Manganese dioxide nanosheet-containing reactors as antioxidant support for neuroblastoma cells.

Supporting mammalian cells against reactive oxygen species such as hydrogen peroxide (H2O2) is essential. Bottom-up synthetic biology aims to integrate designed artificial units with mammalian cells. Here, we used manganese dioxide nanosheets (MnO2-NSs) as catalytically active entities that have superoxide dismutase-like and catalase-like activities. The integration of these MnO2-NSs into 7 µm reactors was able to assist SH-SY5Y neuroblastoma cells when stressed with H2O2. Complementary, Janus-shaped 800 nm reactors with one hemisphere coated with MnO2-NSs showed directed locomotion in cell media with top speeds up to 50 µm s-1 when exposed to 300 mM H2O2 as a fuel, while reactors homogeneously coated with MnO2-NSs were not able to outperform Brownian motion. These Janus-shaped reactors were able to remove H2O2 from the media, protecting cells cultured in the proximity. This effort advanced the use of bottom-up synthetic biology concepts in neuroscience.

Food-Borne Nanocarriers for Calcium Delivery: A New Choice for Nutrient Supplements.

Calcium is considered as an important nutrient element for the maintenance of human health, and food-borne nanoparticles (FNs) produced during food processing may have potential as nanocarriers for calcium ion delivery. Beef is an important source of animal protein that has high protein and low fat content and is rich in a variety of amino acids; thus, beef may be a suitable material for the development of calcium nanocarriers. In this paper, FNs were synthesized from beef by one-step hydrothermal synthesis. The FNs had a spherical shape with a size of about 3.0 nm and emitted a bright blue fluorescence under 365 nm ultraviolet irradiation. The amino nitrogen atom and carboxyl oxygen atom of the functional groups on the surface of the FNs were the main binding sites for the chelation of Ca(II). The size of the FNs-Ca(II) complex was about 4.75 nm, and the specific signal peak of calcium at 3.7 keV was observed in its energy dispersive X-ray spectroscopy spectrum. The viability of cells treated with FNs-Ca(II) was more than 65%, while viability was only 60% after treatment with CaCl2. The results showed that the FNs from beef have great potential in calcium delivery for the development of a calcium supplement.

Fluorescence nanoparticles from instant coffee accumulated in lysosome and induced lysosome-dependent cell death via necroptosis-like pathway.

Fluorescence nanoparticles (FNs) are a type of nano-dots generated during baking process, and their safety on organism is unclear and little is known to their cytotoxicity. In this study, the FNs from instant coffee were purified and characterized. The FNs with an average size about 2.08 nm emitted bright blue fluorescence with lifetime about 2.74 ns. The element and functional groups were analyzed by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy, respectively. The results indicated that these FNs were internalized in lysosomes and induced apoptosis of normal rat kidney (NRK) and Caco-2 cells. While, the pan-caspase inhibitor, Z-VAD-FMK didn't decrease the rate of apoptosis and cell death of the FNs-treated NRK and Caco-2 cells. These internalized FNs enlarged lysosomes, decreased lysosomal enzyme degradation activity and increased lysosomal pH value. Partial co-localization of receptor-interacting serine-threonine kinase 3 (RIPK3) to lysosomes in FNs-treated cells was observed, and the amount of RIPK1 and RIPK3 increased after treatment with FNs. The results demonstrated that the FNs from instant coffee induced lysosomal membrane permeabilization and initiated necroptosis.

Food-borne nanocarriers from roast beef patties for iron delivery.

Food-borne nanoparticles (FNs) produced during thermal processing of food may have potential as nanocarriers for Fe(ii) supplements. In this paper, the FNs in beef patties roasted for different times (15, 30, and 45 minutes) and the binding between FNs and ferrous ions were studied. The size of FNs decreased from 7.5 to 3.0 nm with the increase of baking time, and the FNs emitted bright blue fluorescence under ultraviolet light irradiation. The combination of FNs with ferrous ions was by means of the amino, hydroxyl and carboxyl functional groups on the particles. Cell viability study showed that the Fe(ii)-FNs increased the apoptotic rate, but significantly decreased the necrosis rate, which led to an increase in the number of living cells. In addition, the Fe(ii)-FNs can easily enter the Caco-2 cytoplasm, but not the cellular nucleus. The FNs derived from beef patties with an ultra-small size, high water solubility and plenty of functional groups might be good candidates as nanocarriers for Fe(ii) delivery.

Fluorescent nanoparticles in the popular pizza: properties, biodistribution and cytotoxicity.

Food-borne nanoparticles that are generated during the thermal processing of various consumed foods are of great concern due to their unique properties. In this study, the presence of fluorescent nanoparticles (FNPs) in pizza, their biodistribution and cytotoxicity were investigated. The spherical FNPs have a diameter of about 3.33 nm. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analysis revealed that they contained 68.21% C, 27.44% O, 2.75% N and 1.60% S, and the functional groups on their surface included -OH, -COOH, C[double bond, length as m-dash]C, -NH2 and C[double bond, length as m-dash]O. In vitro and in vivo biodistribution of pizza FNPs was evaluated using normal rat kidney (NRK) cells, onion epidermal cells, Caenorhabditis elegans and mice. The fluorescence microscopy images clearly indicate that the pizza FNPs appear to be localized within the cytoplasm. However, the FNPs remained restricted to the extracellular space of the onion epithelium and did not enter the onion cell cytoplasm because of the cell wall. The FNPs were swallowed by the Caenorhabditis elegans worms when exposed to food OP50 and distributed within the pharynx, intestine and anus. Obvious fluorescence of the FNPs in the stomach, intestine, liver, lung and kidney was observed for the FNPs in mouse organs, but not the brain, heart, and spleen. Furthermore, the produced FNPs were found to cause cell cycle arrest at the G0/G1 phase in NRK cells, and resulted in cell apoptosis at high doses. The outcome of this research offers an important insight into the nature of thermal processing-induced nanoparticles and their in vivo and in vitro biological effects.