Sol–Gel Synthesis, Physico-Chemical and Biological Characterization of Cerium Oxide/Polyallylamine Nanoparticles

Abstract

<jats:p>Cerium oxide nanoparticles (CeO2-NPs) have great applications in different industries, including nanomedicine. However, some studies report CeO2-NPs-related toxicity issues that limit their usage and efficiency. In this study, the sol–gel method was applied to the synthesis of CeO2-NPs using poly(allylamine) (PAA) as a capping and/or stabilizing agent. The different molecular weights of PAA (15,000, 17,000, and 65,000 g/mol) were used to investigate the physico-chemical and biological properties of the NPs. In order to understand their performance as an anticancer agent, three cell lines (MCF7, HeLa, and erythrocyte) were analyzed by MTT assay and RBC hemolysis assay. The results showed that the CeO2-NPs had anticancer effects on the viability of MCF7 cells with half-maximal inhibitory concentration (IC50) values of 17.44 ± 7.32, 6.17 ± 1.68, and 0.12 ± 0.03 μg/mL for PAA15000, PAA17000, PAA65000, respectively. As for HeLa cells, IC50 values reduced considerably to 8.09 ± 1.55, 2.11 ± 0.33, and 0.20 ± 0.01 μg/mL, in order. A decrease in the viability of cancer cells was associated with the 50% hemolytic concentration (HC50) of 0.022 ± 0.001 mg/mL for PAA15000, 3.74 ± 0.58 mg/mL for PAA17000, and 7.35 ± 1.32 mg/mL for PAA65000. Ultraviolet-Visible (UV-vis) spectroscopy indicated that an increase in the PAA molecular weight led to a blue shift in the bandgap and high amounts of Ce3+ on the surface of the nanoceria. Thus, PAA65000 could be considered as a biocompatible nanoengineered biomaterial for potential applications in cancer nanomedicine.</jats:p>

Performance evaluation of Nannochloropsis oculate–carbon nanoparticle blend as fuel in compression ignition engine

“…As the engine load increases, HC emissions also increase owing to the availability of more fuel burning inside the chamber. Figure 11 shows an average of 1.22% (BC‐50), 2.07% (BC‐75), 3.88% (BC‐100) and 2.72% (BC‐150) lower HC emissions than that of the diesel at 100% load condition, which justifies the results of previous studies 1,5,12 . This is due to the high cetane rating of the engine as well as the abundance of oxygen, which result in incomplete combustion of the fuel.…”

“…Figure 11 shows an average of 1.22% (BC-50), 2.07% (BC-75), 3.88% (BC-100) 2.72% (BC-150) lower HC emissions than that of the diesel at 100% load condition, which justifies the results of previous studies. 1,5,12 This is due to the high cetane rating of the engine as well as the abundance of oxygen, which result in incomplete combustion of the fuel. In addition, fuel accumulation in the combustion chamber and longer ignition delays can also increase the volume of HC released during combustion.…”

“…Several additives have been used as catalysts, such as CeO 2 , Al 2 O 3 and CuO, to bring about low emissions, high performance and good combustion characteristics. [12][13][14] Carbon nanotubes (CNTs) are an additive used in biofuel and other composite materials. They can act as a promising nano-additives for biodiesel which help to improve the combustion rate of the fuel, the cetane number, act as an anti-knocking agent and enhance clean burning.…”

“…One of the promising approaches that helps to improve microalgae biodiesel fuel quality in terms of low emissions, high performance and good combustion quality is to use a good fuel additive. Several additives have been used as catalysts, such as CeO 2 , Al 2 O 3 and CuO, to bring about low emissions, high performance and good combustion characteristics 12–14 …”

Emerging Role of Redox-Active Nanoceria in Cancer Therapeutics via Oxidative Stress

“…Since cancer cells have higher acidic intracellular environment due to increased rate of lactic acid production and glycolysis, nanoceria can act as pro-oxidant and shows remarkable cytotoxic effect toward cancer cells (Thakur et al 2019). Moreover, functionalization (with specific targeting agents), surface coating, or doping of CeO 2 NPs further enhances its stability, solubility, cellular uptake, and targeting ability to selectively kill cancer cells without damaging normal cells (Babu Varukattu et al 2019;Hosseini et al 2020;Rahdar et al 2019). In addition to its inherent anticancer nature, nanoceria has also been used as a potential drug delivery vehicle for effective and targeted delivery of anticancer drugs for synergistic acticancer activity Damle et al 2020).…”