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Cerium oxide-based nanozymes have recently drawn much attention in the field of biomedical and antioxidant applications, because of their unique regenerative or autocatalytic properties. Herein, we studied the biomimetic superoxide dismutase (SOD) nanozymes CeO2-Gd that combines the fluorescence properties of rare earth Gd with the antioxidant properties of CeO2 nanoparticles, which was prepared via facile route. The structure and composition of the CeO2-Gd were measured and verified by X-ray powder diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray electron spectroscopy (XPS). Confocal microscopy was used to image cells. Antioxidant performance and cell viability of these nanozymes were measured in vitro using BGC-803 cell. CeO2-Gd nanozymes with a higher Ce3+/Ce4+ ratio show higher superoxide dismutase (SOD) mimetic activity. Their antioxidant activity and fluorescence properties of CeO2-Gd in BGC-803 cancer cells are enhanced by oxygen vacancies generated by doping rare-earth elements Gd. This work may guide the future design of CeO2-Gd-based biomimetic nanozymes for anticancer and antioxidant applications.

Selective deconstructive functionalization of alkenes, other than the well-established olefin metathesis and ozonolysis, to produce densely functionalized molecular scaffolds is highly attractive but challenging. Here we report an efficient photo-mediated deconstructive germinal dihalogenation of carbon-carbon double bonds. A wide range of geminal diiodoalkanes and bromo(iodo)alkanes (>40 examples) are directly prepared from various trisubstituted alkenes, including both cyclic and acyclic olefins. This C=C cleavage is highly chemoselective and produces geminal dihalide ketones in good yields. Mechanistic investigations suggest a formation of alkyl hypoiodites from benzyl alcohols and N-iodoimides, which undergo light-induced homolytic cleavage to generate active oxygen radical species., Efficient synthetic pathways to geminal dihalides are quite limited, despite their versatility as chemical building blocks. Here, the authors report a photo-mediated deconstructive fragmentation of cyclic and acyclic trisubstituted alkenes to access a variety of geminal dihalides.

A visible-light-mediated radical Smiles rearrangement has been achieved using neutral eosin Y as a direct hydrogen atom transfer (HAT) photocatalyst. Novel N-heterocycles as single diastereomers fe...

Robotic micro/nanoswimmers can potentially be used as tools for medical applications, such as drug delivery and noninvasive surgery. Recently, achiral microswimmers have gained significant attention because of their simple structures, which enables high-throughput fabrication and size scalability. Here, microparticle image velocimetry (&micro, PIV) was used to study the hydrodynamics of achiral microswimmers near a boundary. The structures of these microswimmers resemble the letter L and were fabricated using photolithography and thin-film deposition. Through &micro, PIV measurements, the velocity flow fields of the microswimmers rotating at different frequencies were observed. The results herein yield an understanding of the hydrodynamics of the L-shaped microswimmers, which will be useful in applications such as fluidic manipulation.

CeO2 nanoparticles (Ce NPs) have received considerable interest due to their unique autocatalytic property. In this paper, the autocatalytic properties of Ce NPs of three different sizes were measured in vitro using a human gastric cancer cell line (BGC-803) at different concentrations ranging from 20 ng μL−1 to 200 ng μL−1. The evaluation model of the autocatalytic properties of the Ce NPs was built by partial least squares regression (PLSR) based on the Matlab software. Multiple variable factors were quantitatively analyzed in terms of regression and correlation. The model indicated that the concentration was the primary factor, followed by the size of the Ce NPs. The autocatalytic properties of the Ce NPs was also promoted by the specific surface area, the valence states of Ce, and the surface charge in the cell culture medium. This study attempted to establish a quantitative framework and supply a new strategy for evaluating the autocatalytic property of cerium oxide nanoparticles for their use in biological and medical fields.

Enantioenriched 1,4-dicarbonyl compounds are versatile synthons in natural product and pharmaceutical drug synthesis. We herein report a mild pathway for the efficient enantioselective synthesis of these compounds directly from aldehydes through synergistic cooperation between a neutral eosin Y hydrogen atom transfer photocatalyst and a chiral rhodium Lewis acid catalyst. This method is distinguished by its operational simplicity, abundant feedstocks, atom economy, and ability to generate products in high yields (up to 99 %) and high enantioselectivity (up to 99 % ee).

A mild in situ method was developed to construct an iron doped rutile TiO2 photocatalyst like cauliflower for degradation synthetic textile dye-methyl orange. The synthesized photocatalysts presented distinguished photocatalytic activity. At the optimal Fe concentration (0.5%), the decomposition rate of methyl orange (MO) was about 90% under 40 min of ultraviolet (UV) light irradiation. Whereas, to our knowledge, only 70% of the decomposition rate of MO was achieved by commercial photocatalyst P25 under the similar reaction condition. Additionally, the rutile preparation temperature did not exceed 100 &deg, C, which was much lower than the traditional preparation calcination temperature (e.g., 600 &deg, C). The specific surface area of Fe doped catalysts was bigger than that of the control sample and the catalyst characterization indicated that the doped iron was incorporated into the rutile TiO2 lattice and resulted in the lattice disorder. The lattice disorder would have generated surface defects in the crystal structure, which was in favor of the photocatalytic reaction. The UV-Vis diffuse refection characterization and Density Functional Theory (DFT) calculation suggested that doping a small amount of Fe into the lattice of rutile would lead to a narrower band gap and the formation of a doping energy level between conduction and valence bands of TiO2. This further increased the degradation efficiency of synthetic textile dyes in wastewaters. Our study has provided a relatively easy operation for synthesis Fe doped rutile TiO2, which is a benefit to decrease the cost in wastewater treatment process.

As a new antioxidant, nanoceria is of significant importance in applications of medical and biological fields. In comparison with conventional organic antioxidants, nanoceria has multienzyme mimetic activity by Ce4+/Ce3+ redox cycle. This unique regenerative/autocatalytic property has been widely used in the aspects of free-radical scavenger, radiation protection, oxidative-stress-related disease, drug delivery, biosensor, tissue engineering, cancer biomarker, and anti-inflammatory. This paper reviews the latest breakthrough of nanoceria as an antioxidant in applications of medical and biological fields on the base of the authors’ research works on resistance to oxidation and cytotoxicity. The challenges of nanoceria encountered in applications in medical and biological fields are commented as well.