Lipid Production,Oxidative Status,Antioxidant Enzymes and Photosynthetic Efficiency of Coccomyxa chodatii SAG 216-2 in Response to Calcium Oxide Nanoparticles

The extensive use of nanoparticles(NPs)in diverse applications causes their localization to aquatic habitats,affecting the metabolic products of primary producers in aquatic ecosystems,such as algae.Synthesized calcium oxide nanoparticles(CaO NPs)are of the scarcely studied NPs.Thus,the current work proposed that the exposure to CaO NPs may instigate metabolic pathway to be higher than that of normally growing algae,and positively stimulate algal biomass.In this respect,this research was undertaken to study the exposure effect of CaO NPs(0,20,40,60,80,and 100μg mL^(−1))on the growth,photosynthesis,respiration,oxidative stress,antioxidants,and lipid production of the microalga Coccomyxa chodatii SAG 216-2.The results showed that the algal growth concomitant with chlorophyll content,photosynthesis,and calcium content increased in response to CaO NPs.The contents of biomolecules such as proteins,amino acids,and carbohydrates were also promoted by CaO NPs with variant degrees.Furthermore,lipid production was enhanced by the applied nanoparticles.CaO NPs induced the accumulation of hydrogen peroxide,while lipid peroxidation was reduced,revealing no oxidative behavior of the applied nanoparticles on alga.Also,CaO NPs have a triggering effect on the antioxidant enzymes such as superoxide dismutase,catalase,ascorbate peroxidase,and guaiacol peroxidase.The results recommended the importance of the level of 60μg mL^(−1) CaO NPs on lipid production(with increasing percentage of 65%compared to control)and the highest dry matter acquisition of C.chodatii.This study recommended the feasibility of an integrated treatment strategy of CaO NPs in augmenting biomass,metabolic up-regulations,and lipid accumulation in C.chodatii.

Effects of quaternary ammonium chain length on the antibacterial and remineralizing effects of a calcium phosphate nanocomposite

Composites containing nanoparticles of amorphous calcium phosphate （NACP） remineralize tooth lesions and inhibit caries. A recent study synthesized quaternary ammonium methacrylates （QAMs） with chain lengths （CLs） of 3-18 and determined their effects on a bonding agent. This study aimed to incorporate these QAMs into NACP nanocomposites for the first time to simultaneously endow the material with antibacterial and remineralizing capabilities and to investigate the effects of the CL on the mechanical and biofilm properties. Five QAMs were synthesized： DMAPM （CL3）, DMAHM （CL6）, DMADDM （CL12）, DMAHDM （CL16）, and DMAODM （CL18）. Each QAM was incorporated into a composite containing 20% NACP and 50% glass fillers. A dental plaque microcosm biofilm model was used to evaluate the antibacterial activity. The flexural strength and elastic modulus of nanocomposites with QAMs matched those of a commercial control composite （n = 6; P 〉 0.1）. Increasing the CL from 3 to 16 greatly enhanced the antibacterial activity of the NACP nanocomposite （P 〈 0.05）; further increasing the CL to 18 decreased the antibacterial potency. The NACP nanocomposite with a CL of 16 exhibited biofilm metabolic activity and acid production that were 10-fold lesser than those of the control composite. The NACP nanocomposite with a CL of 16 produced 2-log decreases in the colony-forming units （CFU） of total microorganisms, total streptococci, and mutans streptococci. In conclusion, QAMs with CLs of 3-18 were synthesized and incorporated into an NACP nanocomposite for the first time to simultaneously endow the material with antibacterial and remineralization capabilities. Increasing the C/reduced the metabolic activity and acid production of biofilms and caused a 2-log decrease in CFU without compromising the mechanical properties. Nanocomposites exhibiting strong anti-biofilm activity, remineralization effects, and mechanical properties are promising materials for tooth restorations that inhibit caries.

One-year water-ageing of calcium phosphate composite containing nano-silver and quaternary ammonium to inhibit biofilms

Dental composites are commonly used restorative materials; however, secondary caries due to biofilm acids remains a major problem. The objectives of this study were （1） to develop a composite containing quaternary ammonium dimethacrylate （QADM）, nanoparticles of silver （NAg）, and nanoparticles of amorphous calcium phosphate （NACP）, and （2） to conduct the first investigation of the mechanical properties, biofilm response and acid production vs water-ageing time from 1 day to 12 months. A 4 x 5 design was utilized, with four composites （NACP-QADM composite, NACP-NAg composite, NACP-QADM-NAg composite, and a commercial control composite）, and five water-ageing time periods （1 day, and 3, 6, 9, and 12 months）. After each water- ageing period, the mechanical properties of the resins were measured in a three-point flexure, and antibacterial properties were tested via a dental plaque biofilm model using human saliva as an inoculum. After 12 months of water-ageing, NACP-QADM- NAg had a flexural strength and elastic modulus matching those of the commercial control （P〉 0.1）. Incorporation of QADM or NAg into the NACP composite greatly reduced biofilm viability, metabolic activity and acid production. A composite containing both QADM and NAg possessed a stronger antibacterial capability than one with QADM or NAg alone （P〈0.05）. The anti-biofilm activity was maintained after 12 months of water-ageing and showed no significant decrease with increasing time （P〉0.1）. In conclusion, the NACP-QADM-NAg composite decreased biofilm viability and lactic acid production, while matching the load- bearing capability of a commercial composite. There was no decrease in its antibacterial properties after 1 year of water-ageing. The durable antibacterial and mechanical properties indicate that NACP-QADM-NAg composites may be useful in dental restorations to combat caries.

Study on application of CeO_2 and CaCO_3 nanoparticles in lubricating oils

The ceria （CeO2） nanoparticles and calcium carbonate （CaCO3） nanoparticles were chosen as additives of anti-wear and extreme pressure for lubricating oils, and the morphology and sizes of nanoparticles were examined using Transmission Electron Microscope （TEM）. The tribological performance of lubricating oils containing combined nanoparticles were determined by four-ball friction and wear tester, and the chemical composition of steel ball with worn surface were analyzed by X-ray Photoelectron Spectrurn（XPS）. The results showed that the lubricating oils containing combined nanoparticles had good anti-wear and friction reducing effects, and the tribological properties were optimal when WCeO2＋CaCO3=0.6%, WCeO2：WCaCO3=1：1. The extreme pressure value increased by 40.25%, the wear spot diameter reduced by 33.5%, and friction coefficient reduced by 32% compared with 40CD oil. The coordinated action of big and small particles made anti-wear and friction reducing effective. Tribological chemical reactions resulting from the friction surface formed metal calcium, metal cerium and oxides film, and they could fill up the concave surface and protect the worn surface.

Novel rechargeable calcium phosphate nanoparticle-containing orthodontic cement

White spot lesions （WSLs）, due to enamel demineralization, occur frequently in orthodontic treatment. We recently developed a novel rechargeable dental composite containing nanoparticles of amorphous calcium phosphate （NACP） with long-term calcium （Ca） and phosphate （P） ion release and caries-inhibiting capability. The objectives of this study were to develop the first NACP- rechargeable orthodontic cement and investigate the effects of recharge duration and frequency on the efficacy of ion re-release. The rechargeable cement consisted of pyromellitic glycerol dimethacrylate （PMGDM） and ethoxylated bisphenol A dimethacrylate （EBPADMA）. NACP was mixed into the resin at 40% by mass. Specimens were tested for orthodontic bracket shear bond strength （SBS） to enamel, Ca and P ion initial release, recharge and re-release. The new orthodontic cement exhibited an SBS similar to commercial orthodontic cement without CaP release （P〉 0.1）. Specimens after one recharge treatment （e.g., 1 min immersion in recharge solution repeating three times in one day, referred to as ＂1 min 3 times＂） exhibited a substantial and continuous re-release of Ca and P ions for 14 days without further recharge. The ion re-release did not decrease with increasing the number of recharge/re-release cycles （P〉 0.1）. The ion re-release concentrations at 14 days versus various recharge treatments were as follows： 1 min 3 times〉3 min 2 times〉 1 min 2 times〉6 min 1 time〉3 min 1 time〉 1 min 1 time. In conclusion, although previous studies have shown that NACP nanocomposite remineralized tooth lesions and inhibited caries, the present study developed the first orthodontic cement with Ca and P ion recharge and long-term release capability. This NACP-rechargeable orthodontic cement is a promising therapy to inhibit enamel demineralization and WSLs around orthodontic brackets.

Preparation and characterization of intestine PepT1-targeted calcium carbonate nanoparticles

To improve the oral absorption of poorly water-soluble drugs by overcoming the intestinal epithelium barrier, calcium carbonate nanoparticles targeting to intestine peptide transporter 1（Pep T1） were fabricated by modification of the surface of calcium carbonate nanoparticles with Gly-Sar. Gly-Sar-conjugated TPGS was successfully synthesized and characterized, and coumarin 6-loaded Gly-Sar modified calcium carbonate nanoparticles were then prepared and characterized to have a nano-scaled size of about 193 nm in diameter, cracked surface morphology under a scanning electron microscope, and high drug loading efficiency（60.5±5.9）%. Moreover, the Gly-Sar-modified calcium carbonate nanoparticles exhibited better drug loading stability during the process of their transcellular transport, and evidently enhanced intestinal absorption of poorly water-soluble agents. Therefore, the designed intestine Pep T1-targeted calcium carbonate nanoparticles might have a promising potential for oral delivery of poorly water-soluble drugs.

Effects of grafting cell penetrate peptide and RGD on endocytosis and biological effects of Mg-CaPNPs-CKIP-1 siRNA carrier system in vitro

Calcium phosphate nanoparticles(CaPNPs)have good biocompatibility as gene carriers;however,CaPNPs typically exhibit a low transfection efficiency.Cell penetrate peptide(TAT)can increase the uptake of nanoparticles but is limited by its non-specificity.Grafting adhesion peptide adhesion peptide on carriers can enhance their targeting.The Plekho1 gene encodes casein kinase-2 interacting protein-1(CKIP-1),which can negatively regulate osteogenic differentiation.Based on the above,we produced a Mg-CaPNPs-RGD-TAT-CKIP-1 siRNA carrier system via hydrothermal synthesis,silanization and adsorption.The effects of this carrier system on cell endocytosis and biological effects were evaluated by cell culture in vitro.The results demonstrate that CaPNPs with 7%Mg(60 nm particle size,short rod shape and good dispersion)were suitable for use as gene carriers.The carrier system boosted the endocytosis of MG63 cells and was helpful for promoting the differentiation of osteoblasts,and the dual-ligand system possessed a synergistic effect.The findings of this study show the tremendous potential of the Mg-CaPNPs-RGD-TAT-CKIP-1 siRNA carrier system for efficient delivery into cells and osteogenesis inducement.

Preparation and characterization of pH-sensitive calcium carbonate-chlorin e6 nanoparticles for photodynamic therapy

In the present study,we combined CaCO_(3)NPs and Ce6 to construct CaCO_(3)-Ce6 nanoparticles (NPs).CaCO_(3)-Ce6 NPs were characterized in terms of particle size,zeta potential,UV-Vis absorption spectrum,fluorescence spectrum,FTIR spectrum,and pH-responsive behavior.The reactive oxygen species (ROS) generation in vitro was measured in 4T1 cells.The results showed that CaCO_(3)-Ce6 NPs were uniform-sized NPs with excellent fluorescence properties and pH-responsive behavior.The ability of ROS generation by CaCO_(3)-Ce6 NPs was stronger compared with Ce6 in 4T1 cells because Ca;could enhance the ROS generation,which could contribute to a stronger anti-tumor effect.

Effect of sodium alginate/phosphate-stabilized amorphous calcium carbonate nanoparticles on chitosan membranes

Biodegradable chitosan(CS)films can meet the demand for sustainable development.However,the performance of pure CS membrane still exists a particular gap compared with the traditional film.Inorganic nanomaterials with the controllable release are added to improve its physical and chemical properties.Herein,a series of CS/phosphate-stabilized amorphous calcium carbonate(CS/ACCP)and CS/sodium alginate/ACCP(CS/Alginate/ACCP)composite films were prepared by the flow method.The effects of ACCP and Alginate/ACCP nanoparticles on the physical and chemical properties of the composite membrane were investigated.The results showed that the composite nanoparticles could significantly improve CS film’s compactness,hydrophobicity,and mechanical properties and enhance its ultraviolet(UV)blocking ability,water resistance,and water vapor blocking ability.When the number of nanoparticles was 8%,the mechanical properties of the CS composite membrane reached optimum value,and the comprehensive performance was better.In addition,the controlled-release properties of CS composite membranes were also studied,and the antioxidant,antibacterial,biocompatibility,and fresh-keeping effects of the composite membranes were explored.The results indicated that the CS composite membranes had not only excellent bacteriostatic(72%)properties(Escherichia coli)but also presented well fruit preservation(15 days)properties(sugar orange).In particular,the controlled release range of CS composite membrane at 12 h was between 30%and 90%,which provided a theoretical basis for its use as an edible membrane.Therefore,based on ACCP and Alginate/ACCP nanoparticles,CS composite membranes with more excellent application value in the biological field were prepared through further optimization design.

A simple granulation technique for preparing high-porosity nano copper oxide(Ⅱ) catalyst beads

A simple and efficient method was developed for fabricating spherical granules of CuO catalyst via a three-step procedure. In the first step, copper oxide nanoparticles were synthesized by hydrothermal decomposition of copper nitrate solution under supercritical condition. Then, they were immobilized in the polymeric matrix of calcium alginate, and followed by high-temperature calcination in an air stream as the third step, in which carbonaceous materials were oxidized, to result in a pebble-type catalyst of high porosity. The produced CuO nanoparticles were characterized by transmission electron microscopy （TEM） that revealed an average size of 5 nm, X-ray diffractometry （XRD）, and thermo gravimetric （TG） analysis. The catalysts were further investigated by BET test for measurement of their surface area, and by temperature-programmed reduction analysis （H2-TPR） for determination of catalytic activity. The results demonstrated that immobilization of the CuO nanoparticle in the polymeric matrix of calcium alginate, followed by calcination at elevated temperatures, could result in notable mechanical strength and enhanced catalytic activity due to preservation of the high surface area, both valuable for practical applications.