SGER: Surface Chemistry in metal oxide nanoparticle cytotoxicity

Sudipta SealUniversity Central florida纳米技术的快速发展导致了大量纳米颗粒（NPs）的出现，这些纳米颗粒在大小、电荷、化学性质和溶解度方面各不相同。特别是无机纳米颗粒，被证明在清除氧自由基方面是有效的，氧自由基可以引起许多临床疾病，如活生物体的细胞功能障碍。一些NPs被证明是有毒的，可以产生有害的自由基。我们的研究表明，稀土NPs的有益治疗特性被认为是无毒的。氧化铈NPs清除自由基的独特性质是由于它们能够在+3和+4状态之间进行可逆的氧化还原反应，从而将自由基清除成无害的副产物，模仿天然酶的性质。此外，我们还发现掺杂可以增加氧空位的数量，从而可能提高自由基清除性能。最近，我们报道了微摩尔浓度的氧化铈NPs（自然纳米技术，2006）在防止大鼠视网膜原代细胞培养中活性氧引起的感光细胞损伤方面的有效性。但是，为了获得最佳的治疗效果，仍需要全面了解具有生物活性的NP表面特性。具体目标：与其他金属氧化物和抗氧化剂相比，稀土金属氧化物NPs具有优越的自由基清除性能，并且无毒。Ce3+和Ce4+在工程NPs中的共存在其抗氧化行为中起着关键作用，并使其成为一种活性自由基清除剂。目前还不清楚NP的大小、表面电荷、团聚、掺杂性质和浓度如何影响NPs在体内的活性。目前的项目将解决这些重要问题，主要目标是：(i)合成NPs并表征其大小和表面特性，（ii）研究zeta电位对细胞摄取的影响，（iii）确定皮肤和肺培养模型中NPs的细胞毒性，（iv）利用细胞培养评估NPs诱导的氧化应激。

Sudipta SealUniversity Central FloridaCBET-0711239SGER: Surface Chemistry in Metal Oxide Nanoparticle CytoxicityThe rapid expansion of nanotechnology has resulted in a vast array of nanoparticles (NPs) that vary in size, charge, chemistry and solubility. Inorganic nanoparticles, in particular, are shown to be effective in scavenging oxygen free radicals which can cause many clinical diseases such as cellular dysfunction in living organisms. Some of the NPs are shown to be toxic and can generate harmful free radicals. Our research has shown the beneficial therapeutic properties of rare earth NPs which are considered to be non-toxic. The unique property of ceria NPs in radical scavenging is due to their ability to undergo reversible redox reaction between the +3 and +4 states, thereby scavenging the free radicals into harmless by-products, mimicking the properties of natural enzyme. Further we have shown that doping can increase number of oxygen vacancies which is likely to improve the free radical scavenging properties. Recently we have reported the effectiveness of micromolar concentrations of ceria NPs (Nature Nanotechnology, 2006) in preventing the photoreceptor cell damage due to reactive oxygen species in the primary cell cultures of rat retina. But still a comprehensive understanding on NP surface properties with biological activity is required for optimum therapeutic properties.Specific objectives: In comparison to other metal oxides and anti-oxidants, rare earth metal oxide NPs exhibit superior free radical scavenging properties and are non toxic. The co-existence of both Ce3+ and Ce4+ in the engineered NPs plays a critical role in its antioxidant behavior and enables it to be an active free radical scavenger. It is also not known how NP size, surface charges, agglomeration, dopant nature and concentration govern the activity of the NPs in vivo. Present project will address these important issues and the main objectives are: (i) to synthesis of NPs and characterizing size and surface properties, (ii) to study the influence of zeta potential on the cellular uptake, (iii) to determine the cytotoxicity of NPs in skin and lung culture models, (iv) to assess the oxidative stress induced by NPs using cell cultures.