Search

Emulsions stabilized by a mixture of emulsifiers may show a tailored functionality depending on the compatibility of the emulsifiers employed. This was proposed in a previous work dealing with distinct lipolysis kinetics of citrus pectin (CP) and Tween 80 (TW80) based emulsions. CP provided a fast a high extent of gastric lipid hydrolysis, TW80 presented negligible digestion and emulsions stabilized with mixtures presented intermediate lipolysis kinetics. The current research work aimed to investigate the interfacial mechanisms underlying gastric lipolysis to further understand the encountered behavior on a fundamental basis. This was achieved by monitoring the interfacial tension kinetics and measuring the interfacial rheology of interfacial layers during in vitro digestion using a modified pendant drop technique. This allowed the correlation of emulsions in vitro lipolysis kinetics and interfacial phenomena during digestion. Two extremely different interfacial tension kinetics were observed when single layers of CP versus TW80 and intermediate kinetics were observed for the binary interfacial layers, importantly correlating with results obtained with emulsions. These findings are discussed in detail and confirm that competitive adsorption between emulsifiers and lipase (e.g. orogenic displacement) is a key factor determining the lipolysis kinetics of emulsions stabilized by mixed emulsifiers. ispartof: Food Hydrocolloids vol:128 status: published

Novel composite hydrogels of poly(acrylamide) (PAAm) and starch, at different ratios, were studied as potential platforms for controlled release of amoxicillin. The composite hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and swelling kinetic measurements. The morphology analysis revealed the presence of starch granules well embedded within the PAAm network. The increase in starch content increased the rate of water uptake and the swelling degree at equilibrium. The amoxicillin release kinetics was sensitive to pH and temperature conditions. The in vitro bacterial growth inhibition of antibiotic-loaded hydrogels was tested though disc diffusion assays with Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, and a carbapenemase producer Pseudomonas aeruginosa strain. The optimal release profile at physiological conditions and the powerful bacteria growth inhibition effects of amoxicillin-loaded hydrogels evidenced its potential for biomedical applications, particularly in oral administration and the local treatment of bacterial infections.

This work has been supported by project RTI2018-101309-B-C21 funded by MCIN/AEI/10.13039/501100011033/FEDER. The authors are also grateful to the "Mancomunidad de los Pueblos de la Alpujarra Granadina" for the funds raised and supplied for this research by "Solidaridad entre montanas" project. This work was also partially supported by the Biocolloid and Fluid Physics Group (ref. PAI-FQM115) of the University of Granada (Spain). JMV acknowledges support from project Project PID2020-116615RA-I00 funded by MCIN/AEI/10.13039/501100011033. This work has been done in the framework of the doctorate of AAG in the Doctoral Programme in Biomedicine (B11/56/1) of the University of Granada. Funding for open access charge: Universidad de Granada/CBUA., Liquid lipid nanocapsules are oil droplets surrounded by a protective shell, which enable high load and allow controlled delivery of lipophilic compounds. However, their use in food formulations requires analysing their digestibility and interaction with mucin. Here, serum albumins and hyaluronic acid shelled olive oil nanocapsules are analysed to discern differences between human and bovine variants, the latter usually used as model system. Interfacial interaction of albumins and hyaluronic acid reveals that human albumin presents limited conformational changes upon adsorption, which increase by complexation with the polysaccharide present at the interface. The latter also promotes hydrophobic interactions with mucin, especially at pH 3 and protects albumin interfacial layer under in vitro gastric digestion. The interfacial unfolding induced in human albumin by hyaluronic acid facilitates in vitro lipolysis while its limited conformational changes provide the largest protection against in vitro lipolysis., Mancomunidad de los Pueblos de la Alpujarra Granadina, Biocolloid and Fluid Physics Group of the University of Granada (Spain) PAI-FQM115, University of Granada B11/56/1 Universidad de Granada/CBUA RTI2018-101309-B-C21 MCIN/AEI/10.13039/501100011033/FEDER PID2020-116615RA-I00 MCIN/AEI/10.13039/501100011033

In this study, we report the lowest energy structure of bare Cu13 nanoclusters as a pair of enantiomers at room temperature. Moreover, we compute the enantiomerization energy for the interconversion from minus to plus structures in the chiral putative global minimum for temperatures ranging from 20 to 1300 K. Additionally, employing nanothermodynamics, we compute the probabilities of occurrence for each particular isomer as a function of temperature. To achieve that, we explore the free energy surface of the Cu13 cluster, employing a genetic algorithm coupled with density functional theory. Moreover, we discuss the energetic ordering of isomers computed with various density functionals. Based on the computed thermal population, our results show that the chiral putative global minimum strongly dominates at room temperature.

The inclusion of nanostructures into cross-linked polymer networks allows obtaining nanocomposite hydrogels with suitable multifuncionalities for drug delivery applications. In this work, polypyrrole (PPy) nanoparticles, synthesized by a biocatalytic route, were encapsulated into a hydrogel matrix of poly(vinyl alcohol) (PVA) during its reticulation with glutaraldehyde. The novel composite hydrogels were characterized by infrared spectroscopy, thermogravimetric analysis, swelling kinetic measurements, scanning electron microscopy and cyclic voltammetry. The loading capabilities of PVA/PPy hydrogels were tested for metoprolol, a beta blocker used to treat angina, hypertension and to prevent heart attack. In vitro drug release profiles were obtained without and under electrical stimulations. The kinetics of drug release exhibited a power-law time dependence, typical of hydrogel-based systems. The application of electrical potentials changed the release rate of the drug, increasing or decreasing the delivery rate depending on bias voltage. Composite system of PVA and PPy combines the electrochemical redox properties of the conductive polymer with the swelling capacity and molecular diffusivity associated with PVA network; therefore, it can be considered a potential stimuli-responsive platform for biomedical applications.

Hypothesis The use of polymer-based surfactants in the double-emulsion (water/oil/water, W/O/W) solvent-evaporation technique is becoming a widespread strategy for preparing biocompatible and biodegradable polymeric nanoparticles (NPs) loaded with biomolecules of interest in biomedicine, or biotechnology. This approach enhances the stability of the NPs, reduces their size and recognition by the mononuclear phagocytic system, and protects the encapsulated biomolecule against losing biological activity. Different protocols to add the surfactant during the synthesis lead to different NP colloidal properties and biological activity. Experiments We develop anin vitromodel to mimic the first step of the W/O/W NP synthesis method, which enables us to analyze the surfactant-biomolecule interaction at the O/W interface. We compare the interfacial properties when the surfactant is added from the aqueous or the organic phase, and the effect of pH of the biomolecule solution. We work with a widely used biocompatible surfactant (Pluronic F68), and lysozyme, reported as a protein model. Findings The surfactant, when added from the water phase, displaces the protein from the interface, hence protecting the biomolecule. This could explain the improved colloidal stability of NPs, and the higher biological activity of the lysozyme released from nanoparticles found with the counterpart preparation.

Lowest-energy structures, the distribution of isomers, and their molecular properties depend significantly on geometry and temperature. Total energy computations using DFT methodology are typically carried out at a temperature of zero K; thereby, entropic contributions to the total energy are neglected, even though functional materials work at finite temperatures. In the present study, the probability of the occurrence of one particular Be4B8 isomer at temperature T is estimated by employing Gibbs free energy computed within the framework of quantum statistical mechanics and nanothermodynamics. To identify a list of all possible low-energy chiral and achiral structures, an exhaustive and efficient exploration of the potential/free energy surfaces is carried out using a multi-level multistep global genetic algorithm search coupled with DFT. In addition, we discuss the energetic ordering of structures computed at the DFT level against single-point energy calculations at the CCSD(T) level of theory. The total VCD/IR spectra as a function of temperature are computed using each isomer’s probability of occurrence in a Boltzmann-weighted superposition of each isomer’s spectrum. Additionally, we present chemical bonding analysis using the adaptive natural density partitioning method in the chiral putative global minimum. The transition state structures and the enantiomer–enantiomer and enantiomer–achiral activation energies as a function of temperature evidence that a change from an endergonic to an exergonic type of reaction occurs at a temperature of 739 K.

This chapter provides an overview of the most important aspects that govern the composition, structure, and mechanical properties of interfaces in food emulsions. The main theoretical concepts and the main experimental methods existing traditionally to study fluid interfaces are revised. The characteristics of the pendant drop film balance owing to its versatility and acceptance to work at liquid interfaces are discussed. Then, a detailed analysis of the interfacial properties of adsorbed layers considering individual systems, mixtures, as well as different methods of formation and devices is provided. This knowledge is then applied mechanisms to control stability via interfacial design. The relationships between interfacial magnitudes and physical properties of emulsions are also denoted before discussing the digestion of emulsified systems and the advanced design of food products with tailored functionality.

This chapter provides an overview of the traditional methods used to physically characterize delivery systems in the form of emulsions. Firstly, it reviews methods that are commonly used to study liquid interfaces such as pendant drop tensiometry and Langmuir monolayers. Secondly, it shows methods for physical characterization of emulsions such as droplet size and electrophoretic mobility. Finally, the use of atomic force microscopy to physically characterize interfaces and measure forces between emulsion droplets is presented. As a result, the chapter offers a combined overview of the link between molecular, interfacial, and colloidal properties of possible routes to control stability and delivery via interfacial engineering.

A major challenge in delivering curcumin effectively to the gut is its low solubility. One interesting approach to increase curcumin bioaccessibility is its emulsification. Here, we present curcumin-loaded liquid lipid nanocapsules (LLNs), obtained through olive oil emulsification, in which LLNs are coated by a protective shell composed of Bovine Serum Albumin (BSA) and hyaluronic acid (HA). Bioaccessibility of curcumin is evaluated following a standard in vitro digestion protocol. The presence of HA in the shell increases the amount of curcumin retained in the LLNs after in vitro gastric digestion from ~25% to ~85%. This protective effect occurs when HA binds to BSA in the shell. Moreover, this binding appears to be reinforced under gastric conditions, hence evidencing the crucial role of interfacial composition in protecting encapsulated curcumin. Interfacial engineering of nanoemulsions provides a route to improve the bioaccessibility of encapsulated curcumin at different stages in the gut.

This work was funded by the project CTQ2017-87076-R from the Spanish Ministry of Science and Innovation. Julia Maldonado-Valderrama and Teresa del Castillo-Santaella acknowledge financialsupport from project RTI2018-101309-B-C21. The authors are also very grateful to F. Javier Espejo-Carpio and Marta Padial-Dominguez for providing the whey and blue whiting protein hydrolysates. Funding for open access charge: Universidad de Granada/CBUA., This work investigates the influence of the interfacial properties of whey protein (WPH) and blue whiting protein (BPH) hydrolysates on the physical stability of fish oil-in-water emulsions stabilized with these hydrolysates at pH 2 or 8. Measurements of interfacial tension and dilatational rheology confirmed that pH is a key factor affecting these interfacial properties of WPH and BPH. WPH, when tested at 1 and 10 mg/mL, showed a higher interfacial activity at pH 8 when compared to pH 2 or to BPH at pH 8 or 2, despite having a lower protein content. Moreover, when tested at 0.1 and 1 mg/mL, the dilatational modulus of WPH was significantly higher at pH 8 than at pH 2. These findings correlate with the formation of smaller oil droplets and a more resistant interfacial peptide layer for WPH at pH 8, hence explaining the improved physical stability of the 5% fish oil-in water emulsion stabilized with WPH at pH 8. BPH did not show significant differences in interfacial activity with pH but exhibited significantly higher dilatational elasticity and viscosity at pH 2 compared to pH 8 (when measured at 0.1 mg/mL and 0.01 or 0.1 Hz). This correlates with the formation of stable 5% fish oil-in-water emulsions with BPH at pH 2 but not at pH 8., Spanish Government CTQ2017-87076-R

AS-48 is a bacteriocin with potential application as food biopreservative. In order to optimize its use for oral consumption, we assess the impact of gastrointestinal digestion, both in bulk and adsorbed at the air-water interface. Analysis of AS-48 digestion fragments in bulk by SDS-PAGE, RP-HPLC, and MALDI-TOF proves that the previouspepsinexposition promotes digestion by trypsin/chymotrypsin by exposing new cleavage sites. Regarding adsorbed AS-48, the in vitro digestion profile shows that the conformational change undergone by AS-48 upon adsorption affects its digestibility. Gastrointestinal enzymes cleave only susceptible residues, which are oriented into the aqueous phase, while hydrophobic susceptible residues remain undigested. Evaluation of the elasticity of the adsorbed layer confirms also the presence of undigested AS-48. These results are important towards the use of AS-48 in food formulations; assuring that some intact AS-48 resists digestion guarantees its antibacterial activity throughout the gastrointestinal tract.

In this study, we report the lowest energy structure of bare Cu13 nanoclusters as a pair of enantiomers at room temperature. Moreover, we compute the enantiomerization energy for the interconversion from minus to plus structures in the chiral putative global minimum for temperatures ranging from 20 to 1300 K. Additionally, employing nanothermodynamics, we compute the probabilities of occurrence for each particular isomer as a function of temperature. To achieve that, we explore the free energy surface of the Cu13 cluster, employing a genetic algorithm coupled with density functional theory. Moreover, we discuss the energetic ordering of isomers computed with various density functionals. Based on the computed thermal population, our results show that the chiral putative global minimum strongly dominates at room temperature.

The development of thermosensitive bioadhesive hydrogels as multifunctional platforms for the controlled delivery of microbicides is a valuable contribution for the in situ treatment of vagina infections. In this work, novel semi-interpenetrating network (s-IPN) hydrogels were prepared by the entrapment of linear poly(methyl vinyl ether-alt-maleic anhydride) (PVME-MA) chains within crosslinked 3D structures of poly(N-isopropylacrylamide) (PNIPAAm). The multifunctional platforms were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermal techniques, rheological analysis, swelling kinetic measurements, and bioadhesion tests on porcine skin. The hydrogels exhibited an interconnected porous structure with defined boundaries. An elastic, solid-like behavior was predominant in all formulations. The swelling kinetics were strongly dependent on temperature (25 °C and 37 °C) and pH (7.4 and 4.5) conditions. The s-IPN with the highest content of PVME-MA displayed a significantly higher detachment force (0.413 ± 0.014 N) than the rest of the systems. The metronidazole loading in the s-IPN improved its bioadhesiveness. In vitro experiments showed a sustained release of the antibiotic molecules from the s-IPN up to 48 h (94%) in a medium simulating vaginal fluid, at 37 °C. The thermosensitive and bioadhesive PNIPAAm/PVME-MA systems showed a promising performance for the controlled release of metronidazole in the vaginal environment.

This work has been supported by Ministerio de Ciencia e Innovacion de Espana (under project RTI2018101309BC21) , by the Fundacion Seneca del Centro de Coordinacion de la Investigacion de la Region de Murcia (under Project 20988/PI/18) and by a grant from Ministerio de Economia y Competitividad de Espana (CTQ201787974R) . This research was partially supported by the supercomputing infrastructure of Poznan Supercomputing Centre, and by the einfrastructure program of the Research Council of Norway, and the supercomputer centre of UiTthe Arctic University of Norway. The authors also thankfully acknowledge the computer resources and the technical support provided by the Plataforma Andaluza de Bioinformatica of the University of Malaga. Powered@NLHPC: This research was partially supported by the supercomputing infrastructure of the NLHPC (ECM02), Peripheral targets like pancreatic-lipase appear to be the most suitable pharmacological alternative for obesity, as with orlistat, although its adverse effects limit its use. Therefore, the aim of this work was to identify new natural compounds able to inhibit pancreatic-lipase in an in vitro model. The DrugBank database was used to perform docking calculations. The best fitting-score compounds were further evaluated in vitro. Our data revealed that glutathione-disulphide (GSSG) and silibinin(A) inhibit pancreatic-lipase. This was confirmed by measuring hydrolysis in an emulsion model, obtaining that the suppression of lipid digestion by silibinin(A) was higher than that of GSSG and close to the effect of orlistat. Combined analysis established the existence of different inhibition mechanisms for each compound. In summary, silibinin(A) and GSSG inhibited pancreatic-lipase and, therefore, may be served as promise natural compounds to face with obesity. Further studies comprise the next step to fully validate the suitability of these compounds., Spanish Government RTI2018-101309-B-C21, Fundacion Seneca 20988/PI/18, Ministerio de Economia y Competitividad de Espana CTQ2017-87974-R, Supercomputing infrastructure of Poznan Supercomputing Centre, Einfrastructure program of the Research Council of Norway, Supercomputer centre of UiTthe Arctic University of Norway

Because of the biocompatible and biodegradable properties of poly (lactic-co-glycolic acid) (PLGA), nanoparticles (NPs) based on this polymer have been widely studied for drug/biomolecule delivery and long-term sustained-release. In this work, two different formulation methods for lysozyme-loaded PLGA NPs have been developed and optimized based on the double-emulsion (water/oil/water, W/O/W) solvent evaporation technique. They differ mainly in the phase in which the surfactant (Pluronic®F68) is added: water (W-F68) and oil (O-F68). The colloidal properties of these systems (morphology by SEM and STEM, hydrodynamic size by DLS and NTA, electrophoretic mobility, temporal stability in different media, protein encapsulation, release, and bioactivity) have been analyzed. The interaction surfactant-protein depending on the formulation procedure has been characterized by surface tension and dilatational rheology. Finally, cellular uptake by human mesenchymal stromal cells and cytotoxicity for both systems have been analyzed. Spherical hard NPs are made by the two methods However, in one case, they are monodisperse with diameters of around 120nm (O-F68), and in the other case, a polydisperse system of NPs with diameters between 100 and 500nm is found (W-F68). Protein encapsulation efficiency, release and bioactivity are maintained better by the W-F68 formulation method. This multimodal system is found to be a promising “dual delivery” system for encapsulating hydrophilic proteins with strong biological activity at the cell-surface and cytoplasmic levels.

This paper presents the selective adsorption of bromine-metallic complexes of Au and Ag on composite membranes, as well as the desorption process and redoping of the conducting polymers. The polyaniline (PANI) and polypyrrole (PPy) membranes exhibited relevant adsorption properties. 72% for gold and 98% for silver with PANI, 50% for gold and 97% for silver with PPy, in bromine complexes. The adsorption capabilities of the composite membranes were attributed to the ion exchange between the dopant and the AuBr 4 − or AgBr 2 − complexes. Both materials fitted to a Langmuir isotherm. PANI-based membranes reached 31.4% of gold and 54.4% of silver desorption whereas PPy-based membranes reached 54% of gold and 28.8% of silver. Redoping studies suggested the potential reuse of the PANI-based membranes at least for six cycles of the adsorption/desorption process. The preparation of cellulose acetate membranes modified with poly (acrylic acid) and triphenyl phosphate and coated with the conducting polymers, PANI or PPy was in accordance to our previously reported method. The composite membranes were characterized by FT-IR, scanning electron microscopy, electrical conductivity measurements, I–V, mechanical tests, contact angle measurements, XRD and energy disperse spectroscopy. The novelty of the present work is the combination of electroconductive polymers, for the recovery of metals, and bromide as a leachate, less harmful than the traditionally used leachers.

The condensing effect and the ability of cholesterol (CHOL) to induce ordering in lipid films is a question of relevance in biological membranes such as the milk fat globule membrane (MFGM) in which the amount of CHOL influences the phase separation and mechanical resistance to rupture of coexisting phases relevant to emulsified food systems. Here, we study the effect of different salts (NaCl, CaCl2, MgCl2, LaCl3) on monolayers made of a model mixture of lipids (DPPC:DPPS 4:1) and CHOL. To this end, we apply Langmuir Film Balance to report a combined analysis of surface pressure-area (&pi, A) and surface potential-area (&Delta, V&ndash, A) isotherms along with Micro-Brewster Angle Microscopy (Micro-BAM) images of the monolayers in the presence of the different electrolytes. We show that the condensation of lipid by CHOL depends strongly on the nature of the ions by altering the shape and features of the &pi, A isotherms. &Delta, A isotherms provide further detail on the ion specific interactions with CHOL. Our results show that the condensation of lipids in the presence of CHOL depends on the combined action of ions and CHOL, which can alter the physical state of the monolayer.

Lowest-energy structures, the distribution of isomers, and their molecular properties depend significantly on geometry and temperature. Total energy computations using DFT methodology are typically carried out at a temperature of zero K, thereby, entropic contributions to the total energy are neglected, even though functional materials work at finite temperatures. In the present study, the probability of the occurrence of one particular Be4B8 isomer at temperature T is estimated by employing Gibbs free energy computed within the framework of quantum statistical mechanics and nanothermodynamics. To identify a list of all possible low-energy chiral and achiral structures, an exhaustive and efficient exploration of the potential/free energy surfaces is carried out using a multi-level multistep global genetic algorithm search coupled with DFT. In addition, we discuss the energetic ordering of structures computed at the DFT level against single-point energy calculations at the CCSD(T) level of theory. The total VCD/IR spectra as a function of temperature are computed using each isomer’s probability of occurrence in a Boltzmann-weighted superposition of each isomer’s spectrum. Additionally, we present chemical bonding analysis using the adaptive natural density partitioning method in the chiral putative global minimum. The transition state structures and the enantiomer–enantiomer and enantiomer–achiral activation energies as a function of temperature evidence that a change from an endergonic to an exergonic type of reaction occurs at a temperature of 739 K.

One of the major applications of Serum Albumins is their use as delivery systems for lipophilic compounds in biomedicine. Their biomedical application is based on the similarity with Human Serum Albumin (HSA), as a fully biocompatible protein. In general, Bovine Serum Albumin (BSA) is treated as comparable to its human homologue and used as a model protein for fundamental studies since it is available in high amounts and well understood. This protein can act as a carrier for lipophilic compounds or as protective shell in an emulsion-based vehicle. Polysaccharides are generally included in these formulations in order to increase the stability and/or applicability of the carrier. In this review, the main biomedical applications of Albumins as drug delivery systems are first presented. Secondly, the differences between BSA and HSA are highlighted, exploring the similarities and differences between these proteins and their interaction with polysaccharides, both in solution and adsorbed at interfaces. Finally, the use of Albumins as emulsifiers for emulsion-based delivery systems, concretely as Liquid Lipid Nanocapsules (LLNs), is revised and discussed in terms of the differences encountered in the molecular structure and in the interfacial properties. The specific case of Hyaluronic Acid is considered as a promising additive with important applications in biomedicine. The literature works are thoroughly discussed highlighting similarities and differences between BSA and HSA and their interaction with polysaccharides encountered at different structural levels, hence providing routes to control the optimal design of delivery systems.

The preparation of composites of cellulose acetate, triphenyl phosphate and poly (acrylic acid) (M), coated with polyaniline (M-PAni) or polypyrrole (M-PPy), including tests of the adsorptivity of complexes of copper-iodide, are presented in this work. Characterization of M-PAni and M-PPy by FT-IR and TGA before and after being exposed to natural weathering conditions are done to study the effects that environmental conditions have on them. In solutions with Cu only, the M-PAni presented 51.6% Cu adsorption and M-PPy presented 10.7%. SEM analysis, EDS, XPS and ATR-FTIR of M-PAni and M-PPy before and after of Cu adsorption are included. In the presence of gold-iodide complex, M-PAni shows 47.4% Cu adsorption, six times higher than the M-PPy, 7.2%; this result is attributed to better interaction between the PAni and the copper-iodide complex than PPy and the copper-iodide. The adsorption equilibrium data of copper-iodide complex fits the Langmuir isotherm model for both M-PAni and M-PPy, suggesting the formation of an adsorbed monolayer. Desorption process for Au is more effective in the two materials, 34.1% with M-PAni and 86.6% with M-PPy, than for Cu with 1.0% and 2.6% respectively. The present method, which uses iodide as a single leaching agent for Au and Cu and M-PAni and M-PPy as adsorbents is recommended. These composites are suitable selective materials.

Human serum albumin (HSA) has been shown to be an ideal protein for nanoparticle preparation. These are usually prepared by using cross linker agents such as glutaraldehyde (GAD). Liquid lipid nanocapsules (LLN) constitute a new generation of nanoparticles more biocompatible and versatile for oral delivery of lipophylic drugs. The first barrier that an orally administered formulation must cross is the gastrointestinal tract. Hence, it is crucial to address the impact of gastrointestinal digestion on these structures in order to achieve an optimal formulation. This study evaluates the effect of gastric digestion on HSA emulsions structured with GAD as a model substrate for the preparation of LLN. This is done by SDS-PAGE, emulsion microstructure, and interfacial tension techniques. Our results demonstrate that the cross- linking procedure with GAD strongly inhibits pepsin digestion by formation of inter- and/or intramolecular covalent bonds between substrate amino acids. Emulsification of HSA also protects from gastric digestion probably by the orientation of the HSA molecule, which exposes the majority of pepsin cleaving sites preferably to the hydrophobic part of the oil-water interface. In this emulsified HSA, cross-linking with GAD at the interface promotes structural modifications on the HSA interfacial layer, restricting the access of pepsin to cleavage sites. We identify interfacial aspects underlying enzymatic hydrolysis of the protein. Assuring that HSA-GAD structures resist passage through the gastric compartment is crucial is important towards the rational design of oral delivery systems and the first step to get the complete digestion profile.

The behaviour of proteins (β-lactoglobulin (βlg) and soy protein isolate (SPI)) and a surface active polysaccharide (hydroxypropylmethylcellulose, HPMC) o/w interfacial films under simulated gastrointestinal conditions using the interfacial tensiometer Octopus were compared and related to the performance of the emulsions (using the same emulsifiers) under in vitro digestion. The evolution of interfacial tension (γ) was used to investigate the effect of gastrointestinal fluids on o/w interfacial films. Clear differences were observed among these emulsifiers. During the gastric phase, HPMC showed the lowest change in γ values as compared to protein films. The most important changes occurred during the intestinal stage where it was observed an important decrease of γ associated with the rapid penetration of BS, followed by a lower rate of decrease attributable to the accumulation of FFA at the interface. In the last stage, the subphase was exchanged by buffer alone, to remove the reversibly adsorbed digestion products. SPI formed the most resistant interface to the remotion of digestion products, followed by HPMC and finally by βlg. The results agree with the degree of lipolysis reported for the emulsions stabilized by these emulsifiers, which suggest that lipid digestion could be modulated by the ability of emulsifiers to prevent the BS activity (to adsorb at the O/W interface or remove the inhibitory digestion products from the interface). Thus, emulsifiers-BS interactions appears as a key factor in controlling the lipolysis. Fil: Bellesi, Fernando Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; Argentina Fil: Pizones Ruiz Henestrosa, Víctor Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; Argentina Fil: Maldonado Valderrama, Julia. Universidad de Granada; España Fil: Del Castillo Santaella, Teresa. Universidad de Granada; España Fil: Pilosof, Ana Maria Renata. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Industrias; Argentina

Targeted delivery of therapeutics is an alternative approach for the selective treatment of infectious diseases. The surface of African trypanosomes, the causative agents of African trypanosomiasis, is covered by a surface coat consisting of a single variant surface glycoprotein, termed VSG. This coat is recycled by endocytosis at a very high speed, making the trypanosome surface an excellent target for the delivery of trypanocidal drugs. Here, we report the design of a drug nanocarrier based on poly ethylen glycol (PEG) covalently attached (PEGylated) to poly(D,L-lactide-co-glycolide acid) (PLGA) to generate PEGylated PLGA nanoparticles. This nanocarrier was coupled to a single domain heavy chain antibody fragment (nanobody) that specifically recognizes the surface of the protozoan pathogenTrypanosoma brucei. Nanoparticles were loaded with pentamidine, the first-line drug forT. b. gambienseacute infection. Anin vitroeffectiveness assay showed a 7-fold decrease in the half-inhibitory concentration (IC50) of the formulation relative to free drug. Furthermore,in vivotherapy using a murine model of African trypanosomiasis demonstrated that the formulation cured all infected mice at a 10-fold lower dose than the minimal full curative dose of free pentamidine and 60% of mice at a 100-fold lower dose. This nanocarrier has been designed with components approved for use in humans and loaded with a drug that is currently in use to treat the disease. Moreover, this flexible nanobody-based system can be adapted to load any compound, opening a range of new potential therapies with application to other diseases.

The electrical, mechanical, and piezoresistive properties of ternary composites based on elastomeric polydimethylsiloxane (PDMS), carbon nanotubes (CNTs), and polyaniline (PANI) were studied and compared with those of binary PDMS–CNT composites. The presence of PANI affected the percolating network of the CNTs. At lower PANI concentrations (2.5 and 5%), the conductive network of the CNTs was constructively modified; this led to an enhancement in the conductivity in the sample containing 2% CNTs. A higher PANI content (7.5%) hindered the flow of main charge carriers through the composite. The piezoresistive response of the binary and ternary composites was studied by cyclic experiments under compression loads. In all of the samples, the electrical resistance increased monotonically up to a 10% strain. The reproducibility of the piezoresistive behavior in the binary and ternary composites provided evidence that the fillers could reversibly recover their initial position together with the PDMS chains without a significant displacement with respect to their original positions. The reduction of the piezoresistive sensibility by PANI addition was attributed to the displacement restrictions of the CNTs within the composite under pressure because of the volume exclusion of PANI particles; this maintained the probability of CNT contact and increased the possibility of the formation of new CNT conductive channels. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44780.

The use of mixtures of synthetic and natural polymers is a potential option to reduce the pollution by plastic waste. In this work, the method for the chemical modification of chitosan with poly(lactic acid) was developed, then, the preparation of films of blends of polyethylene and chitosan-poly(lactic acid) produced by an extrusion method using polyethylene-graft maleic anhydride as a compatibilizer. It was possible to obtain films with a maximum content of 20 wt% and 30 wt%, chitosan, with and without compatibilizer, respectively. Scanning electron microscope (SEM) analysis showed a homogeneous surface on all films. The addition of the compatibilizer had a significant effect on the mechanical properties of the films, such as an increase in Young’s modulus and a decrease in the elongation at break, additionally, the compatibilizer promotes thermal degradation in a single step and gives the film a slight increase in thermal resistance. These results are attributed to an improved interaction in the interface of polyethylene and chitosan-poly(lactic acid), promoted by the compatibilizer.

Background: Myocardial injury after noncardiac surgery (MINS) was defined as prognostically relevant myocardial injury due to ischemia that occurs during or within 30 days after noncardiac surgery. The study’s four objectives were to determine the diagnostic criteria, characteristics, predictors, and 30-day outcomes of MINS. Methods: In this international, prospective cohort study of 15,065 patients aged 45 yr or older who underwent in-patient noncardiac surgery, troponin T was measured during the first 3 postoperative days. Patients with a troponin T level of 0.04 ng/ml or greater (elevated “abnormal” laboratory threshold) were assessed for ischemic features (i.e., ischemic symptoms and electrocardiography findings). Patients adjudicated as having a nonischemic troponin elevation (e.g., sepsis) were excluded. To establish diagnostic criteria for MINS, the authors used Cox regression analyses in which the dependent variable was 30-day mortality (260 deaths) and independent variables included preoperative variables, perioperative complications, and potential MINS diagnostic criteria. Results: An elevated troponin after noncardiac surgery, irrespective of the presence of an ischemic feature, independently predicted 30-day mortality. Therefore, the authors’ diagnostic criterion for MINS was a peak troponin T level of 0.03 ng/ml or greater judged due to myocardial ischemia. MINS was an independent predictor of 30-day mortality (adjusted hazard ratio, 3.87; 95% CI, 2.96–5.08) and had the highest population-attributable risk (34.0%, 95% CI, 26.6–41.5) of the perioperative complications. Twelve hundred patients (8.0%) suffered MINS, and 58.2% of these patients would not have fulfilled the universal definition of myocardial infarction. Only 15.8% of patients with MINS experienced an ischemic symptom. Conclusion: Among adults undergoing noncardiac surgery, MINS is common and associated with substantial mortality.

Modifying the protein conformation appears to improve the digestibility of proteins in the battle against allergies. However, it is important not to lose the protein functionality in the process. Light pulse technology has been recently tested as an efficient non-thermal process which alters the conformation of proteins while improving their functionality as stabilizers. Also, in order to rationally design emulsion based food products with specific digestion profiles, we need to understand how interfacial composition influences the digestion of coated interfaces. This study has been designed to investigate the effects of pulsed light (PL) treatment on the gastrointestinal digestion of protein covered interfaces. We have used a combination of dilatational and shear rheology which highlights inter and intra-molecular interactions providing new molecular details on protein digestibility. Thein vitrodigestion model analyses sequentially pepsinolysis, trypsinolysis and lipolysis of β-lactoglobulin (BLG) and pulsed light treated β-lactoglobulin (PL-BLG). The results show that the PL-treatment seems to facilitate digestibility of the protein network, especially regarding trypsinolysis. Firstly, PL treatment just barely enhances the enzymatic degradation of BLG by pepsin, which dilutes and weakens the interfacial layer, due to increased hydrophobicity of the protein owing to PL-treatment. Secondly, PL treatment importantly modifies the susceptibility of BLG to trypsin hydrolysis. While it dilutes the interfacial layer in all cases, it strengthens the BLG and weakens the PL-BLG interfacial layer. Finally, this weakening appears to slightly facilitate lipolysis as evidenced by the results obtained upon addition of lipase and bile salts (BS). This research allows identification of the interfacial mechanisms affecting enzymatic hydrolysis of proteins and lipolysis, which demonstrates an improved digestibility of PL-BLG. The fact that PL treatment did not affect the functionality of the protein makes it a valuable alternative for tailoring novel food matrices with improved functional properties such as decreased digestibility, controlled energy intake and low allergenicity.