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Background:The objective of this study was to evaluate the synthesis and biocompatibility of Fe 3 O 4 nanoparticles and investigate their therapeutic effects when combined with magnetic fluid hyperthermia on cultured MCF-7 cancer cells. Methods: Magnetic Fe 3 O 4 nanoparticles were prepared using a coprecipitation method. The appearance, structure, phase composition, functional groups, surface charge, magnetic susceptibility, and release in vitro were characterized by transmission electron microscopy, x-ray diffraction, scanning electron microscopy-energy dispersive x-ray spectroscopy, and a vibrating sample magnetometer. Blood toxicity, in vitro toxicity, and genotoxicity were investigated. Therapeutic effects were evaluated by MTT [3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium bromide] and flow cytometry assays. Results: Transmission electron microscopy revealed that the shapes of the Fe 3 O 4 nanoparticles were approximately spherical, with diameters of about 26.1 ± 5.2 nm. Only the spinel phase was indicated in a comparison of the x-ray diffraction data with Joint Corporation of Powder Diffraction Standards (JCPDS) X-ray powder diffraction files. The O-to-Fe ratio of the Fe 3 O 4 was determined by scanning electron microscopy-energy dispersive x-ray spectroscopy elemental analysis, and approximated pure Fe 3 O 4 . The vibrating sample magnetometer hysteresis loop suggested that the Fe 3 O 4 nanoparticles were superparamagnetic at room temperature. MTT experiments showed that the toxicity of the material in mouse fibroblast (L-929) cell lines was between Grade 0 to Grade 1, and that the material lacked hemolysis activity. The acute toxicity (LD 50 ) was 8.39 g/kg. Micronucleus testing showed no genotoxic effects. Pathomorphology and blood biochemistry testing demonstrated that the Fe 3 O 4 nanoparticles had no effect on the main organs and blood biochemistry in a rabbit model. MTT and flow cytometry assays revealed that Fe 3 O 4 nano magnetofluid thermotherapy inhibited MCF-7 cell proliferation, and its inhibitory effect was dose-dependent according to the Fe 3 O 4 nano magnetofluid concentration. Conclusion: The Fe 3 O 4 nanoparticles prepared in this study have good biocompatibility and are suitable for further application in tumor hyperthermia.

Highlights d The immunity against RNA viruses severely inhibits the catalytic activity of OTUD3 d Loss of OTUD3 elevates innate antiviral immune response d OTUD3 directly hydrolyzed Lys63 polyubiquitination on MAVS d Lys129 acetylation increases OTUD3 activity to Lys63-Ub; SIRT1 removes Lys129 acetylation

Aromatic−aromatic interactions between natural aromatic amino acids Phe, Tyr, and Trp play crucial roles in protein−protein recognition and protein folding. However, the function of such interactions in the preparation of different dimensional, ordered protein superstructures has not been recognized. Herein, by a combination of the directionality of the symmetry axes of protein building blocks and the strength of the aromatic− aromatic interactions coming from a group of aromatic amino acid residues, we built an engineering strategy to construct protein superlattices. Based on this strategy, substitution of single amino acid residue Glu162 around the C 4 rotation axes near the outer surface of 24-mer ferritin nanocage with Phe, Tyr, and Trp, respectively, resulted in 2D and 3D protein superlattices where protein cages are aligned along the C 4 axes, imposing a fixed disposition of neighboring ferritins. The self-assembly of these superlattices is reversible, which can be tuned by external stimuli (salt concentration or pH). Moreover, these superlattices can serve as biotemplates for the fabrication of 2D and 3D inorganic nanoparticle arrays.

Ferritin is a class of naturally occurring iron storage proteins, which is distributed widely in animal, plant, and bacteria. It usually consists of 24 subunits that form a hollow protein shell with high symmetry. One holoferritin molecule can store up to 4500 iron atom within its inner cavity, and it becomes apoferritin upon removal of iron from the cavity. Recently, scientists have subverted these nature functions and used reversibly self-assembled property of apoferritin cage controlled by pH for the encapsulation and delivery of bioactive nutrients or anticancer drug. In all these cases, the ferritin cages shield their cargo from the influence of external conditions and provide a controlled microenvironment. More importantly, upon encapsulation, ferritin shell greatly improved the water solubility, thermal stability, photostability, and cellular uptake activity of these small bioactive compounds. This review aims to highlight recent advances in applications of ferritin cage as a novel vehicle in the field of food science and nutrition. Future outlooks are highlighted with the aim to suggest a research line to follow for further studies.