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Modified magnetic starch nanoparticles (FA-StNP@Fe2O3) were synthesized by conjugating folic acid (FA-PEG-NH2) onto the surface of magnetic starch nanoparticles (StNP@Fe2O3) prepared by reverse microemulsion method. The synthesized FA-StNP@Fe2O3 was investigated by transmission electron microscopy and zeta potential analysis. The average size of its well dispersed particles was 250 nm. The iron concentration of 2 mg/g was detected by phenanthroline method. Placing FA-StNP@Fe2O3 nanoparticles in the alternating magnetic field for 30 min resulted in an increase in the suspension temperature from ambient temperature (37°) to a value between 42° and 43°. Co-cultured nanoparticles and Hela cell line or normal HUEC-12 cell line, and the biological effects at the cellular level were investigated in the alternating magnetic field using MTT assay, Hochest-PI double staining and flow cytometry analysis. Experimental results showed that FA-StNP@Fe2O3 within acertain concentration range has no obvious effect on cell proliferation. When treated in the magnetic field, apoptosis rate on Hela induced by FA-StNP@Fe2O3 was 13.4%. Prussian blue staining analysis confirmed that the nanoparticles modified with folic acid had improved ability in tumor cell-targeting, and therefore, potential applications in biomedical and magnetocaloric areas. It is expected be applied in tumor targeting therapy in the near future. [ABSTRACT FROM AUTHOR]

In this work, a novel nano-sized mixed-crystal TiO2 catalyst was obtained under microwave irradiation in hydrogen peroxide solution and its sonocatalytic activity was also investigated through degradation of congo red dye. It was found that the sonocatalytic degradation effect of congo red using nano-sized mixed-crystal TiO2 powder was much higher than that using pure nano-sized rutile phase TiO2 powder. At last, the congo red dyes in aqueous solution were degraded completely and became some simple inorganic ions such as NO, SO and so on. The experiments indicated that the degradation method using such treated nano-sized rutile TiO2 powder as sonocatalyst could be used to treat those non- or low-transparent wastewaters effectively. [ABSTRACT FROM AUTHOR]

We have synthesized Pt@Au and Pt@Cu bimetallic nanoparticles and investigated their surface plasmon resonance (SPR) and plasmon-enhanced photocatalytic activity in the quantum size regime. The SPR wavelength of Pt@Au bimetallic nanoparticles monotonously blue-shifts as the thickness of Pt shell increases comparing with the quantum-sized Au core nanoparticles with diameter dAu = 3.6 ± 0.4 nm. On the other hand, the SPR of Pt@Cu bimetallic nanoparticles blue-shifts at first and then red-shifts as the Pt shell thickness increases comparing to the quantum-sized Cu core nanoparticles with diameter dCu = 3.7 ± 0.5 nm. Then, we comparatively investigated the photocatalytic activities of the Pt@Au nanoparticles with quantum and classical sizes. The photocatalytic rate for 4-NP:NaBH4 is enhanced 2 times by the strong plasmon resonance and the large surface area/volume ratio of quantum-sized Pt@Au nanoparticles. Additionally, the increasing photocatalytic activity of the quantum-sized Pt@Cu with the increase of Pt shell thickness is also observed. These findings reveal the significance of the quantum plasmon resonance on the enhancement of photocatalytic activity. [ABSTRACT FROM AUTHOR]