Antiviral Activity of Chitosan Nanoparticles and Chitosan Silver Nanocomposites against Alfalfa Mosaic Virus.

Plant viruses are a global concern for sustainable crop production. Among the currently available antiviral approaches, nanotechnology has been overwhelmingly playing an effective role in circumventing plant viruses. Alfalfa mosaic virus (AMV) was isolated and identified from symptomatic pepper plants in Egypt using symptomatology, serological tests using the direct ELISA technique, differential hosts and electron microscopy. The virus was biologically purified from a single local lesion that developed on Chenopodium amaranticolor. The AMV infection was further confirmed using an AMV coat protein-specific primer RT-PCR. We further evaluated the antiviral potential of chitosan nanoparticles (CS-NPs) and chitosan silver nanocomposites (CS-Ag NC) in different concentrations against AMV infections in pepper plants. All tested concentrations of CS-NPs and CS-Ag NC induced the inhibition of AMV systemically infected pepper plants when applied 24 h after virus inoculation. The foliar application of 400 ppm CS-NPs or 200 ppm CS-Ag NC produced the highest AMV inhibitory effect (90 and 91%) when applied 24 h after virus inoculation. Treatment with CS-NPs and CS-Ag NC considerably increased the phenol, proline and capsaicin contents compared to the infected plants. Moreover, the agronomic metrics (plant height, fresh and dry pod weights and number of pods per plant) were also significantly improved. According to our results, the potential applications of CS-NPs and CS-Ag NC may provide an effective therapeutic measure for better AMV and other related plant virus management.

Chitosan-Ocimum basilicum nanocomposite as a dietary additive in Oreochromis niloticus: Effects on immune-antioxidant response, head kidney gene expression, intestinal architecture, and growth.

Several studies have looked into the use of basil, Ocimum basilicum (L.) in aquaculture as a dietary additive; however, more research is needed to see the possibility of it's including in nanocarriers in aquafeeds. An experiment was undertaken to highlight the efficacy chitosan-Ocimum basilicum nanocomposite (COBN), for the first time, on Nile tilapia (Oreochromis niloticus) growth, stress and antioxidant status, immune-related parameters, and gene expression. For 60 days, fish (average weight: 23.55 ± 0.08 g) were fed diets provided with different concentrations of COBN (g/kg): 0 g [COBN0], 1 g [COBN1], 2 g [COBN2], and 3 g [COBN3], where COBN0 was kept as control diet. Following the trial, the fish were challenged with pathogenic bacteria (Aeromonas sobria) and yeast (Candida albicans) infection. In comparison to the control (COBN0), a notable increase in growth parameters (weight gain, feed intake, and specific growth rate) and intestinal morphometric indices (average intestinal goblet cells count, villous width, and length) in all COBN groups was observed, where COBN2 and COBN3 groups had the highest values. The COBN diets significantly (p < 0.05) declined levels of serum triglycerides, glucose, cholesterol, and hepatic malondialdehyde. Moreover, the higher levels of serum biochemical biomarkers (growth hormone, total protein, globulin, and albumin), immunological parameters (phagocytic activity%, nitric oxide, and lysozyme), and hepatic antioxidant parameters (superoxide dismutase, total antioxidant capacity, and glutathione peroxidase) were obvious in the COBN2 and COBN3 groups followed by COBN1. The immune-antioxidant genes (TNF-α, IL-10, IL-1ß, TGF-ß, GPx, and SOD) were found to be considerably up-regulated in all COBN groups (COBN2 and COBN3 followed by COBN1). Fifteen days post-challenge with A. sobria and C. albicans, the highest survival rate was recorded in the COBN2 group (83.33 and 91.67%) followed by the COBN3 group (75 and 83.33%), respectively. The findings showed that a dietary intervention with COBN can promote growth, intestinal architecture, immunity, and antioxidant markers as well as protect O. niloticus against A. sobria and C. albicans infection. As a result, the COBN at a dose of 2 g/kg could be used as a food additive for the sustainable aquaculture industry.

Silica-coated graphene compared to Si-CdSe/ZnS quantum dots: Toxicity, emission stability, and role of silica in the uptake process for imaging purposes.

Quantum dots (QDs) present a special type of nanocrystals (NCs) due to their unique optical and chemical properties. While cadmium-based QDs (Cd-QDs) have the most favorable physicochemical properties, their toxicity, instability in the aqueous phase, and loss of brightness at high temperature are some of the obstacles that prevent the wide use of Cd-QDs. Carbon-based QDs as graphene quantum dots (GQDs) represent a very promising biocompatible replacement. In the present work, we mainly focus on comparing the efficiency and uptake of GQDs and Cd-QDs for fluorescent imaging purposes and studying the effect of growing silica shell on the emission and the uptake of QDs inside living human and bacterial cells. Graphene and CdSe/ZnS QDs were prepared and encapsulated in silica to increase their emission and uptake by living cells. Moreover, we studied their photostability and cytotoxicity. The Prepared G-Si QDs showed good emission inside the cytoplasmic portion of the liver hepatocellular carcinoma cell line (HepG2) and Bacillus subtilis (B. subtilis), but they revealed lower photoluminescence (PL) intensity compared to Si-CdSe/ZnS NCs although G-Si QDs are advantageous in other aspects, i.e. possess lower toxicity and higher stability with temperature variations.

Effects of magnetite nanoparticles on physiological processes to alleviate salinity induced oxidative damage in wheat.

BACKGROUND: One of the major abiotic stressors that have a serious effect on plant growth and productivity worldwide is the salinity of soil or irrigation water. The effect of foliar application of magnetite nanoparticles (size = 22.05 nm) at different concentrations (0, 0.25, 0.5, and 1.0 ppm) was investigated to improve salinity tolerance in two wheat cultivars, namely, Misr1 (Tolerant) and Gimmeza11 (Sensitive). Moreover, toxicological investigations of magnetite oxide nanoparticle in Wistar albino rats were estimated. RESULTS: The magnetite nanoparticles positively affected growth, chlorophyll, and enzymatic antioxidants such as superoxide dismutase (SOD), stimulating reduced glutathione and improving the aggregation of several polypeptide chains that may be linked to the tolerance of saline stress. In contrast, magnetite nanoparticles reduced malondialdehyde (MDA). Inverse sequence-tagged repeat (ISTR) assay of DNA molecular marker showed the change in band numbers with the highest polymorphic bands with 90% polymorphism at primer F3, B5 and 20 positive bands in Gimmeza11 with 0.5 ppm magnetite nanoparticles. In the median lethal dose (LD50 ) study, no rats died after the oral administration of magnetite nanoparticle at different doses. Therefore, the iron oxide nanoparticle was nontoxic when administered orally by gavage. CONCLUSION: Magnetite nanoparticles partially helped to alleviate the effects of salt stress by activating growth, chlorophyll content, SOD, glutathione, and soluble proteins in two wheat cultivars (Misr1 and Gimmeza11) and decreasing MDA content. © 2021 Society of Chemical Industry.

Antiviral Activity of Chitosan Nanoparticles Encapsulating Curcumin Against Hepatitis C Virus Genotype 4a in Human Hepatoma Cell Lines.

PURPOSE: Current direct-acting antiviral agents for treatment of hepatitis C virus genotype 4a (HCV-4a) have been reported to cause adverse effects, and therefore less toxic antivirals are needed. This study investigated the role of curcumin chitosan (CuCs) nanocomposite as a potential anti-HCV-4a agent in human hepatoma cells Huh7. METHODS: Docking of curcumin and CuCs nanocomposite and binding energy calculations were carried out. Chitosan nanoparticles (CsNPs) and CuCs nanocomposite were prepared with an ionic gelation method and characterized with TEM, zeta size and potential, and HPLC to calculate encapsulation efficiency. Cytotoxicity studies were performed on Huh7 cells using MTT assay and confirmed with cellular and molecular assays. Anti-HCV-4a activity was determined using real-time PCR and Western blot. RESULTS: The strength of binding interactions between protein ligand complexes gave scores with NS3 protease, NS5A polymerase, and NS5B polymerase of -124.91, -159.02, and -129.16, for curcumin respectively, and -68.51, -54.52, and -157.63 for CuCs nanocomposite, respectively. CuCs nanocomposite was prepared at sizes 29-39.5 nm and charges of 33 mV. HPLC detected 4% of curcumin encapsulated into CsNPs. IC50 was 8 µg/mL for curcumin and 25 µg/mL for the nanocomposite on Huh7 but was 25.8 µg/mL and 34 µg/mL on WISH cells. CsNPs had no cytotoxic effect on tested cell lines. Apoptotic genes' expression revealed the caspase-dependent pathway mechanism. CsNPs and CuCs nanocomposite demonstrated 100% inhibition of viral entry and replication, which was confirmed with HCV core protein expression. CONCLUSION: CuCs nanocomposite inhibited HCV-4a entry and replication compared to curcumin alone, suggesting its potential role as an effective therapeutic agent.

Toxicopathological and immunological studies on different concentrations of chitosan-coated silver nanoparticles in rats.

BACKGROUND: Much consideration has been paid to the toxicological assessment of nanoparticles prior to clinical and biological applications. While in vitro studies have been expanding continually, in vivo investigations of nanoparticles have not developed a cohesive structure. This study aimed to assess the acute toxicity of different concentrations of chitosan-coated silver nanoparticles (Ch-AgNPs) in main organs, including liver, kidneys, and spleen. MATERIALS AND METHODS: Twenty-eight male albino rats were used and divided into 4 groups (n=7). Group 1 was kept as a negative control group. Groups 2, 3, and 4 were treated intraperitoneally with Ch-AgNPs each day for 14 days at doses of 50, 25, and 10 mg/kg body weight (bwt) respectively. Histopathological, morphometric and immunohistochemical studies were performed as well as oxidative stress evaluations, and specific functional examinations for each organ were elucidated. RESULTS: It was revealed that Ch-AgNPs induced dose-dependent toxicity, and the repeated dosing of rats with 50 mg/kg Ch-AgNPs induced severe toxicities. Histopathological examination showed congestion, hemorrhage, cellular degeneration, apoptosis and necrosis in hepatic and renal tissue as well as lymphocytic depletion with increasing tangible macrophages in the spleen. The highest levels of malondialdehyde, alanine aminotransferase, aspartate aminotransferase (MDA, ALT, AST) and the lowest levels of reduced glutathione, immunoglobulin G, M and total protein (GSH, IgG, IgM, TP) were observed in this group. On the other hand, repeated dosing with 25 mg/kg induced mild to moderate disturbance in the previous parameters, while there was no significant difference in results of pathological examination and biochemical tests between the control group and those treated with 10 mg/kg bwt Ch-AgNPs. CONCLUSION: Chitosan-coated silver nanoparticles induce dose-dependent adverse effects on rats.

Synthesis, Characterization and Cytotoxic Evaluation of Graphene Oxide Nanosheets: In Vitro Liver Cancer Model

Background: Graphene nanosheets have a broad spectrum of biomedical applications. Hepatocellular cancer (HCC) is a major health problem in the Egyptian population. Currently, treatment strategies are invasive and have several adverse side effects. Thus, other approaches are required for managing this aggressive type of cancer. Our objective here was to prepare and characterize graphene oxide nanosheets and evaluate cytotoxic effect at the molecular level in an in vitro human liver cancer cell model (HepG2). Methods: Graphene oxide nanosheets were generated by chemical oxidation and characterized by transmission electron microscopy and X-ray diffraction. Cytotoxic effects in HepG2 cells were monitored by sulforhodamine B (SRB) colorimetric assay followed by flow cytometric analysis. Molecular investigations of DNA fragmentation and expression of some apoptotic genes at the transcriptional RNA level were also performed. Results: Treatment of HepG2 cells with 400µg/ml graphene oxide nanosheets showed alteration in cell morphology after 24 h. Flow cytometry revealed accumulation of cells in S phase of cell cycle followed by dramatic effects on cellular DNA. Extensive evaluation of the cytotoxic effects of graphene oxide showed increased mRNA Bax apoptotic gene expression with not of P53 and caspase-3 mRNA after 24h, suggesting involvement of an intrinsic apoptotic caspase-independent pathway. Conclusion. Graphene oxide can mediate apoptotic gene signaling in human liver cancer cells opening a novel approach to cancer management. Further analyses at the molecular level are now required to confirm our results and facilitate biomedical applications in vivo.