Green Synthesized Silver Nanoparticles Using Feijoa Sellowiana Leaf Extract, Evaluation of Their Antibacterial, Anticancer and Antioxidant Activities.

Biogenic synthesis of silver nanoparticles (SNPs) has great attention of scientists, as it provides clean, biocompatible, non-toxic and inexpensive fabrication. In this study, F. sellowiana leaf extract was used for synthesizing SNPs which reduces silver nitrate into silver zero-valent. SNPs were characterized by UV, FTIR, XRD, SEM-EDS, and TEM analysis. They were also examined for their biological activities. The presence of biosynthesized SNPs was characterized by UV-visible spectroscopy and also crystal nature of SNPs was identified with XRD analysis. FT-IR spectrum was used to confirm the presence of different functional groups in the biomolecules which act as a capping agent for the nanoparticles. The morphology of SNPs was explored using SEM and the presence of silver was confirmed by elemental analysis. The size of the nanoparticles was in the range of 20-50 nm determined by TEM. The green synthesized SNPs showed good antibacterial activities against both gram-negative and gram-positive bacteria and also in resistant clinically isolated pathogens. Furthermore, the green synthesized SNPs showed reliable anticancer activity on the gastric adenocarcinoma (AGS) and breast (MCF-7) cancer cell lines with little effect on normal (HFF) cells. The in-vitro antioxidant activity of SNPs showed a significant effect on the scavenging of free radicals and iron chelating activity.

Poly Lactic-co-Glycolic Acid Nanoparticles Containing Human Gastric Tumor Lysates as Antigen Delivery Vehicles for Dendritic Cell-Based Antitumor Immunotherapy.

Stimulating antitumor T cells using dendritic cells (DCs) is a novel and promising method in cancer therapy. Poly lactic-co-glycolic acid is one of the best-known polymers used for encapsulating antigen to protect them against proteolytic enzymes. In this study, poly lactic-co-glycolic acid nanoparticles (NPs) were used as DC antigen delivery vehicles in a preclinical model of immunotherapy of gastric cancer. The DCs were generated from peripheral blood monocytes by conventional in vitro differentiation and loaded with either soluble tumor lysate or lysate encapsulated in NPs using a double emulsion/solvent evaporation technique. Morphology of NPs was determined by scanning electron microscopy. Tumor lysate, either in the soluble form or encapsulated in NPs, was loaded into DC and stimulatory capacity was compared using patient-derived autologous CD3+ T cells as responders. The amount of relevant cytokines produced by Ag-loaded DC and in DC/T cell cocultures was evaluated as a measure of initial DC stimulation and T-cell responses, respectively. Significance increases in expression of DC surface molecules (i.e., CD80, CD83, CD86, and Human Leukocyte Antigen-DR (HLA-DR)) and cytokine production by both DC and DC/T cell cocultures (i.e., interleukin (IL)-12:IL-10 and interferon [IFN]-γ:IL-4 ratios) was observed following loading with lysate NP versus controls. The results suggest that NP-encapsulated antigen can shift antitumor T-cell responses toward a Th1 bias, which potentially increases DC vaccine potency in clinical settings.

Enhanced stimulation of anti-breast cancer T cells responses by dendritic cells loaded with poly lactic-co-glycolic acid (PLGA) nanoparticle encapsulated tumor antigens.

BACKGROUND: Developing safe and effective cancer vaccine formulations is a primary focus in the field of cancer immunotherapy. Dendritic cells (DC) are currently employed as cellular vaccine in clinical trials of tumor immunotherapy. Recognizing the critical role of DCs in initiating anti-tumor immunity has resulted in the development of several strategies that target vaccine antigens to DCs to trigger anti-tumor T cell responses. To increase the efficiency of antigen delivery systems for anti-tumor vaccines, encapsulation of tumor-associated antigens in polymer nanoparticles (NPs) has been established. METHODS: In this study, the effect of tumor lysate antigen obtained from three stage III breast cancer tissues encapsulated within PLGA NPs to enhance the DC maturation was investigated. The T-cell immune response activation was then fallowed up. Fresh breast tumors were initially used to generate tumor lysate antigens containing poly lactic-co-glycolic acid (PLGA) NP. The encapsulation efficiency and release kinetics were profiled. The efficiency of encapsulation was measured using Bradford protein assays measuring the dissolved NPs. The stability of released antigen from NPs was verified using SDS-PAGE. To evaluate the hypothesis that NPs enhances antigen presentation, including soluble tumor lysate, tumor lysate containing NPs and control NPs the efficiency of NP-mediated tumor lysate delivery to DCs was evaluated by assessing CD3+ T-cell stimulation after T cell/and DCs co-culture. RESULTS: The rate of encapsulation was increased by enhancing the antigen concentration of tumor lysate. However, increasing the antigen concentration diminished the encapsulation efficiency. In addition, higher initial protein contenting NPs led to a greater cumulative release. All three patients released variable amounts of IFN-γ, IL-10, IL-12 and IL-4 in response to re-stimulation. T cells stimulated with lysate-pulsed DCs induced a substantial increase in IFN-γ and IL-12 production. We demonstrated that NPs containing tumor lysate can induce maturation and activation of DCs, as antigen alone does. CONCLUSION: PLGA-NPs are attractive vehicles for protein antigen delivery which effectively induce stimulation and maturation of DCs, allowing not only an enhanced antigen processing and immunogenicity or improved antigen stability, but also the targeted delivery and slow release of antigens.

Extraction optimization of polycyclic aromatic hydrocarbons by alcoholic-assisted dispersive liquid-liquid microextraction and their determination by HPLC.

A sensitive method for the extraction and determination of polycyclic aromatic hydrocarbons (PAHs) using alcoholic-assisted dispersive liquid-liquid microextraction (AA-DLLME) and HPLC was developed. The extraction procedure was based on alcoholic solvents for both extraction and dispersive solvents. The effective parameters (type and volume of extraction and dispersive solvents, amount of salt and stirring time) on the extraction recovery were studied and optimized utilizing factorial design (FD) and central composite design (CCD). The best recovery was achieved by FD using 2-ethyl-1-hexanol as the extraction solvent and methanol as the dispersive solvent. The results showed that volume of dispersive solvent and stirring time had no effect on the recovery of PAHs. The optimized conditions were 145 µL of 2-ethyl-1-hexanol as the extraction solvent and 4.2% w/v of salt (NaCl) in sample solution. The enrichment factors of PAHs were in the range of 310-325 with limits of detection of 0.002-0.8 ng/mL. The linearity was 0.01-800 ng/mL for different PAHs. The relative standard deviation (RSD) for intra- and inter-day of extraction of PAHs were in the range of 1.7-7.0 and 5.6-7.3, respectively, for five measurements. The method was also successfully applied for the determination of PAHs in environmental water samples.