Analytical strategy for studying the formation and stability of multilayered films containing gold nanoparticles.

The design of layer-by-layer (LbL) polyelectrolyte films including nanoparticles is a growing field of innovation in a wide range of biomedical applications. Gold nanoparticles (AuNPs) are very attractive for further biomolecule coupling to induce a pharmacological effect. Nanostructured LbL films coupled with such metallic species show properties that depend on the conditions of construction, i.e. the polymer nature and dissolution buffer. Tripartite LbL films (polycation, AuNP, and polyanion) were evaluated using two different polycationic polymers (poly(allylamine hydrochloride) (PAH), poly(ethylene imine) (PEI)) and various medium conditions (salts, i.e. phosphate, Tris or Tris-NaCl buffers, and concentration). AuNP incorporation and film stability were analysed by visible spectrophotometry, capillary zone electrophoresis, a quartz crystal microbalance, and high-performance liquid chromatography. The ideal compromise between AuNP loading and film stability was obtained using PAH prepared in Tris-NaCl buffer (0.01-0.15 M). This condition allowed the formation of a LbL film that was more stable than the film with PEI and provided an AuNP quantity that was 4.8 times greater than that of the PAH-PBS-built film. In conclusion, this work presents an analytical strategy for the characterization of nanostructured multilayer films and optimization of LbL films enriched with AuNPs to design biomedical device coatings.

Production of cheese from donkey milk as influenced by addition of transglutaminase.

Donkey milk is characterized by low contents of total solids, fat, and caseins, especially κ-casein, which results in formation of a very weak gel upon renneting. The objective of this study was to evaluate the effect of fortification of donkey milk with microbial transglutaminase (MTGase) for cheesemaking in relation to different enzyme addition protocols (patterns, PAT). Four independent trials were performed using MTGase (5.0 U/g of milk protein) according to the following experimental patterns: control (no MTGase addition); MTGase addition (40°C) 15 min before starter inoculation (PAT1); addition of MTGase to milk simultaneously with starter culture (40°C) (PAT2); and MTGase addition simultaneously with rennet (42°C) in acidified milk (pH 6.3) (PAT3). Evolution of pH during acidification, cheesemaking parameters, and proximal composition and color of cheese at 24 h were recorded. The protein fractions of cheese and whey were investigated by urea-PAGE and sodium dodecyl sulfate-PAGE. Addition of MTGase had no significant effect on moisture, protein, fat, or cheese yield. The addition of MTGase with rennet (PAT3) improved curd firmness compared with the control. Among the different patterns of MTGase addition, PAT3 reduced gel formation time, time between rennet addition and cheese molding, and weight loss of cheese at 24 h. The PAT3 treatment also resulted in the lowest lightness and highest yellowness color values of the cheese. Sodium dodecyl sulfate-PAGE of cheeses revealed that MTGase modified the protein pattern in the high-molecular-weight zone (range 37-75 kDa) compared with the control. Of the MTGase protocols, PAT3 showed better casein retention in cheese, as confirmed by the lanes of α- and ß-caseins in the electropherogram of the whey, which was subtler for this protocol. In conclusion, MTGase may be used in cheese production from donkey milk to improve curd firmness; MTGase should be added simultaneously with the rennet.

Physicochemical evaluation of low-fat yoghurt produced with microbial transglutaminase.

BACKGROUND: Currently consumers demand low-fat or non-fat yoghurt but their physical properties are less attractive than those of full-fat yoghurt. It was reported that microbial transglutaminase (TG) can be used in the production of low-fat yoghurt. The aim of this work was to evaluate the effect of TG on low-fat yoghurt to improve their physicochemical and textural properties to approach to those of full-fat yoghurt. Two TG application methods (addition before fermentation or simultaneous addition with the starter), three dose levels and TG origin were evaluated. Results were compared with commercial low-fat and full-fat yoghurts. RESULTS: No significant differences between application methods were observed. Simultaneous addition of TG was preferred because additional time-consuming steps are not required. The best dose was 1 U TG g-1 of protein that allowed a firmness higher (4.25 N) than that of commercial low-fat (3.05 N) and full-fat (4.43 N) yoghurts to be achieved. This implies that intermediate values of TG will permit the same firmness as commercial yoghurts to be obtained. It was observed some differences by the TG origin may be due to excipients. CONCLUSION: TG may be used to replace stabilizers in the production of low-fat yoghurt as it improves texture and avoids initial syneresis. © 2018 Society of Chemical Industry.

Microfluidic Assembly: An Innovative Tool for the Encapsulation, Protection, and Controlled Release of Nutraceuticals.

Nutraceuticals have been gradually accepted as food ingredients that can offer health benefits and provide protection against several diseases. It is widely accepted due to potential nutritional benefits, safety, and therapeutic effects. Most nutraceuticals are vulnerable to the changes in the external environment, which leads to poor physical and chemical stability and absorption. Several researchers have designed various encapsulation technologies to promote the use of nutraceuticals. Microfluidic technology is an emerging approach which can be used for nutraceutical delivery with precise control. The delivery systems using microfluidic technology have obtained much interest in recent years. In this review article, we have summarized the recently introduced nutraceutical delivery platforms including emulsions, liposomes, microspheres, microgels, and polymer nanoparticles based on microfluidic techniques. Emphasis has been made to discuss the advantages, preparations, characterizations, and applications of nutraceutical delivery systems. Finally, the challenges, several up-scaling methods, and future expectations are discussed.

Synthesis, Physicochemical Analysis, and Side Group Optimization of Degradable Dipeptide-Based Polyphosphazenes as Potential Regenerative Biomaterials.

We report the synthesis and physicochemical analysis of mixed-substituent dipeptide-based polyphosphazene polymers, poly[(glycineethylglycinato) x (phenylphenoxy) y phosphazene] (PNGEG x PhPh y ) and poly[(ethylphenylalanato) x (glycineethylglycinato) y phosphazene] (PNEPA x GEG y ), using glycylglycine ethyl ester (GEG) as the primary substituent side group and cosubstituting with phenylphenol (PhPh) and phenylalanine ethyl ester (EPA), respectively. The suitability of the cosubstituted polyphosphazenes to regenerative engineering was evaluated. The physicochemical evaluation revealed that the molecular weights, glass transition temperatures, hydrophilicity, and mechanical properties could be modulated by varying the compositions of the side groups to obtain a variety of properties. The PNEPA25GEG75 and PNGEG75PhPh25 polymers exhibited the most promising physicochemical properties. These two polymers were further subjected to in vitro hydrolysis and cell proliferation studies using poly(lactic-co-glycolic acid) (PLAGA) as a control. The hydrolysis experiments revealed that the two polymers hydrolyzed to near-neutral pH media (~5.3 to 7.0) in a relatively slow fashion, whereas a pH value as low as 2.2 was obtained for the PLAGA media over 12 weeks of degradation study. Furthermore, the two polymers showed continuous MC3T3 cell proliferation and growth in comparison to PLAGA over a 21-day culture period. These findings establish that cosubstitution of different side groups of polyphosphazenes and exploitation of the hydrogen-bonding capacity of peptide bonds in GEG offer a flexible tool that can be employed to make new and fascinating polymeric biomaterials with different and tailored properties that can suit different regenerative needs.

Sanitary quality of reused water for irrigation in agriculture in Brazil / Qualidade sanitária de águas de reúso para irrigação na agricultura no Brasil

A água de reúso é um recurso proveniente de efluentes tratados e pode ser uma fonte alternativa de água para agricultura. No entanto, é importante a avaliação da sua qualidade para não causar agravos a saúde ambiental e humana. O objetivo foi avaliar a qualidade sanitária (bacteriológica, físicas e químicas) de amostras de água de reúso para irrigação da agricultura, de acordo com padrões estabelecidos em normativas brasileiras e internacional. Foram realizadas análises bacteriológicas, sendo os resultados comparados com a norma da Associação Brasileira de Normas Técnicas NBR nº 13.969/1997. E foram feitas análises físicas e químicas das amostras de água de reúso, sendo os resultados comparados com os padrões das normativas: Resolução do Conselho Estadual de Meio Ambiente do Ceará nº 2 de 2017; Resolução do Conselho Estadual de Recursos Hídricos da Bahia nº 75 de 2010; e "Guidelines for Water Reuse" from the U.S. Environmental Protection Agency - EPA. As análises bacteriológicas mostraram que as amostras "clorada" e "polida" estavam próprias para agricultura, de acordo com as normativas brasileiras. No entanto a amostra "biológica" estava imprópria para uso, apresentando nível elevado de coliformes termotolerantes (25,800 CFU/mL). Segundo as análises bacteriológicas e físico-químicas apenas a amostra de reúso "polida" estava própria para reúso agrícola. O estudo mostrou a importância da forma de tratamento de água de reúso para qualidade sanitária da água, e isso é fundamental a criação de lei federal de reúso agrícola, a fim de evitar danos à saúde humana e ambiental.

Evaluation of directly observed treatment short courses at a secondary health institution in Ibadan, Oyo State, Southwestern Nigeria.

OBJECTIVE: To evaluate the success rate of tuberculosis intervention programme at a specialist hospital in Ibadan, Nigeria through a retrospective study as well as carry out physicochemical evaluation of anti-tuberculous agents as a way of eliminating drug-related failure. METHODS: The retrospective study involved the use of quarterly tuberculosis central register at the Government Chest Hospital, Ibadan between 1st quarter (2003) to 4th quarter (2009). Relevant data were extracted from these register with the aid of data collection forms. The basic physicochemical analyses of the drugs given to the patients were also carried out using the International Pharmacopoeia methods. RESULTS: All the drugs examined for their physicochemical properties passed the International Pharmacopeia recommended tests. A total number of 1 260 patients enrolled at the hospital were assessed through case notes. This comprises of 59.4% males of which 69.23% new cases were also males. There was a significant (P<0.05) patient enrollment across the quarters for the seven years. An overall 80.24% cure rate over the 7-period was obtained which is less than the WHO target of 85%. Cure rates were better in females than males. Failure treatment outcomes such as positive (1.51%), deaths (8.73%), defaulted (3.33%) and transferred out (5.95%) were recorded though not statistically significant (P>0.05). Failure rates in all categories were higher in males than females (P>0.05). CONCLUSIONS: More enlightenment and counseling is still required to meet up with the target for TB control.