Assessment of novel diazinon immunoassays for water analysis

Diazinon is a broad organophosphate insecticide used in agricultural and other treatments, resulting in widespread water contamination. The development of easy-to-use screening immunoanalytical methods is an interesting tool to study environmental pollution impact. Two novel strategies for diazinon hapten synthesis are addressed. One of them attaches the spacer arm to the oxygen atom of the diazinon aromatic ring. The other one retains the diazinon basic structure linking the spacer to an aromatic carbon. A total of eight diazinon haptens were synthesized, demonstrating that they are suitable for immunoreagent (protein conjugates and polyclonal antibodies) production. The optimized ELISA is based on conjugate-coated format and had a detection limit of 0.40 microg/L, showing little or no cross-reactivity to similar tested compounds. The immunoassays were used as a tool to quantify diazinon in natural waters. Results are in agreement with those given by GC-MS reference method. Mean recoveries ranging between 99% and 105% confirm the potential of our approach to determine diazinon in samples without purification or preconcentration steps, being applied as a screening method for field monitoring of diazinon in river waters.     

Production of sensory compounds by means of the yeast Dekkera bruxellensis in different nitrogen sources with the prospect of producing cachaça

The distilled spirit made from sugar cane juice, also known as cachaça, is a traditional Brazilian beverage that in recent years has increased its market share among international distilled beverages. Several volatile compounds produced by yeast cells during the fermentation process are responsible for the unique taste and aroma of this drink. The yeast Dekkera bruxellensis has acquired increasing importance in the fermented beverage production, as the different metabolites produced by this yeast may be either beneficial or harmful to the end‐product. Since D. bruxellensis is often found in the fermentation processes carried out in ethanol fuel distillation in Brazil, we employed this yeast to analyse the physiological profile and production of aromatic compounds and to examine whether it is feasible to regard it as a cachaça‐producing microorganism. The assays were performed on a small scale and simulated the conditions for the production of handmade cachaça. The results showed that the presence of aromatic and branched‐chain amino acids in the medium has a strong influence on the metabolism and production of flavours by D. bruxellensis. The assimilation of these alternative nitrogen sources led to different fermentation yields and the production of flavouring compounds. The influence of the nitrogen source on the metabolism of fusel alcohols and esters in D. bruxellensis highlights the need for further studies of the nitrogen requirements to obtain the desired level of sensory compounds in the fermentation. Our results suggest that D. bruxellensis has the potential to play a role in the production of cachaça. Copyright © 2014 John Wiley & Sons, Ltd.     

Nanoencapsulation of Gla-Rich Protein (GRP) as a Novel Approach to Target Inflammation

Chronic inflammation is a major driver of chronic inflammatory diseases (CIDs), with a tremendous impact worldwide. Besides its function as a pathological calcification inhibitor, vitamin K-dependent protein Gla-rich protein (GRP) was shown to act as an anti-inflammatory agent independently of its gamma-carboxylation status. Although GRP’s therapeutic potential has been highlighted, its low solubility at physiological pH still constitutes a major challenge for its biomedical application. In this work, we produced fluorescein-labeled chitosan-tripolyphosphate nanoparticles containing non-carboxylated GRP (ucGRP) (FCNG) via ionotropic gelation, increasing its bioavailability, stability, and anti-inflammatory potential. The results indicate the nanosized nature of FCNG with PDI and a zeta potential suitable for biomedical applications. FCNG’s anti-inflammatory activity was studied in macrophage-differentiated THP1 cells, and in primary vascular smooth muscle cells and chondrocytes, inflamed with LPS, TNFα and IL-1β, respectively. In all these in vitro human cell systems, FCNG treatments resulted in increased intra and extracellular GRP levels, and decreased pro-inflammatory responses of target cells, by decreasing pro-inflammatory cytokines and inflammation mediators. These results suggest the retained anti-inflammatory bioactivity of ucGRP in FCNG, strengthening the potential use of ucGRP as an anti-inflammatory agent with a wide spectrum of application, and opening up perspectives for its therapeutic application in CIDs.     

3D simulation of nano/micro cellulose delivery systems for dermic and respiratory applications: Case study of eucalyptus essential oil incorporation

The purpose of this work was to design, develop and optimize different combinations of drug delivery systems (DDS) with nanofibrillated (NFC) and microfibrillated (MFC) cellulose-based materials, as 3D networks, encapsulating eucalyptus essential oil molecules, for dermic and respiratory applications. Experimental and computational approaches were implemented for characterization, modeling studies, and structure porosity optimization. The optimized porous structures were able to retain the desired molecules, resulting in more controlled and uniform release kinetics over time. This methodology allowed for optimizing new bio-based drug delivery systems with controlled porosity, pore dimension and distribution, retention of therapeutic molecules, and uniformity of the 3D network. The results showed that different drug delivery systems with this 3D matrix released the essential oil molecules, improving its stability and prolonging the exposure time, factors that are important to develop promising drug delivery systems in biomaterials fields. Overall, cellulose-based structured biomaterials capable of transporting and releasing essential oil components are representatives of innovative materials that will be used in novel applications, in which the exposure time to the therapeutic molecules constitutes a competitive benefit.     

Impact of silica pore structure on the performance of metallocene catalysts in ethylene gas-phase polymerization

Several commercial silicas were used to support metallocene active centres, and the resulting precatalysts were used to study the impact of the pore size and pore size distribution of the support on the polymerization kinetics and resulting polymer properties. Pore volume distribution played a major role in the fragmentation of silica-supported catalysts, where mesoporous silicas with a narrow distribution in the region obtained higher activities and faster fragmentation than silicas with a broad pore volume distribution. Therefore, it is shown that care must be taken when using standard information on particle porosity, as this quantity can be misleading. It appears that the minimum pore size, particularly on the particle surface, can be a very important parameter even if it does not impact the estimate of the porosity.