Confined synthesis of a cis-isotactic ladder polysilsesquioxane by using a pi-stacking and H-bonding superstructure.
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Journal Article↗
Biomedical subjects
Chuanfeng Zhu
Publications and source records attributed to Chuanfeng Zhu.
Antioxidative function and biodistribution of [Gd@C82(OH)22]n nanoparticles in tumor-bearing mice.
Oxidative stress is considered to be one of the important mechanisms involved in carcinogenesis. In our previous study, gadolinium endohedral metallofullerenol ([Gd@C82(OH)22]n nanoparticles) have shown high inhibitory activity on hepatoma cell (H22) growth in mice. To explore the antioxidative functions of nanoparticles, we investigated the biodistribution of [Gd@C82(OH)22]n nanoparticles, the changes of blood coagulation profiles, the metabolism of reactive oxygen species (ROS) in the tumor-bearing mice as well as the possible relationships between nanoparticles treatment and ROS production in this paper. The activities of hepatic superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), glutathione S-transferase (GST) and catalase (CAT) as well as the levels of reduced glutathione (GSH), protein-bound thiols and malondialdehyde (MDA) were compared between the tumor-bearing mice and normal mice. Transplanted tumors were grown in mice by subcutaneous injection of murine hepatoma cells in the mice. The comparison of the above parameters between nanoparticles and cyclophosphamide (CTX) therapy were also investigated. [Gd@C82(OH)22]n administration can efficiently restore the damaged liver and kidney of the tumor-bearing mice. All the activities of enzymes and other parameters related to oxidative stress were reduced after [Gd@C82(OH)22]n treatment and tended closely to the normal levels. The results suggest that [Gd@C82(OH)22]n nanoparticle treatment could regulate ROS production in vivo.
Animals↗
Acute toxicological effects of copper nanoparticles in vivo.
To assess the toxicity of copper nanoparticles (23.5 nm) in vivo, LD(50), morphological changes, pathological examinations and blood biochemical indexes of experimental mice are studied comparatively with micro-copper particles (17 microm) and cupric ions (CuCl(2).2H(2)O). The LD(50) for the nano-, micro-copper particles and cupric ions exposed to mice via oral gavage are 413, >5000 and 110 mg/kg body weight, respectively. The toxicity classes of nano and ionic copper particles both are class 3 (moderately toxic), and micro-copper is class 5 (practically non-toxic) of Hodge and Sterner Scale. Kidney, liver and spleen are found to be target organs of nano-copper particles. Nanoparticles induce gravely toxicological effects and heavy injuries on kidney, liver and spleen of experimental mice, but micro-copper particles do not, on mass basis. Results indicate a gender dependent feature of nanotoxicity. Several factors such as huge specific surface area, ultrahigh reactivity, exceeding consumption of H(+), etc. that likely cause the grave nanotoxicity observed in vivo are discussed.
Administration, Oral↗
Differential responses of maize MIP genes to salt stress and ABA.
Salt stress is known to reduce root hydraulic conductivity and growth. To examine a concomitant regulation of aquaporins, the expression of the maize MIP gene family in response to NaCl was analysed by DNA array hybridization. Plants responded differentially to 100 versus 200 mM NaCl treatments. Leaf water content was reduced rapidly and persistently after the application of 200 mM NaCl in contrast to 100 mM NaCl. Endogenous ABA strongly accumulated in roots after 2 h; it remained at a highly elevated level for 48 h after the addition of 200 mM NaCl, but rapidly declined in plants treated with 100 mM NaCl, indicating an early recovery from water deficit. Interestingly, 2 h after the addition of 100 mM NaCl, when maize regained the osmotic potential allowing water uptake, three highly expressed, specific isoforms ZmPIP1;1, ZmPIP1;5, and ZmPIP2;4 were transiently induced. They were preferentially transcribed in the outer root tissue suggesting a role in cellular water transport. None of the ZmTIP genes was altered. By contrast, after the addition of 200 mM NaCl these responses were missing. Instead, multiple ZmPIP and ZmTIP genes were repressed by 200 mM NaCl after 24 h. After 48 h, deregulations were overridden in both cases indicating homeostasis. ABA (1 muM) exogenously applied to the roots transiently induced ZmPIP2;4 similar to 100 mM NaCl as well as ZmPIP1;2. Thus, the early induction of ZmPIP2;4 by NaCl may be mediated by ABA. Previously, an increase in root hydraulic conductivity had been observed upon ABA application. By contrast, 100 muM ABA led to a complete, possibly non-specific repression of all detected ZmPIP and ZmTIP genes after 24 h.
Abscisic Acid↗
Characterization of surface property of poly(lactide-co-glycolide) after oxygen plasma treatment.
In this study, poly (lactide-co-glycolide) (PLGA) films were treated by oxygen plasma. The surface structure, topography and surface chemistry of treated PLGA films were characterized by contact angle measurement, scanning electron microscope observation, atomic force microscopy, and X-ray photoelectron spectrum analysis. The cell affinity of the oxygen plasma treated films was evaluated under dynamic conditions by Parallel Plate Flow Chamber (PPFC). The results showed that the hydrophilicity increased greatly after oxygen plasma treatment. High quantities of -C-O groups, such as hydroxyl and peroxyl groups could be incorporated into the surface of PLGA (70/30) by controlling appropriate plasma treatment conditions. Moreover, the oxygen plasma treatment resulted in formation of peaks and valleys on the sample surfaces, and the roughness increased with treatment time. Cells stretched very well and the ability to endure the shear stress was improved greatly after the PLGA (70/30) was modified by appropriate plasma treatment, i.e. under 50W for 2 or 10 min. However, when the treatment time was increased to 20 min, the percentage of adherent cells on the roughest surface decreased because the content of polar groups incorporated onto the surface decreased. The results showed that improved cell adhesion was attributed to the combination of surface chemistry and surface morphology of PLGA during plasma etching.
Animals↗
Specific aptamer-protein interaction studied by atomic force microscopy.
Aptamers are a new class of synthetic DNA/RNA oligonucleotides generated from in vitro selection to selectively bind with various molecules. Due to their molecular recognition capability for proteins, aptamers are becoming promising reagents in protein detection and new drug development. In this study, the specific interaction between the protein immunoglobulin E (IgE) and its 37-nt aptamer has been measured directly by atomic force microscopy. The single-molecule unbinding force between IgE and the aptamer is determined using the Poisson statistical method. The individual unbinding force between IgE and its monoclonal antibody has also been obtained and compared to that between IgE and the aptamer. The results reveal the high affinity of the aptamer to protein, which could match or even surpass that of the antibody to its antigen.
Humans↗