Saraf Shashank, Neal Craig J, Das Soumen, Barkam Swetha, McCormack Rameech, Seal Sudipta
Advanced Materials Processing and Analysis Center (AMPAC), Materials Science Engineering (MSE), University of Central Florida , 4000 Central Florida Boulevard, Orlando, Florida 32816, United States.
ACS Appl Mater Interfaces. 2014 Apr 23;6(8):5472-82. doi: 10.1021/am405250g. Epub 2014 Apr 14.
The application of cerium oxide nanoparticles (CNPs) for therapeutic purposes requires a stable dispersion of nanoparticles in a biological environment. The objective of this study is to tailor the properties of polyelectrolyte coated CNPs as a function of molecular weight to achieve a stable and catalytic active dispersion. The coating of CNPs with polyacrylic acid (PAA) has increased the dispersion stability of CNPs and enhanced the catalytic ability. The stability of PAA coating was analyzed using the change in the Gibbs free energy computed by the Langmuir adsorption model. The adsorption isotherms were determined using soft particle electrokinetics which overcomes the challenges presented by other techniques. The change in Gibbs free energy was highest for CNPs coated with PAA of 250 kg/mol indicating the most stable coating. The change in free energy for PAA of 100 kg/mol coated CNPs was 85% lower than the PAA of 250 kg/mol coated CNPs. This significant difference is caused by the strong adsorption of PAA of 100 kg/mol on CNPs. Catalytic activity of PAA-CNPs is assessed by the catalase enzymatic mimetic activity of nanoparticles. The catalase activity was higher for PAA coated CNPs as compared to bare CNPs which indicated preferential adsorption of hydrogen peroxide induced by coating. This indicates that the catalase activity is also affected by the structure of the coating layer.
将氧化铈纳米颗粒（CNPs）用于治疗目的需要纳米颗粒在生物环境中稳定分散。本研究的目的是根据分子量来调整聚电解质包覆的CNPs的性质，以实现稳定且具有催化活性的分散体。用聚丙烯酸（PAA）包覆CNPs提高了CNPs的分散稳定性并增强了催化能力。使用由朗缪尔吸附模型计算的吉布斯自由能变化来分析PAA包覆的稳定性。吸附等温线通过软颗粒电动学来测定，该方法克服了其他技术所带来的挑战。对于包覆有250 kg/mol PAA的CNPs，吉布斯自由能变化最大，表明包覆最稳定。包覆有100 kg/mol PAA的CNPs的自由能变化比包覆有250 kg/mol PAA的CNPs低85%。这种显著差异是由100 kg/mol的PAA在CNPs上的强吸附引起的。通过纳米颗粒的过氧化氢酶模拟活性来评估PAA-CNPs的催化活性。与未包覆的CNPs相比，包覆PAA的CNPs的过氧化氢酶活性更高，这表明包覆诱导了过氧化氢的优先吸附。这表明过氧化氢酶活性也受包覆层结构的影响。
