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Investigation Of Cytotoxicity Of Several Colloidal Particles And Systems To Suppress Their Cytotoxicity

Posted on:2016-03-18Degree:DoctorType:Dissertation
Country:ChinaCandidate:W J ZhangFull Text:PDF
GTID:1221330485978248Subject:Polymer Chemistry and Physics
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Recently, the colloidal particles which including nanoparticles have received extensive attention along with the development of nanotechnology and application of nanomaterials. During the application, the adverse effects of colloidal particles on human being and environment have been received more attention. Wherein toxicity evaluation of the colloidal particles is particularly important, toxic reduction or elimination of colloidal particles has become one of the necessary research. In this thesis, the impact of volume expand of stimuli-response carriers on cell viability is investigated. Attention is paid to the cytotoxicity and genotoxicity of four kinds of CuO nanoparticles with different surface chemistry, as well as the influence on the differentiation potential of rat mesenchymal stem cells. Toxicity reduction and abatement action of CuO nanoparticles and air pollutants PM2.5 water extract against reactive oxidative stress by inhibiting molecules are investigated.The physical chemical properties of stimuli-response material will have certain changes in response to environmental stimuli in the application process of stimuli-response material. For example, thermo-responsive PNIPAM has volume phase transition in response to temperature change, so it is important to evaluate the biosafety of stimuli-response carrier which may swell inside of cell. The PNIPAM microgel particles with a volume phase transition were prepared by precipitation polymerization of NIPAM, poly(ethylene glycol) diacrylate and acrylic acid. PNIPAM was modified with cell penetrating peptide (TAT) in order to increase cellular uptake. The results show that TAT modification could increase cellular uptake but had no significant influence on intracellular distribution. After internalized into A549 cells, the PNIPAM microgel particles did not show significant impact on cell viability at 37 ℃, but they caused cytotoxicity to some extent when being cultured at 25℃ for 4 h. Doxorubicin-loaded PNIPAM microgel particles showed the strongest cytotoxicity when being cultured at 25℃ for 4 h, suggesting the combinational effect of intracellular volume expansion and drug release on cells.The influence of four kinds of CuO nanoparticles with different surface chemistry, i.e naked (CuO-core), polymer with amino group modified (CuO-NHb), polymer with carboxyl group modified (CuO-COOH), poly(ethylene glycol) derivative polymer modified (CuO-PEG)) on rat mesenchymal stem cells was studied in vitro. All of the four types of CuO NPs had a negative surface charge around-10 mV and showed a similar tendency to form agglomerates with a size of ~200 nm in cell culture environment. The cytotoxicity of CuO NPs to MSCs at various concentrations and incubation periods was firstly evaluated. The CuO NPs showed dose-dependent and time-dependent toxicity to MSCs, and their surface chemistry had influence on the toxicity to some extent too. The intracellular reactive oxygen species (ROS) level of MSCs was then quantified. Finally, the genotoxicity of the CuO NPs was studied by comet assay. The results suggest that the genotoxicity of CuO NPs was mainly dependent on NPs concentration, and was only slightly influenced by their surface chemistry. The osteogenic and adipogenic differentiation ability of MSCs influenced by copper oxide nanoparticles was studied by Alizarin Res S and Oil Red O staining after being co-cultured with CuO NPs. The results show that co-culture with 10 ug/mL CuO NPs has no significant influence on MSCs differentiation potential.It is known that the nanoparticles toxicity is usually correlated with the generation of reactive oxygen species (ROS) which can induce oxidative damage, cytotoxicity and genotoxicity. Antioxidant drug curcumin (CUR)-loaded bovine serum albumin (BSA) microparticles (CUR/BSA) were prepared by co-precipitation of CUR with BSA, and their inhibition effect on CuO nanoparticles toxicity was then investigated. The CUR/BSA microparticles had higher intracellular accumulation and low cytotoxicity in both A549 and RAW264.7 cells compared with free curcumin at the same curcumin concentration. They could supress the cytotoxicity of CuO nanoparticles to A549 and RAW264.7 cell after co-culture for 6 h as a result of decrease of the intracellular ROS level caused by CuO nanoparticles and intracellular copper ion concentration.Further more, the thermo-responsive PNIPAM was used to prepare antioxidant molecule melatonin (MLT) lodaded MLT-PNIPAM microgel particles. The MLT release from MLT-PNIPAM in response to temperature and toxicity reduction and abatement action of air pollutants PM2.5 water extract were investigated. MLT-PNIPAM microgel particles had higher MLT release at 25℃ than at 37℃. MLT-PNIPAM could reduce the cytotoxcity of PM2.5 water extract. MLT-PNIPAM microgel particles suppressed the cytotoxicity of PM2.5 water extract by reducing intracellular ROS level, too.
Keywords/Search Tags:toxicity, toxicity inhibition, PNIPAM, thermo-responsive, antioxidant, oxidative stress, CuO particles
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