Dental caries and periodontal disease are widespread diseases for which microorganism infections have been identified as the main etiology. Silver nanoparticles (Ag Nps) were considered as potential control oral bacteria infection agent due to its excellent antimicrobial activity and non acute toxic effects on human cells. In this work, stable Ag Nps with different sizes (~5, 15 and 55 nm mean values) were synthesized by using a simple reduction method or hydrothermal method. The Nps were characterized by powder X-ray diffraction, transmission electron microscopy and UV-vis absorption spectroscopy. The antibacterial activities were evaluated by colony counting assay and growth inhibition curve method, and corresponding minimum inhibitory concentration (MIC) against five anaerobic oral pathogenic bacteria and aerobic bacteria E. coli were determined. The results showed that Ag Nps had apparent antibacterial effects against the anaerobic oral pathogenic bacteria and aerobic bacteria. The MIC values of 5-nm Ag against anaerobic oral pathogenic bacteria A. actinomycetemcomitans, F. nuceatum, S. mitis, S. mutans and S. sanguis were 25, 25, 25, 50 and 50 μg/mL, respectively. The aerobic bacteria were more susceptible to Ag NPs than the anaerobic oral pathogenic bacteria. In the mean time, Ag NPs displayed an obvious size-dependent antibacterial activity against the anaerobic bacteria. The 5-nm Ag presents the highest antibacterial activity. The results of this work indicated a potential application of Ag Nps in the inhibition of oral microorganism infections.

SignificanceOur coarse-grained molecular dynamics (CGMD) simulations show that the deposition of nanoscale knobs, rather than spectrin network remodeling, is the primary cause of the dramatically increased stiffness of the Plasmodium falciparum (Pf)-infected red blood cell (RBC) membranes. Our analyses further reveal that the knobs stiffen the RBC membrane in a unique manner by simultaneously harnessing composite strengthening, strain hardening, and knob density-dependent vertical coupling effects. In addition to providing a fundamental understanding of the stiffening mechanism of Pf-infected RBCs, our simulation results suggest potential targets for antimalarial therapies.

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Lithium-ion batteries are commonly used as sources of power for electric vehicles (EVs). Battery safety is a major concern, due to a large number of accidents, for which short circuit has been considered as one of the main causes. Therefore, diagnosing and prognosticating short circuit are of great significance to improve EV safety. This work reviews the current state of the art about the diagnosis and prognosis of short circuit, covering the method and the key indicators. The findings provide important insights regarding how to improve the battery safety.

Hybrid alumina nanoparticles with pepsin were prepared in a controlled and efficient manner. Phosphorylated pepsin can be coupled to alumina through the interaction between phosphoserine on pepsin and the alumina surface in an orientation-specific manner. A comparison of data obtained with nanoparticles and microsized alumina particles reveals that the conjugated pepsin retained much higher enzymatic activity when it was immobilized on nanoparticles mainly because of the lack of diffusion limitations of the substrate. Additionally, upon attachment to the alumina nanoparticles, the thermal stability of pepsin is enhanced. The coupled enzyme can be quantitatively released by simply incubating the hybrid nanoparticles with phosphate buffer.Introduction. Nanotechnology has emerged as a powerful tool in the fabrication of materials having superior and often unique properties. 1-4 The incorporation of biological molecules into these materials should expand the range of potential applications to include nanoscale biosensors and biocatalysts. 5 Previous studies on the conjugation of nanoparticles with biomolecules such as proteins and DNA used mainly gold-, silver-, silica-, and nickel-based nanoparticles as well as quantum dots. 6 Several methods have been employed for the attachment of biomolecules on nanoparticles including binding through a thiol group to gold 7,8 and maleimido-modified fullerenes, 9 through amino groups to carboxyl-functionalized paricles, 10 through a polyhistidine tag to nickel, 11 or through electrostatic interactions to charged nanoparticles. 12 Herein, we report a new class of hybrid nanoparticles composed of nanosized alumina functionalized with an enzyme. We demonstrate, using pepsin as a model enzyme, an orientation-specific, efficient, and reversible means to couple phosphorylated proteins to alumina nanoparticles through the interaction between the phosphoryl group and the alumina surface. When alumina nanoparticles are used in this manner, the decrease in enzymatic activity is minimal. A unique property of these hybrid nanoparticles is the ability to release the coupled pepsin quantitatively (98%) in a controlled manner.Pepsin is an enzyme essential to the digestion process in animals. The optimal pH for its activity is 2.0, which is compatible with that of alumina. The enzyme has a total of