Chain-like assembly of gold nanoparticles on artificial DNA templates via 'click chemistry'

We present a new type of azide-functionalized gold nanoparticle and their coupling to an alkyne-modified DNA duplex using the copper(I)-catalyzed Huisgen cycloaddition ('click chemistry'), resulting in a chain-like assembly of nanoparticles on the DNA template.     

Bone healing process in critical-sized defects by rhBMP-2 using poloxamer gel and collagen sponge as carriers

The bone morphogenetic protein type 2, is an osteoinduction protein, but new carriers to improve its actions are being studied in recent researches. The objective of this study was to evaluate the poloxamer gel as potential carrier of the rhBMP-2 during the bone healing process and verify if the collagen sponge can improve this process. Fifty-six male Wistar rats were used, which were divided into two groups, considering two periods of time. Thus, each one of these groups was divided in four groups with seven animals each, according to the treatment and the defect filled by 4 microg rhBMP-2 in aqueous solution, 4 microg rhBMP-2 in aqueous solution+collagen sponge, 4 microg rhBMP-2 combined with poloxamer gel, and 4 microg rhBMP-2 combined with poloxamer gel+collagen sponge. After 2 and 4 weeks, respectively, animals were perfused and the hemi-mandibles removed for histological analysis. Statistical analysis of the data showed significant difference between all analyzed groups (p<0.01), and between the periods of time (p=0.0118). There was no interaction between the applied treatment and considered periods of time (p=0.642). Results showed that the rhBMP-2 used in this study was able to induce bone regeneration and had its action optimized when combined to the used carriers, being the bone repair time-dependent.     

Host–guest system of 4-nerolidylcatechol in 2-hydroxypropyl-β-cyclodextrin: preparation, characterization and molecular modeling

The interaction of 4-nerolidylcatechol (4-NRC), a potent antioxidant agent, and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) was investigated by the solubility method using Fourier transform infrared (FTIR) methods in addition to UV–Vis, ¹H-nuclear magnetic resonance (NMR) spectroscopy and molecular modeling. The inclusion complexes were prepared using grinding, kneading and freeze-drying methods. According to phase solubility studies in water a B_S-type diagram was found, displaying a stoichiometry complexation of 2:1 (drug:host) and stability constant of 6494 ± 837 M^?1. Stoichiometry was established by the UV spectrophotometer using Job’s plot method and, also confirmed by molecular modeling. Data from ¹H-NMR, and FTIR, experiments also provided formation evidence of an inclusion complex between 4-NRC and HP-β-CD. 4-NRC complexation indeed led to higher drug solubility and stability which could probably be useful to improve its biological properties and make it available to oral administration and topical formulations.     

Direct conversion of electrodeposited nanocrystalline ε-MnO2 into LiMn2O4 by microwave calcination

Journal of Solid State Electrochemistry - Firstly, ε-MnO2 films with good adhesion and high surface area were electrolytically deposited on platinum plates. After being soaked for...