Catalytic supercritical water oxidation of tri-n-butyl phosphate: Process optimization by response surface methodology and cytotoxicity assessment

Catalytic supercritical water oxidation (SCWO) of an organophosphate flame retardant, namely tri-n-butyl phosphate (TNBP) was studied. Firstly, copper oxide nanoparticles (NPs) were synthesized in SCW and their properties were characterized by various analyses. Afterwards, their catalytic performance was investigated under different conditions including reaction temperature (400–500 °C), TNBP volume percentage in the feed (1–4%), oxidant ratio (0–2) and reaction time (50–150 min) based on response surface methodology (RSM). The synthesized CuO NPs had an average particle size of 30 nm with a narrow distribution. According to RSM analysis, the reaction temperature and time are the most significant factors; whereas, the impact of the other factors, especially TNBP volume percentage in the feed, was found to be negligible. Overall, excellent performance was achieved under optimal conditions found by the RSM, which was reaction temperature of 500 °C, TNBP volume percentage of 4%, oxidant ratio of 1.5, and reaction time of 90 min. The TOC removal efficiency as an indicator of TNBP degradation was about 99%. Finally, in vitro cell viability assays for the cytotoxicity evaluation of fresh and SCW-treated solution were applied. The results of MTT showed that SCWO converts TNBP into by-product that did not induce any cytotoxicity.     

Synthesis, Characterization, and Cytotoxicity Analysis of a Biodegradable Polyurethane

A polyester urethane was synthesized for use in a biodegradable scaffold. The polyurethane was synthesized in a two-step process: first, ester diol was synthesized from lactic acid and polyethylene glycol 400 (PEG 400), then it was polymerized with toluene diisocyanate using dibutyl tin dilaurate (DBTDL) as a catalyst to form a polyester urethane. Polyester urethane has tensile strength of 51-59 MPa and elongation at fracture of 369-439%. FTIR and XRD were used to confirm the formation and structure of the polymer. Hydrolytic degradation was studied in different alkali solutions and in saline water. In order to assess the cellular response of this material, cytotoxicity analysis was carried out against the cell line.     

Synthesis of Isocryptolepine-Triazole Adducts and Evaluation of Their Cytotoxic Activity

Eighteen hybrid compounds between 8-bromo-2-fluoro-isocryptolepine ( 4 ) and 1,2,3-triazole were synthesized via azide rearrangement-annulation reaction. Compound 4 underwent regioselective N-propargylation and click reaction to form 8-bromo-2-fluoro-isocryptolepine-triazole hybrids 11 which were evaluated for cytotoxic activity. Compound 11 c containing 1-anisyltriazole was the most effective in inhibiting HepG2, HuCCA-1 and A549 cell lines (IC₅₀ values of 1.65–3.07 μM) while compounds 11 a (1-phenyltriazole), 11 j (1-para-CF₃-benzyltriazole) and 11 l (1-meta-Cl-benzyltriazole) were potent inhibitors of HuCCA-1, HepG2 and A549 cell lines, respectively. Moreover, 11 l showed the lowest cytotoxicity to normal human kidney cell line. Compounds 11 c and 11 l provided improvement of cytotoxic activity over 4 . Compounds 4 , 11 c and 11 l were selected to investigate their mechanisms of action. The results showed that 4 could induce G2/M cell cycle arrest and was involved in the upregulation of p53 and p21 proteins. However, the mechanisms of growth inhibition by 11 c and 11 l were associated with G0/G1 cell cycle arrest and mediated by induction of oxidative stress.     

LHRH-PE40的免疫原性及其抗体对细胞毒作用的影响

目的观察连续静脉注射重组毒素LHRH-PE40所引起的家兔抗LHRH-PE40抗体产生的规律以及该抗体对细胞毒作用的影响。方法将家兔分为3组,第1组隔日连续静脉注射LHRHPE40,第2组用弗氏佐剂乳化的LHRHPE40皮下注射为阳性对照组,第3组静脉注射人血白蛋白为阴性对照组。用ELISA检测血清中的抗体水平,XTT检测LHRH-PE40与血清中和后对Hela细胞的细胞毒作用。结果抗LHRHPE40抗体水平随静脉注射时间的延长而升高,8d可以检测到抗LHRH-PE40抗体,在24d基本达到最高水平。血清中和后LHRHPE40对Hela细胞的半数抑制量较阴性血清提高1～2倍,而阳性血清较阴性血清提高14倍。结论连续静脉注射LHRH-PE40产生较低水平的抗体,这种抗体未造成LHRHPE40对Hela细胞半数抑制量产生严重影响,这为临床连续使用LHRH-PE40提供了依据。     

Efficient Gene Transfection into Mammalian Cells Mediated by Cross-linked Polyethylenimine

25 kDa branched polyethylenimine (PEI) has successfully been used for in vitro and in vivo gene delivery approaches, but it is cytotoxic. Smaller PEIs are usually non-cytotoxic but less efficient. In order to enhance the gene delivery efficiency and minimize cytotoxicity of PEI, we explored to synthesize cross-linked PEIs with degradable bonds by reacting amines of small branched 2000 Da PEI with small diacrylate (1,4-butanediol diacrylate or ethyleneglycol dimethacrylate) for 2–6 hours. The efficiency of the cross-linked PEIs during in vitro delivering plasmid containing enhanced green fluorescent protein (EGFP) gene reporter and their cytotoxicity were assessed in melanoma B16F10 cell and other cell lines. In vivo gene delivery efficiency was evaluated by direct injection delivery of the EGFP plasmid/cross-linked PEI complexes into mice and by estimating the EGFP expression in animal muscles. Compared to commercially available 25-kDa branched PEI, the cross-linked PEIs reported here could mediate more efficient expression of reporter gene than the 25-kDa PEI control, 19-fold more efficiently in B16F10 cells, 17-fold in 293T cells, 2.3-fold in 3T3 cells, and they exhibited essentially nontoxic at their optimized condition for gene delivery. Furthermore the transfection activity of polyplexs was preserved in the presence of serum proteins. The muscle transfected with the cross-linked PEI prepared here exhibited normal morphology and excellent gene expression. The cross-linked PEIs reported here were evidently more efficient than the commercial 25-kD PEI control and had less cytotoxicity in gene delivery in vitro and in vivo.     

Preparation of Adrenochrome Hydrogel Patch, Gel, Ointment, and the Comparison of Their Blood Coagulating and Wound Healing Capability

The aim of this study is to make an effective blood coagulant and wound healing agent, which on its topical application on ruptured skin would help in instant coagulation of blood and ongoing healing of wound. The hydrogel has been prepared by mixing 28% w/v gelatin and 21% w/v PVA in distilled water, and heated to 40°C followed by addition of a blood coagulant at a lower temperature. Beeswax, alcohol, liquid paraffin, and adrenochrome were mixed, triturated, and heated accordingly to prepare adrenochrome ointment. Polyvinyl alcohol and glycerin were mixed and heated and the drug was added at a lower temperature, and stored at 4-5°C to form adrenochrome gel. Gelatin alone has cell adhesion property. Adrenochrome is a blood coagulant. Therefore, gelatin with adrenochrome in hydrogel has a synergistic effect in wound healing. To evaluate the efficacy of these three different formulations, incisions were made on the backs of three mice and simultaneously adrenochrome containing hydrogel patch, gel, and ointment were applied on the wound and observed at regular intervals for half an hour to examine the rate of blood coagulation and kept under observation for 2 days to study the rate of wound healing. The efficacy of all these three formulations was compared to appraise the most effective blood coagulating and wound healing agent.     

Low molecular weight PEI-grafted carboxyl-modified soybean protein as gene carriers with reduced cytotoxicity and greatly improved transfection in vitro

SA-SP-PEI were synthesized via acylation reaction between carboxyl-modified soybean protein (SA-SP) and branched polyethylenimine (PEI) with molecular weight of 600, 1200, and 1800?Da, and designed as SA-SP-PEI600, SA-SP-PEI1200, and SA-SP-PEI1800, respectively. SA-SP-PEI could effectively condense plasmid DNA into nanoscale polyplexes and protect them from enzymatic digestion. MTT assay revealed that SA-SP-PEI exhibited reduced cytotoxicity on 293?T and SH-SY5Y cells. SA-SP-PEI1800/DNA complexes hold highest transfection efficiency on 293?T and SH-SY5Y cells with or without 10% serum, which was owing to its better serum stable and improved biocompatibility. Such polycationic soybean proteins have great potentials as gene carriers by further optimization.     

Aflatoxin B1 degradation by culture and lysate of a Pontibacter specie

The presence of aflatoxin B₁ (AFB₁) along the food chain poses a significant threat, thus propelling the need for an effective approach to control it. This study was therefore, aimed at investigating AFB₁ degradation of liquid cultures and lysates of an isolated Pontibacter sp. (VGF1). Liquid cultures, lysed bacterial cells in the absence (uninhibited lysates) and presence of protease inhibitors (protease inhibited lysates) were respectively incubated with AFB₁ for 3, 6, 12, 24 and 48 h. AFB₁ degradation was monitored during this period on high performance liquid chromatography (HPLC) and results obtained revealed that after 6 h of incubation, the protease inhibited (PI) lysates yielded a 65% AFB₁ degradation, whereas after 12 h, no residual AFB₁ was detected. Conversely, after 48 h of incubation, a significantly (p≤0.05) lower AFB₁ degradation of 50 and 36% by the liquid culture and uninhibited lysate, respectively, were noted. It was further confirmed that the degradation mechanism was enzymatic. Data from cytotoxicity studies against human lymphocytes further demonstrated that extracts of biotransformed AFB₁ were less toxic when compared to that of AFB₁. Findings from this study have demonstrated an alternative approach for the decontamination and biocontrol of AFB₁ in various agricultural commodities.     

Morphological,mechanical, and biological evolution of pure hydroxyapatite and its composites with titanium carbide for biomedical applications

Pure hydroxyapatite (HAp) was synthesized successfully via a wet chemical precipitation method. To study the influence of TiC (weight % of 5, 10, 15) substitution on the mechanical behavior of pure HAp, its composites with TiC were synthesized using a solid-state reaction method. Herein, detailed investigations of pure HAp and its composites using X-ray powder diffraction (XRD), FTIR spectroscopy, Raman spectroscopy, UV-VIS spectroscopy, SEM followed by EDAX and particle size analysis were carried out. XRD study reveals the phase stability of the prepared HAp and composite samples. However, FTIR and Raman spectroscopic studies revealed the bond formation among the various constituents. Mechanical behavior of HAp, and its composites with TiC were studied using numerous parameters like density, Young's modulus, fracture toughness, and load absorption capability. Based on these studies, it was revealed that the addition of 5 wt % substitution of TiC sintered at 1200 °C significantly enhanced the mechanical properties of pure HAp. Hence, 5 wt % of TiC composite 95HAp-5TiC showed the best mechanical characteristics such as density (2.3060 g/cm³), Young's modulus (14.53 MPa), fracture toughness (19.82 MPa m^1/2), maximum compressive strength (186 MPa) respectively. Cytotoxicity and osteogenic activities of the synthesized pure HAp and its composite, 95HAp-5TiC were performed using osteoblast cells (mouse calvarial) at different concentrations of the samples (0.01 μg, - 100 μg). From the above studies, the cell viability and ALP activities of the composite, 95HAp-5TiC found to be excellent than that of pure HAp. Hence, this composite sample may be utilized for bone implant applications.     

Cell membrane disruption induced by amorphous silica nanoparticles in erythrocytes,lymphocytes, malignant melanocytes,and macrophages

It is of critical importance to examine carefully the potential adverse effects of engineered nanoparticles (NPs) on human health and environments. In the present study, we have investigated the disruption of cell membranes induced by amorphous silica NPs in erythrocytes, lymphocytes (Jurkat), malignant melanocytes (B16F10), and macrophages (J774.1); these four types of mammalian cells have distinctive characteristics in terms of nucleated/non-nucleated cells, adherent/non-adherent cells, endocytosis, and phagocytosis. The silica-induced membranolysis was examined by exposing these different cells to serum-free culture media containing the amorphous silica NPs of different diameters (28, 50, 55, 156, and 461 nm) under similar conditions. We investigated how the silica-induced membranolysis of the cells of different origins is influenced by the size and dose of the silica NPs. Additionally, the interaction forces of a silica microsphere with a living cell or a giant unilamellar vesicle composed of zwitterionic phosphatidylcholine lipids were measured by colloid-probe atomic force microcopy, whereby the affinities of silica surface for plasma membranes and protein-free phospholipid membranes were estimated. Possible mechanism of the silica-induced membranolysis was discussed.