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Charles E. Sing - One of the best experts on this subject based on the ideXlab platform.
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Correction: Transfer matrix theory of polymer Complex Coacervation.
Soft matter, 2019Co-Authors: Tyler K. Lytle, Charles E. SingAbstract:Correction for ‘Transfer matrix theory of polymer Complex Coacervation’ by Tyler K. Lytle et al., Soft Matter, 2017, 13, 7001–7012.
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transfer matrix theory of polymer Complex Coacervation
Soft Matter, 2017Co-Authors: Tyler K. Lytle, Charles E. SingAbstract:Oppositely charged polyelectrolytes can undergo a macroscopic, associative phase separation in solution, via a process known as Complex Coacervation. Significant recent effort has gone into providing a clear, physical picture of Coacervation; most work has focused on improving the field theory picture that emerged from the classical Voorn–Overbeek theory. These methods have persistent issues, however, resolving the molecular features that have been shown to play a major role in coacervate thermodynamics. In this paper, we outline a theoretical approach to Coacervation based on a transfer matrix formalism that is an alternative to traditional field-based approaches. We develop theoretical arguments informed by experimental observation and simulation, which serve to establish an analytical expression for polymeric Complex Coacervation that is consistent with the molecular features of coacervate phases. The analytical expression provided by this theory is in a form that can be incorporated into more complicated theoretical or simulation formalisms, and thus provides a starting point for understanding coacervate-driven self-assembly or biophysics.
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Development of the modern theory of polymeric Complex Coacervation.
Advances in colloid and interface science, 2016Co-Authors: Charles E. SingAbstract:Oppositely charged polymers can undergo the process of Complex Coacervation, which refers to a liquid-liquid phase separation driven by electrostatic attraction. These materials have demonstrated considerable promise as the basis for Complex, self-assembled materials. In this review, we provide a broad overview of the theoretical tools used to understand the physical properties of polymeric coacervates. In particular, we discuss historic theories (Voorn-Overbeek, Random Phase Approximation), and then describe recent developments in the field (Field Theoretic, Counterion Release, Molecular Simulation, and Polymer Reference Interaction Site Model methods). We provide context for these methods, and map out the patchwork of theoretical models that are used to describe a diverse array of coacervate systems. We use this review of the literature to clarify a number of important theoretical challenges remaining in our physical understanding of Complex Coacervation.
Christine D Keating - One of the best experts on this subject based on the ideXlab platform.
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phosphorylation mediated rna peptide Complex Coacervation as a model for intracellular liquid organelles
Nature Chemistry, 2016Co-Authors: William M Aumiller, Christine D KeatingAbstract:Biological cells are highly organized, with numerous subcellular compartments. Phosphorylation has been hypothesized as a means to control the assembly/disassembly of liquid-like RNA- and protein-rich intracellular bodies, or liquid organelles, that lack delimiting membranes. Here, we demonstrate that charge-mediated phase separation, or Complex Coacervation, of RNAs with cationic peptides can generate simple model liquid organelles capable of reversibly compartmentalizing biomolecules. Formation and dissolution of these liquid bodies was controlled by changes in peptide phosphorylation state using a kinase/phosphatase enzyme pair. The droplet-generating phase transition responded to modification of even a single serine residue. Electrostatic interactions between the short cationic peptides and the much longer polyanionic RNAs drove phase separation. Coacervates were also formed on silica beads, a primitive model for localization at specific intracellular sites. This work supports phosphoregulation of Complex Coacervation as a viable mechanism for dynamic intracellular compartmentalization in membraneless organelles.
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Phosphorylation-mediated RNA/peptide Complex Coacervation as a model for intracellular liquid organelles
Nature Chemistry, 2016Co-Authors: William M Aumiller, Christine D KeatingAbstract:Biological cells are highly organized, with numerous subcellular compartments. Phosphorylation has been hypothesized as a means to control the assembly/disassembly of liquid-like RNA- and protein-rich intracellular bodies, or liquid organelles, that lack delimiting membranes. Here, we demonstrate that charge-mediated phase separation, or Complex Coacervation, of RNAs with cationic peptides can generate simple model liquid organelles capable of reversibly compartmentalizing biomolecules. Formation and dissolution of these liquid bodies was controlled by changes in peptide phosphorylation state using a kinase/phosphatase enzyme pair. The droplet-generating phase transition responded to modification of even a single serine residue. Electrostatic interactions between the short cationic peptides and the much longer polyanionic RNAs drove phase separation. Coacervates were also formed on silica beads, a primitive model for localization at specific intracellular sites. This work supports phosphoregulation of Complex Coacervation as a viable mechanism for dynamic intracellular compartmentalization in membraneless organelles. Intracellular bodies called liquid organelles are rich in nucleic acids and proteins, and are thought to occur by liquid–liquid phase coexistence. Now, enzymatic control over the phosphorylation state of a simple cationic peptide, thereby altering its electrostatic interaction with RNA, has been shown to drive formation and dissolution of droplets that mimic these intracellular liquid bodies.
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Phosphorylation-mediated RNA/peptide Complex Coacervation as a model for intracellular liquid organelles.
Nature chemistry, 2015Co-Authors: William M Aumiller, Christine D KeatingAbstract:Biological cells are highly organized, with numerous subcellular compartments. Phosphorylation has been hypothesized as a means to control the assembly/disassembly of liquid-like RNA- and protein-rich intracellular bodies, or liquid organelles, that lack delimiting membranes. Here, we demonstrate that charge-mediated phase separation, or Complex Coacervation, of RNAs with cationic peptides can generate simple model liquid organelles capable of reversibly compartmentalizing biomolecules. Formation and dissolution of these liquid bodies was controlled by changes in peptide phosphorylation state using a kinase/phosphatase enzyme pair. The droplet-generating phase transition responded to modification of even a single serine residue. Electrostatic interactions between the short cationic peptides and the much longer polyanionic RNAs drove phase separation. Coacervates were also formed on silica beads, a primitive model for localization at specific intracellular sites. This work supports phosphoregulation of Complex Coacervation as a viable mechanism for dynamic intracellular compartmentalization in membraneless organelles.
Marcelo Thomazini - One of the best experts on this subject based on the ideXlab platform.
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microencapsulation of ascorbic acid by Complex Coacervation protection and controlled release
Food Research International, 2013Co-Authors: Talita A Comunian, Marcelo Thomazini, Ana Julia Gouvea Alves, Fernando Eustaquio De Matos, Julio Cesar De Carvalho Balieiro, Carmen Silvia FavarotrindadeAbstract:Abstract Ascorbic acid (AA) is an efficient antioxidant that exhibits vitamin function but is naturally unstable. To overcome this problem, the objective of the present study was to improve AA microencapsulation by Complex Coacervation using both gelatin and gum arabic as encapsulating agents. To make the Coacervation of a hydrophilic core material viable, a water-in-oil emulsion was first prepared using corn oil, a 30% solution of AA and polyglycerol polyricinoleate (PGPR 90), as the surfactant. Nine microcapsule formulations were prepared containing gelatin, gum arabic and AA at ratios of 1:1:0.5, 1:1:0.75 and 1:1:1, with 0.025, 0.05 and 0.075 g/mL of the polymer, respectively. The morphology of the freeze-dried microcapsules was analyzed by optical microscopy and scanning electronic microscopy. The water activity, hygroscopicity, solubility, particle size, encapsulation efficiency, Fourier transform infrared spectroscopy and stability of the encapsulated material were also examined. All of the microcapsule formulations were spherical, multinucleate and only slightly soluble and hygroscopic. The encapsulation efficiency was high (approximately 98%); therefore, it was possible to efficiently encapsulate AA using the double emulsion method followed by Complex Coacervation. The ascorbic acid was protected and more stable in the microcapsule than in solution, which suggests the possibility of controlled release under specific conditions and masking the acidic taste of AA.
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microencapsulation of propolis extract by Complex Coacervation
Lwt - Food Science and Technology, 2011Co-Authors: Mirian Pozippe Nori, Carmen Silvia Favarotrindade, Marcelo Thomazini, Severino Matias De Alencar, Julio C De Camargo Balieiro, Carmen Josefina Contreras CastilloAbstract:Abstract The propolis has potential to be a natural food additive. However, its application is limited, because it is alcohol-soluble and has strong flavour. Microencapsulation may be an alternative for reducing these problems. The aim of this study was to encapsulate propolis extract by Complex Coacervation using isolated soy protein and pectin as encapsulant agents. The Coacervation was studied as a function of pH (5.0, 4.5, 4.0 and 3.5) and the concentration of encapsulants and core (2.5 and 5.0 g/100 mL). Samples obtained at pH 4.0 in both concentrations were lyophilized and analyzed for hygroscopicity, encapsulation efficiency, particle size, morphology, thermal behavior, stability of phenolic and flavonoids during storage, as well as antioxidant and antimicrobial activities. It was possible to encapsulate propolis extract by Complex Coacervation and to obtain it in the form of powder, alcohol-free, stable, with antioxidant property, antimicrobial activity against Staphylococcus aureus and with the possibility of controlled release in foods.
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microencapsulation of casein hydrolysate by Complex Coacervation with spi pectin
Food Research International, 2009Co-Authors: Debora V Mendanha, Sara Molina E Ortiz, Carmen Silvia Favarotrindade, Adriana N Mauri, Edneli Soraya Monterreyquintero, Marcelo ThomaziniAbstract:The aim of this work was to encapsulate casein hydrolysate by Complex Coacervation with soybean protein isolate (SPI)/pectin. Three treatments were studied with wall material to core ratio of 1:1, 1:2 and 1:3. The samples were evaluated for morphological characteristics, moisture, hygroscopicity, solubility, hydrophobicity, surface tension, encapsulation efficiency and bitter taste with a trained sensory panel using a paired comparison test. The samples were very stable in cold water. The hydrophobicity decreased inversely with the hydrolysate content in the microcapsule. Encapsulated samples had lower hygroscopicity values than free hydrolysate. The encapsulation efficiency varied from 91.62% to 78.8%. Encapsulated samples had similar surface tension, higher values than free hydrolysate. The results of the sensory panel test considering the encapsulated samples less bitter (P < 0.05) than the free hydrolysate, showed that Complex Coacervation with SPI/pectin as wall material was an efficient method for microencapsulation and attenuation of the bitter taste of the hydrolysate.
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Microencapsulation of casein hydrolysate by Complex Coacervation with SPI/pectin
Food Research International, 2009Co-Authors: Debora V Mendanha, Adriana N Mauri, Sara E. Molina Ortiz, Carmen Silvia Fávaro-trindade, Edneli Soraya Monterrey-quintero, Marcelo ThomaziniAbstract:The aim of this work was to encapsulate casein hydrolysate by Complex Coacervation with soybean protein isolate (SPI)/pectin. Three treatments were studied with wall material to core ratio of 1:1, 1:2 and 1:3. The samples were evaluated for morphological characteristics, moisture, hygroscopicity, solubility, hydrophobicity, surface tension, encapsulation efficiency and bitter taste with a trained sensory panel using a paired comparison test. The samples were very stable in cold water. The hydrophobicity decreased inversely with the hydrolysate content in the microcapsule. Encapsulated samples had lower hygroscopicity values than free hydrolysate. The encapsulation efficiency varied from 91.62% to 78.8%. Encapsulated samples had similar surface tension, higher values than free hydrolysate. The results of the sensory panel test considering the encapsulated samples less bitter (P < 0.05) than the free hydrolysate, showed that Complex Coacervation with SPI/pectin as wall material was an efficient method for microencapsulation and attenuation of the bitter taste of the hydrolysate.
Tyler K. Lytle - One of the best experts on this subject based on the ideXlab platform.
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Correction: Transfer matrix theory of polymer Complex Coacervation.
Soft matter, 2019Co-Authors: Tyler K. Lytle, Charles E. SingAbstract:Correction for ‘Transfer matrix theory of polymer Complex Coacervation’ by Tyler K. Lytle et al., Soft Matter, 2017, 13, 7001–7012.
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transfer matrix theory of polymer Complex Coacervation
Soft Matter, 2017Co-Authors: Tyler K. Lytle, Charles E. SingAbstract:Oppositely charged polyelectrolytes can undergo a macroscopic, associative phase separation in solution, via a process known as Complex Coacervation. Significant recent effort has gone into providing a clear, physical picture of Coacervation; most work has focused on improving the field theory picture that emerged from the classical Voorn–Overbeek theory. These methods have persistent issues, however, resolving the molecular features that have been shown to play a major role in coacervate thermodynamics. In this paper, we outline a theoretical approach to Coacervation based on a transfer matrix formalism that is an alternative to traditional field-based approaches. We develop theoretical arguments informed by experimental observation and simulation, which serve to establish an analytical expression for polymeric Complex Coacervation that is consistent with the molecular features of coacervate phases. The analytical expression provided by this theory is in a form that can be incorporated into more complicated theoretical or simulation formalisms, and thus provides a starting point for understanding coacervate-driven self-assembly or biophysics.
Benu Adhikari - One of the best experts on this subject based on the ideXlab platform.
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Complex Coacervation: Principles, mechanisms and applications in microencapsulation
International journal of biological macromolecules, 2018Co-Authors: Yakindra Prasad Timilsena, Benu Adhikari, Taiwo O. Akanbi, Nauman Khalid, Colin J BarrowAbstract:Complex Coacervation is a highly promising microencapsulation technique that is extensively employed in pharmaceutical, food, agriculture and textile industries. The process involves the interaction of oppositely charged polyelectrolytes in aqueous form. High payload and high encapsulation efficiency (up to 99%), relatively lower cost of processing, ability to use food-grade shell materials and synthesis at ambient temperature makes Coacervation an appropriate choice in food and agrochemical industries. Various works have been documented using different polymer systems and core-shell combinations. This review paper intends to summarize some of the recent advances in Complex Coacervation for use in the food and agriculture areas. Current status and future trends of plant proteins utilization for Complex Coacervation have been reviewed. It is expected that this review will be a useful resource for material scientists, food technologists and food engineers.
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Recent advances in the microencapsulation of omega-3 oil and probiotic bacteria through Complex Coacervation: A review
Trends in Food Science & Technology, 2018Co-Authors: Divya Eratte, Colin J Barrow, Kim Dowling, Benu AdhikariAbstract:Abstract Background Functional foods are a fastest growing sector of the food industry. The development of functional foods comprising omega-3 fatty acids and probiotic bacteria, through Complex Coacervation process is an emerging area of research and product development. Scope and approach We reviewed relevant literature concerning the use of Complex Coacervation in microencapsulation, focusing primarily on the inclusion of probiotic bacteria and omega-3 oils into a single delivery format. This review covers advantages and disadvantages of the Complex Coacervation process to microencapsulate bioactive ingredients, viability of probiotic bacteria and oxidative stability of omega-3 oil during the Complex Coacervation process, the bioaccessibility of omega-3 oil and probiotic bacteria during simulated gastrointestinal conditions and in-vivo testings. Key findings and conclusions The review describes the advantages of co-encapsulation using Complex Coacervation followed by spray drying. It also describes the technological hurdles that need to be resolved for further development of industrial applications of co-encapsulation of probiotic bacteria and omega-3 lipids. The co-encapsulation concept has been widely used in pharmaceutical delivery systems, but is a relatively new concept in food ingredient stabilisation and delivery. There is a commercial need of co-encapsulation of multiple bioactive ingredients within a single microcapsules, due to decreased cost and enhanced product quality. Complex Coacervation has been shown to be a useful method for the co-encapsulation of multiple unstable bioactive ingredients. Although in-vitro evaluation deliver useful bioavailability information, additional in-vivo and clinical trials are needed to determine the efficacy of bioactive release, particularly for microcapsules containing multiple bioactive ingredients.
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Optimisation of the Complex Coacervation between canola protein isolate and chitosan
Journal of Food Engineering, 2016Co-Authors: Peg Gee Chang, Yakindra Prasad Timilsena, Rahul K. Gupta, Benu AdhikariAbstract:Abstract The Complex Coacervation phenomenon between canola protein isolate (CPI) and chitosan (CS) was studied. CPI was extracted in the laboratory from canola meal and used in this study. The factors affecting the yield of CPI-chitosan Complex coacervates such as CPI-to-chitosan ratio, pH and strength of the electrostatic interaction (SEI) were investigated. The thermal characteristics of the un-cross-linked and transglutaminase cross-linked Complex coacervates were also determined. The optimum Complex Coacervation between CPI and CS occurred at the CPI-to-chitosan mass ratio of 16 and the pH range of 5.8–6.2. The peak denaturation temperature and the denaturation enthalpy of CPI in CPI-chitosan Complex were higher than those of the uncompleted or free CPI indicating that the Complexation made the CPI more thermally stable. The thermal stability of the coacervates was further enhanced when cross-linked with transglutaminase. The increased thermal stability of CPI in CPI-chitosan coacervate indicated that CPI-chitosan coacervates would be suitable for encapsulation of thermally sensitive food and pharmaceutical ingredients.
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Complex Coacervation between flaxseed protein isolate and flaxseed gum
Food Research International, 2015Co-Authors: Pratibha Kaushik, Colin J Barrow, Kim Dowling, Benu AdhikariAbstract:Abstract Flaxseed protein isolate (FPI) and flaxseed gum (FG) were extracted, and the electrostatic Complexation between these two biopolymers was studied as a function of pH and FPI-to-FG ratio using turbidimetric and electrophoretic mobility (zeta potential) tests. The zeta potential values of FPI, FG, and their mixtures at the FPI-to-FG ratios of 1:1, 3:1, 5:1, 10:1, 15:1 were measured over a pH range 8.0–1.5. The alteration of the secondary structure of FPI as a function of pH was studied using circular dichroism. The proportion of ɑ-helical structure decreased, whereas both β-sheet structure and random coil structure increased with the lowering of pH from 8.0 to 3.0. The acidic pH affected the secondary structure of FPI and the unfolding of helix conformation facilitated the Complexation of FPI with FG. The optimum FPI-to-FG ratio for Complex Coacervation was found to be 3:1. The critical pH values associated with the formation of soluble (pHc) and insoluble (pHɸ1) Complexes at the optimum FPI-to-FG ratio were found to be 6.0 and 4.5, respectively. The optimum pH (pHopt) for the optimum Complex Coacervation was 3.1. The instability and dissolution of FPI–FG Complex coacervates started (pHɸ2) at pH 2.1. These findings contribute to the development of FPI–FG Complex coacervates as delivery vehicles for unstable albeit valuable nutrients such as omega-3 fatty acids.
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optimisation of the microencapsulation of tuna oil in gelatin sodium hexametaphosphate using Complex Coacervation
Food Chemistry, 2014Co-Authors: Bo Wang, Benu Adhikari, Colin J BarrowAbstract:Abstract The microencapsulation of tuna oil in gelatin–sodium hexametaphosphate (SHMP) using Complex Coacervation was optimised for the stabilisation of omega-3 oils, for use as a functional food ingredient. Firstly, oil stability was optimised by comparing the accelerated stability of tuna oil in the presence of various commercial antioxidants, using a Rancimat™. Then zeta-potential (mV), turbidity and coacervate yield (%) were measured and optimised for Complex Coacervation. The highest yield of Complex coacervate was obtained at pH 4.7 and at a gelatin to SHMP ratio of 15:1. Multi-core microcapsules were formed when the mixed microencapsulation system was cooled to 5 °C at a rate of 12 °C/h. Crosslinking with transglutaminase followed by freeze drying resulted in a dried powder with an encapsulation efficiency of 99.82% and a payload of 52.56%. Some 98.56% of the oil was successfully microencapsulated and accelerated stability using a Rancimat™ showed stability more than double that of non-encapsulated oil.