Preparation of porous calcium phosphate microspheres with phosphate-containing molecules at room temperature for drug delivery and osteogenic differentiation

Calcium phosphate (CaP) has similar chemical properties to those of the inorganic component of human bone tissue, for potential application in drug delivery for the chemotherapy of osteosarcoma. In this work, CaP with a porous microsphere structure has been synthesized using fructose-1,6-bisphosphate (FBP) as the phosphorus source by a simple wet-chemical strategy at room temperature. The CaP porous microspheres, as an organic–inorganic hybrid nano-platform, exhibit good doxorubicin (Dox) loading capacity, and Dox-loading CaP, enhancing the in vitro chemotherapy of osteosarcoma cells. The CaP porous microspheres show high biocompatibility, and induce the osteogenic differentiation of MC3T3-E1. These results indicate that the CaP porous microspheres reported in this study are promising for application as an anti-osteosarcoma drug carrier and osteoinductive material for bone regeneration in the treatment of osteosarcoma.

Porous calcium phosphate microspheres were prepared at room temperature, and displayed potential for application in the chemotherapy of osteosarcoma and osteogenic differentiation.     

Salidroside ameliorates insulin resistance through activation of a mitochondria-associated AMPK/PI3K/Akt/GSK3β pathway

Background and Purpose

Recent reports have suggested that salidroside could protect cardiomyocytes from oxidative injury and stimulate glucose uptake in skeletal muscle cells by activating AMP-activated protein kinase (AMPK). The aim of this study was to evaluate the therapeutic effects of salidroside on diabetic mice and to explore the underlying mechanisms.

Experimental Approach

The therapeutic effects of salidroside on type 2 diabetes were investigated. Increasing doses of salidroside (25, 50 and 100 mg·kg⁻¹·day⁻¹) were administered p.o. to db/db mice for 8 weeks. Biochemical analysis and histopathological examinations were conducted to evaluate the therapeutic effects of salidroside. Primary cultured mouse hepatocytes were used to further explore the underlying mechanisms in vitro.

Key Results

Salidroside dramatically reduced blood glucose and serum insulin levels and alleviated insulin resistance. Hypolipidaemic effects and amelioration of liver steatosis were observed after salidroside administration. In vitro, salidroside dose-dependently induced an increase in the phosphorylations of AMPK and PI3K/Akt, as well as glycogen synthase kinase 3β (GSK3β) in hepatocytes. Furthermore, salidroside-stimulated AMPK activation was found to suppress the expression of PEPCK and glucose-6-phosphatase. Salidroside-induced AMPK activation also resulted in phosphorylation of acetyl CoA carboxylase, which can reduce lipid accumulation in peripheral tissues. In isolated mitochondria, salidroside inhibited respiratory chain complex I and disturbed oxidation/phosphorylation coupling and moderately depolarized the mitochondrial membrane potential, resulting in a transient increase in the AMP/ATP ratio.

Conclusions and Implications

Salidroside exerts an antidiabetic effect by improving the cellular metabolic flux through the activation of a mitochondria-related AMPK/PI3K/Akt/GSK3β pathway     

Development of a Pichia pastoris whole-cell biocatalyst with overexpression of mutant lipase I PCLG47I from Penicillium cyclopium for biodiesel production

Penicillium cyclopium lipase I (PCL) is a thermolabile triacylglycerol lipase with very low activity against monoacylglycerols, and there have been no reports on the transesterification of oil to produce biodiesel. A mutant PCL^G47I with an improved thermostability was previously obtained through replacing Gly47 with Ile in PCL. In this study, a novel Pichia pastoris whole-cell biocatalyst (WCB) with overexpression of PCL^G47I was constructed and characterized for biodiesel production from soybean oil. The optimum conditions for biodiesel preparation were 1 g soybean oil, 1 : 2 initial oil/methanol molar ratio with 3 times methanol addition of 1 : 0.75 oil/methanol molar ratio at 4 h intervals, 7% water content, 400 U lipase, temperature of 25 °C, and reaction time of 20 h. Under the optimum conditions, the FAME yield reached 60.7% and remained 47.3% after 4 batch cycles, and no glycerol was generated as a byproduct. These findings indicated that this WCB is a promising biocatalyst for biodiesel production in a relatively cost-effective manner. Additionally, the resulting enzymatic process may provide a potential method for biodiesel production at an industrial scale.

Biodiesel is efficiently produced by a lipase whole-cell biocatalyst with high activity and thermostability at low temperature.     

Detection of resveratrol by phosphorescence quantum dots without conjunction and mutual impact exploration

In this study, a convenient and sensitive method for the detection of resveratrol was established based on phosphorescence quenching of resveratrol for MPA-capped Mn:ZnS QDs. The quenching intensity was in proportion to the concentration of resveratrol within a certain range. Under optimal conditions, the present assay was valid for detecting resveratrol in the range from 0.03 μM to 14 μM with a detection limit of 0.01 μM. The mechanism of action was also explored, and its application in actual samples was also demonstrated with satisfactory results. This study aims to provide a convenient method for the detection of resveratrol.

In this study, a convenient and sensitive method for the detection of resveratrol was established based on phosphorescence quenching of resveratrol for MPA-capped Mn:ZnS QDs.     

Biological effect of food additive titanium dioxide nanoparticles on intestine: an in vitro study

Titanium dioxide nanoparticles (TiO₂ NPs) are widely found in food‐related consumer products. Understanding the effect of TiO₂ NPs on the intestinal barrier and absorption is essential and vital for the safety assessment of orally administrated TiO₂ NPs. In this study, the cytotoxicity and translocation of two native TiO₂ NPs, and these two TiO₂ NPs pretreated with the digestion simulation fluid or bovine serum albumin were investigated in undifferentiated Caco‐2 cells, differentiated Caco‐2 cells and Caco‐2 monolayer. TiO₂ NPs with a concentration less than 200 µg ml^–1 did not induce any toxicity in differentiated cells and Caco‐2 monolayer after 24 h exposure. However, TiO₂ NPs pretreated with digestion simulation fluids at 200 µg ml^–1 inhibited the growth of undifferentiated Caco‐2 cells. Undifferentiated Caco‐2 cells swallowed native TiO₂ NPs easily, but not pretreated NPs, implying the protein coating on NPs impeded the cellular uptake. Compared with undifferentiated cells, differentiated ones possessed much lower uptake ability of these TiO₂ NPs. Similarly, the traverse of TiO₂ NPs through the Caco‐2 monolayer was also negligible. Therefore, we infer the possibility of TiO₂ NPs traversing through the intestine of animal or human after oral intake is quite low. This study provides valuable information for the risk assessment of TiO₂ NPs in food. Copyright © 2015 John Wiley & Sons, Ltd.     

Transmission Risk from Imported Plasmodium vivax Malaria in the China–Myanmar Border Region

Malaria importation and local vector susceptibility to imported Plasmodium vivax infection are a continuing risk along the China–Myanmar border. Malaria transmission has been prevented in 3 border villages in Tengchong County, Yunnan Province, China, by use of active fever surveillance, integrated vector control measures, and intensified surveillance and response.     

Facile morphology control of 3D porous CeO2 for CO oxidation

3D porous CeO₂ with various morphologies was successfully synthesized via a facile precipitation using glycine as the soft bio-template. During the synthesis, it was demonstrated that the morphology of CeO₂ depended on the molar ratio of reactants. Furthermore, the catalytic performance towards CO oxidation of the as-synthesized CeO₂ with different morphologies was investigated. CeO₂ with a bowknot shape showed excellent catalytic performance, giving complete CO conversion at 370 °C, due to its properties of much higher oxygen vacancies, loosely packed pore structure and larger specific surface area.

Different morphologies of CeO₂ were obtained via a green and facial method, which realized CO complete conversion at 370 °C.     

Insight into the significant roles of microstructures and functional groups on carbonaceous surfaces for acetone adsorption

To understand the roles of pore structures and functional groups on acetone adsorption, activated carbons (ACs) with different properties were obtained by surface modification. XRD, SEM, TEM and nitrogen adsorption were used to identify the structural characteristics of the ACs, while TG-DTA, FTIR, XPS and Boehm titration were applied to analyse the surface chemistries. The microporous surface areas showed a positive linear correlation to the acetone adsorption amounts, and increasing the carboxylic groups could improve the uptake of strongly adsorbed acetone. HNO₃ modified AC (AC-N) was found to exhibit an excellent adsorption capacity of 5.49 mmol g⁻¹, which might be attributed to the developed microporous structures and abundant carboxylic groups. The desorption activation energies (E_d) of strongly adsorbed acetone on AC-N and AC were both determined to be 81.6 kJ mol⁻¹, indicating the same adsorption sites on different activated carbons, suspected to be carboxylic groups. The possible adsorption mechanism of acetone on carbonaceous surfaces was also proposed.

To understand the roles of pore structures and functional groups on acetone adsorption, activated carbons (ACs) with different properties were obtained by surface modification.