Qiqing Zhang

ROS and NF-kappa B are involved in upregulation of IL-8 in A549 cells exposed to multi-walled carbon nanotubes

Carbon nanotubes (CNTs) have potential applications in biosensors, tissue engineering, and biomedical devices because of their unique physico-chemical, electronic and mechanical properties. However, there is limited literature data available concerning the biological properties and toxicity of CNTs. This study aimed to assess the toxicity exhibited by multi-walled CNTs (MWCNTs) and to elucidate possible molecular mechanisms underlying the biological effects of MWCNTs in A549 cells. Exposing A549 cells to MWCNTs led to cell death, changes in cell size and complexity, reactive oxygen species (ROS) production, interleukin-8 (IL-8) gene expression and nuclear factor (NF)-kappaB activation. Treatment of A549 cells with antioxidants prior to adding MWCNTs decreased ROS production and abrogated expression of IL-8 mRNA. Pretreatment of A549 cells with NF-kappaB inhibitors suppressed MWCNTs-induced IL-8 mRNA expression. These results indicate that MWCNTs are able to induce expression of IL-8 in A549 cells, at least in part, mediated by oxidative stress and NF-kappaB activation.

Both FA- and mPEG-conjugated chitosan nanoparticles for targeted cellular uptake and enhanced tumor tissue distribution

Both folic acid (FA)- and methoxypoly(ethylene glycol) (mPEG)-conjugated chitosan nanoparticles (NPs) had been designed for targeted and prolong anticancer drug delivery system. The chitosan NPs were prepared with combination of ionic gelation and chemical cross-linking method, followed by conjugation with both FA and mPEG, respectively. FA-mPEG-NPs were compared with either NPs or mPEG-/FA-NPs in terms of their size, targeting cellular efficiency and tumor tissue distribution. The specificity of the mPEG-FA-NPs targeting cancerous cells was demonstrated by comparative intracellular uptake of NPs and mPEG-/FA-NPs by human adenocarcinoma HeLa cells. Mitomycin C (MMC), as a model drug, was loaded to the mPEG-FA-NPs. Results show that the chitosan NPs presented a narrow-size distribution with an average diameter about 200 nm regardless of the type of functional group. In addition, MMC was easily loaded to the mPEG-FA-NPs with drug-loading content of 9.1%, and the drug releases were biphasic with an initial burst release, followed by a subsequent slower release. Laser confocal scanning imaging proved that both mPEG-FA-NPs and FA-NPs could greatly enhance uptake by HeLa cells. In vivo animal experiments, using a nude mice xenograft model, demonstrated that an increased amount of mPEG-FA-NPs or FA-NPs were accumulated in the tumor tissue relative to the mPEG-NPs or NPs alone. These results suggest that both FA- and mPEG-conjugated chitosan NPs are potentially prolonged drug delivery system for tumor cell-selective targeting treatments.

PLA Nanoparticles Loaded With an Active Lactone Form of Hydroxycamptothecin: Development, Optimization, and In Vitro-In Vivo Evaluation in Mice Bearing H22 Solid Tumor

Hydroxycamptothecin (HCPT)‐loaded PLA nanoparticles were prepared by a one‐step method using the direct dialysis technique, and were examined for particle characteristics, in vitro drug release, and cytotoxicity, as well as antitumor efficiency. Three main influential factors based on the results of a single‐factor test, i.e., PLA concentration, ratio of HCPT to PLA (wt/wt), and dialysis bags with different molecule weight cutoffs, were evaluated using an orthogonal design, giving nanoparticles an average diameter of ∼226.8 nm with smooth surface, modest drug entrapment efficiency (65.15%), and fine drug‐loading content (5.16%, w/w). HCPT was in a crystalline state within the particles. In vitro drug release studies exhibited a slow and prolonged release profile over a period of 30 days. The cytotoxicity test on BEL‐7402 cells indicated that the HCPT‐PLA nanoparticles were more cytotoxic than commercially available HCPT injection. When the antitumor effect was examined by i.v. administration to mice bearing H22 solid tumor, HCPT‐PLA nanoparticles showed a significant suppression of tumor growth without loss of body weight. These results suggest that HCPT‐PLA nanoparticles prepared by the dialysis technique present desirable characteristics for sustained drug delivery and are potentially useful to enhance the antitumor efficacy of HCPT. Drug Dev Res 72: 337–345, 2011.

Preparation and Evaluation of Implantable Chitosan-Collagen-Soybean Phosphatidylcholine Film Impregnated with Mitomycin C-PLA- Nanoparticles

This study was designed to develop and evaluate a chitosan-collagen-soybean phosphatidylcholine (SPC) complex film impregnated with mitomycin C (MMC)-PLA- nanoparticles for treatment of hepatocellular carcinoma in mice. MMC-PLA- nanoparticles were prepared by a reverse micelle-solvent evaporation method. PLA-MMC-nanoparticles were dispersed throughout the film. SEM, ATR-FTIR were used to character the properties of the complex film. In vitro, MMC release from the MMC contained complex film (MMC-film) was measured by incubation of the film in phosphate buffered saline with drug analysis by using UV/vis spectrometer at 366 nm. The MMC-film exhibited release characteristics with 8.01% of MMC being released at 1d and an accumulated drug release over 30 d was 40.32%. In vivo, the MMC-film was implanted at subcutaneous tumor sites of mice and the curative effect was compared with those of drug free complex film. The growth of the tumors were inhibited considerably and dose-dependently by MMC-film (P<0.05). In addition, the post-mortem visual examination did not show any signs of internal inflammation and infection nor were there any evidence of implant encapsulation in any of the animals after 20 d of implantation of the MMC-film or drug free complex film. The results of this work suggest that the chitosan-collagen- SPC complex film has the potential to serve as an effective delivery system for MMC. .

Optimization of Production of PLA Microbubble Ultrasound Contrast Agents for Hydroxycamptothecin Delivery

In this paper, ultrasound contrast agents based on a high molecular polymer-poly lactic acid (PLA) and loaded with hydroxycamptothecin (HCPT) were prepared by combining ultrasound method and a Shirasu porous glass (SPG) membrane emulsification technique. A special focus was on the optimization of production of HCPT-PLA microbubbles. Different factors, such as the power and the time of ultrasonic action, the ratio of inner aqueous phase against outer oil phase, and the concentration of PLA were evaluated, and the average size of HCPT-PLA microbubbles, the drug carrying efficiency, as well as the acoustically- triggered drug release at 3 kHz ultrasound were determined. The study showed that the HCPT-PLA microbubbles prepared using our optimized conditions, were sphere-like in shape with a mean diameter of 1-7 mum. The drug loading efficiency reached up to 56.48% In vitro, the drug release of HCPT-PLA microbubbles increased significantly at 3 kHz ultrasound for 30 s compared with that of ultrasound-free condition. In conclusion, the HCPT-PLA microbubbles has the characteristics desirable for an intravenously administered ultrasound contrast agent for further clinical use.

Oxidative Stress-Mediated Pro-Inflammatory Responses in Lung Epithelial Cells Exposed to Multi-Walled Carbon Nanotubes

Reactive oxygen species (ROS) and activation of redox-sensitive transcription factors such as nuclear factor (NF)-kB have been implicated in pro-inflammatory responses induced by nanoparticles. However, there is still only little knowledge about the pro-inflammatory responses induced by multi-walled carbon nanotubes (MWCNTs). The objective of the present study was to compare the ability of MWCNTs and carbon black (CB) nanoparticles to induce secretion of pro-inflammatory cytokines and to explore possible mechanisms in A549 lung epithelial cells. Exposure of A549 cells to MWCNTs, but not to CB, resulted in a significant increase in interleukin-8 (IL-8) release and gene expression. MWCNTs stimulated NF-kB DNA binding activity, nuclear translocation of the p65 subunit of NF-kB, IkBa&#61537; &#61472;phosphorylation, and ROS generation in A549 cells. MWCNTs-induced IL-8 gene expression and NF-kB activation were abrogated in the presence of ROS scavengers. These results suggest that MWCNTs are able to induce pro-inflammatory responses and NF-kB activation in A549 cells mediated by ROS generation.

Design of a Smart Transdermal Insulin Drug Delivery System

In this paper, a micro-needle array combined with transdermal delivery, as well as the detection of micro-sensors intelligent transdermal insulin delivery systems was designed with characteristics of pain-free, smart, timing, positioning, quantitative drug delivery. Transdermal delivery of the requirements for the design of the transdermal delivery of the microneedle array structure, and UV-LIGA process for the production of polymer micro-needle technology are discussed. Painless and accurate test in accordance with the needs of blood glucose concentration was designed transdermal detection of subcutaneous tissue fluid glucose concentration of micro-glucose sensor, and its manufacturing process are discussed. Combination of sensor signal processing and administration needs to control the systems signal processing and control circuit for a preliminary design.

Preparation and Characterization of PLA Ultrasound Contrast Agents by Combining an Ultrasound Method and a Shirasu Porous Glass (SPG) Membrane Emulsification Technique

The ultrasound contrast agent based on a poly lactic acid (PLA) was prepared by combining an ultrasound method and a Shirasu Porous Glass (SPG) membrane emulsification technique. An aqueous phase containing ammonium bicarbonate was used as the internal water phase (Wi), and PLA and Span 80 were dissolved in a solvent of dichloromethane (DCM), which was used as the oil phase (O). These two solutions were probe sonicated to form a Wi/O primary emulsion. The primary emulsion was permeated through the uniform pores (1.1 mum) of an SPG membrane into the external water phase (W2) by the pressure of nitrogen gas to form the uniform W1/O/W2 droplets. After DCM was evaporated, the hardened PLA microcapsules were further formulated into a lyophilized powder containing decafluorobutane gas. SEM image demonstrated that the PLA microcapsules were sphere-shaped and internally hollow with an average diameter ranging from 1.99 to 3.58 mum. In vitro, the PLA contrast agents showed high acoustic enhancement properties, the enhancement increased nonlinearly with dose, and the minimal loss (less than 5 dB) of signal was observed over 20 min of analysis at 37degC, the maximum acoustic enhancement was 45 dB, which significantly higher (p < 0.01) compared to a value of 28 dB for those prepared by a conventional solvent evaporation method. In conclusion, the hollow PLA microcapsules prepared by the novel method have the characteristics desirable for an intravenously administered ultrasound contrast agents.

Potential Roles of ROS and NF-kappaB in TNF-alpha Release in Rat Alveolar Macrophages Exposed to Single-Walled Carbon Nanotubes

The pulmonary toxicology of carbon nanotubes (CNTs) was highlighted recently when single-walled carbon nanotubes (SWCNTs) were reported to be highly toxic and fibrotic in mice and in rats when administered by intratracheal instillation. Therefore, it is necessary to evaluate the effects of SWCNTs on human health and the environment before utilizing them on a large scale. The purpose of this study was designed to assess the effects of SWCNTs on tumor necrosis factor-α (TNF-α) release and to elucidate possible molecular mechanisms in primary rat alveolar macrophages as a model system. Our results showed exposure of the cultured alveolar macrophages to SWCNTs elicited a concentration-dependent TNF- α release and reactive oxygen species (ROS) production in alveolar macrophages. In the presence of the antioxidants N-acetyl-Lcysteine (NAC) and glutathione (GSH), the SWCNTs-induced of TNF- α release and ROS production was significantly reduced. SWCNTs treatment caused an activation of the redox-sensitive transcription factor nuclear factor-kappaB (NF-κB). Pretreatment of alveolar macrophages with NF-κB inhibitors, L-1-tosylamido-2-phenylethyl chloromethyl ketone (TPCK) and parthenolide, suppressed SWCNTs-induced TNF-α expression. These results indicate that SWCNTs are able to induce TNF-α release in rat primary alveolar macrophages, at least in part, mediated by oxidative stress and NF- κB activation.

Toxicity Study of Oral Vanadyl Sulfate by NMR-based Metabonomic

Vanadium compounds have been believed to be ideal drugs for diabetes biological therapy in future, but they suffer setback for the potential toxicity now. Toxicity study is necessary for vanadyl drugs development. This paper investigated the toxicity effects of vanadyl sulfate (VOSO4) oral administration in male Wistar rats using 1H NMR-based metabonomic analysis and clinical biochemical analysis. Rat urine were collected and their 1H NMR spectra were acquired, and then subjected to multi-variable statistical analysis. Compared to control groups, urinary excretion of lactate, TMAO, creatinine, taurine and hippurate increased following VOSO4 dosing, with concomitant decrease in the level of acetate and succinate. The dosed groups can be readily discriminated from the control groups by principle component analysis. The results showed that VOSO4 can affect energy metabolism process, interrupted intestinal microfloral metabolism, and induced liver and kidney injury. NMR-based metabonomic can offer additional information to traditional clinical chemistry in the sensitivity and specificity of results obtained.