fourier transform infrared spectroscopy, thermogravimetry analysis, X-ray diffraction analysis, thin layer chromatography and scanning electron microscopy. The stability of folic acid with PEG–SA-BA conjugate was higher at acidic pH, which helps to maintain the conjugate structure for internalization of folate receptor over expressing cells. FA–PEG–SA-BA showed good compatibility with normal cells. The internalization of FA–PEG–SA-BA was significantly observed in folate receptor over expressing K562 cells while showing comparatively lower impact on folate receptor lower expressing KG-1A cells. This intracellular localization of conjugate facilitated the generation of excess reactive oxygen species (ROS), followed by elevation of tumor necrosis factor alpha (TNF-α) secretion. The effective contribution of ROS and TNF-α in FA–PEG–SA-BA mediated leukemic cell death was confirmed by pretreatment of cells with the ROS scavenger (N-acetyl-L-cysteine) and pentoxifylline, a potent TNF-α blocker. The mode of leukemic cell death was confirmed by flow-cytometric analysis. We also tested the possible involvement of caspase activation in TNF-α mediated leukemic cell death by immunoflouroscence staining of apoptotic marker proteins (caspase 8 and caspase 3).

Internalization of Staphylococcus aureus in Lymphocytes Induces Oxidative Stress and DNA Fragmentation: Possible Ameliorative Role of Nanoconjugated Vancomycin

Staphylococcus aureus is the most frequently isolated pathogen causing bloodstream infections, skin and soft tissue infections and pneumonia. Lymphocyte is an important immune cell. The aim of the present paper was to test the ameliorative role of nanoconjugated vancomycin against Vancomycin-sensitive Staphylococcus aureus (VSSA) and vancomycin-resistant Staphylococcus aureus (VRSA) infection-induced oxidative stress in lymphocytes. VSSA and VRSA infections were developed in Swiss mice by intraperitoneal injection of 5 × 106 CFU/mL bacterial solutions. Nanoconjugated vancomycin was adminstrated to VSSA- and VRSA-infected mice at its effective dose for 10 days. Vancomycin was adminstrated to VSSA- and VRSA-infected mice at a similar dose, respectively, for 10 days. Vancomycin and nanoconjugated vancomycin were adminstrated to normal mice at their effective doses for 10 days. The result of this study reveals that in vivo VSSA and VRSA infection significantly increases the level of lipid peroxidation, protein oxidation, oxidized glutathione level, nitrite generation, nitrite release, and DNA damage and decreases the level of reduced glutathione, antioxidant enzyme status, and glutathione-dependent enzymes as compared to control group, which were increased or decreased significantly near to normal in nanoconjugated vancomycin-treated group. These findings suggest the potential use and beneficial role of nanoconjugated vancomycin against VSSA and VRSA infection-induced oxidative stress in lymphocytes.