Magnetic targeted drugs delivery system (MTDDS) is a new targeted drug system, which can greatly reduce the dosage and improve the therapeutic efficiency of medicine. Currently superparamagnetic ferric oxide plays important function as targeted drug in the treatment of tumors, but cytotoxicity was still regarded as side effect in the process of drug. In this paper, we take advantage of drug carrier (ferric oxide) toxicity controlling cancer cell growth in cancer treatment, increasing targeted drug efficiency. We applied the modified chemical precipitation method to prepare polylactic acid (PLA) coated high-purity superparamagnetic Fe 3 O 4 nanoparticles for targeted drug, characterized PLA/Fe 3 O 4 microspheres physical and chemical properties, and then investigated cytotoxicity influence of PLA/Fe 3 O 4 nanomagnetic microspheres as carrier for normal liver cells (7701) and liver cancer cells (HePG2) in different concentration; results of MTT and hemolysis and micronucleus test showed that carrier restrained the growth of HePG2 in special concentration, meanwhile the proliferation rate of liver cells was not affected. The study demonstrates that compared with liver cell, liver cancer cells (HepG2) are easy to be disturbed by PLA/Fe 3 O 4 nanomagnetic microsphere, which have higher sensitivity and absorption ability. We hope to take advantage of the susceptible property of cancer cells for carriers to improve targeted drug function.
Ceria nanoparticles were classified as nanozymes because they are able to mimic the activities of some natural enzymes such as superoxide dismutase (SOD), catalase, oxidase and photolyase under given conditions. These functions have driven studies to explore the factors that could promote ceria nanoparticle enzyme activities. Accordingly, factors including size, shape, exposed plane and surface coating that could modulate the enzymatic activities of ceria nanoparticles have been explored. In the present study, we investigated the relationship between ceria nanoparticle crystallinity and SOD-like activity. Two groups of ceria nanoparticles with sizes of several nanometers and tens of nanometers in each group were synthesized with different crystallinities. The ceria nanoparticle crystallinities were closely connected to their Ce 3 + /Ce 4 + ratio, where the lower crystallinity resulted in a higher Ce 3 + concentration and vice versa. The catalytic activity evaluation results indicated that the nanoparticles featuring lower crystallinity exhibited higher SOD-like activity even though the nanoparticles had a smaller specific surface area. The crystallinity-dominated SOD-like activity variation could be sensed by cells, as the nanoparticles featuring lower crystallinity could better protect the cells from paraquat-induced oxidative stress. Therefore, decreasing crystallinity could be an effective way to achieve highly active ceria nanoparticles for SOD-related biological applications.
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