Protein Separation via Polyelectrolyte Coacervation: Selectivity and Efficiency

Wang, Yingfan; Gao, Jeff Y.; Dubin, Paul L.

doi:10.1021/bp960013+

Cited by 166 publications

(141 citation statements)

References 22 publications

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“…This number of BSA molecules per PDADMAC chain agrees with results obtained under comparable conditions by spectroscopic estimation of BSA concentrations in the centrifuged upper layer separated from the coacervate phase. 22 In the pH range 6-10, the charge on BSA, Z , is given empirically as Z ) 26.4-6.0 pH. 10,23 In the case of r ) 10 and 100 mM NaCl, it can be estimated from pH φ ) 6.8 that Z ) -14.…”

Section: Resultsmentioning

confidence: 99%

pH-Induced Coacervation in Complexes of Bovine Serum Albumin and Cationic Polyelectrolytes

et al. 2000

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Turbidity and light scattering measurements, along with phase contrast microscopy, were used to follow the processes leading to coacervation when aqueous solutions of bovine serum albumin (BSA) and poly-(dimethyldiallylammonium chloride) (PDADMAC) were brought from pH ) 4 to 10. The state of macromolecular assembly of complexes formed between BSA and PDADMAC prior to and during the pH-induced coacervation could be characterized by specific pH values at which recognizable transitions took place. In addition to the two characteristic pH values (pH crit and pH φ ) previously identified through turbidimetry, other transitions were explicitly established. On the basis of the pH-induced evolution of scattering intensity measurements, we concluded that the formation of soluble primary protein-polymer complexes is initiated at pH crit and proceeds until "pH′ crit ". A subsequent increase in scattering intensity at "pH pre " may arise from the assembly of quasi-neutralized primary complexes as their net positive charge decreases with increase in pH. Subsequently, a maximum in scattering intensity at pH φ is observed coincident with the appearance of turbidity and also corresponding to the first microscopic observation of coacervate droplets. The temperature independence of pH crit and pH φ suggests that hydrophobic contributions are negligible for the initial BSA-PDADMAC interactions and the subsequent coacervation process. The pH dependence of scattering intensity profiles allowed the identification of two other transitions beyond pH φ . Spherical microcoacervate droplets first observed around pH φ subsequently displayed morphological changes at "pH morph ", followed by the transformation to solid or flocculant substances at pH precip.

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Section: Resultsmentioning

confidence: 99%

pH-Induced Coacervation in Complexes of Bovine Serum Albumin and Cationic Polyelectrolytes

et al. 2000

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“…14 Second, polyelectrolyte coacervation can be used to separate proteins, even those with similar pI. 15 Third, the preservation of enzyme activity in 20-25% enzyme-loaded coacervate droplets 16 points to their use as enzyme microreactors. 17 These considerations motivate a deeper understanding of both the mechanism of protein-PE coacervation and the nature of the coacervates.…”

Section: Introductionmentioning

confidence: 99%

Mesophase separation and probe dynamics in protein–polyelectrolyte coacervates

et al. 2007

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Protein-polyelectrolyte coacervates are self-assembling macroscopically monophasic biomacromolecular fluids whose unique properties arise from transient heterogeneities. The structures of coacervates formed at different conditions of pH and ionic strength from poly(dimethyldiallylammonium chloride) and bovine serum albumin (BSA), were probed using fluorescence recovery after photobleaching. Measurements of self-diffusion in coacervates were carried out using fluorescein-tagged BSA, and similarly tagged Ficoll, a non-interacting branched polysaccharide with the same size as BSA. The results are best explained by temporal and spatial heterogeneities, also inferred from static light scattering and cryo-TEM, which indicate heterogeneous scattering centers of several hundred nm. Taken together with previous dynamic light scattering and rheology studies, the results are consistent with the presence of extensive dilute domains in which are embedded partially interconnected 50-700 nm dense domains. At short length scales, protein mobility is unobstructed by these clusters. At intermediate length scales, proteins are slowed down due to tortuosity effects within the blind alleys of the dense domains, and to adsorption at dense/dilute domain interfaces. Finally, at long length scales, obstructed diffusion is alleviated by the break-up of dense domains. These findings are discussed in terms of previously suggested models for protein-polyelectrolyte coacervates. Possible explanations for the origin of mesophase separation are offered.

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“…On the other hand, complexation has been studied in the purification and recovery of the macromolecules (e.g. protein) [11] and in the development of food ingredients, such as fat substitutes and meat replacers [12]. The studies on film formation properties of the coacervate complexes of sodium caseinate/wheat or starch corn have displayed that coacervate films are also promising in the fields of biopackaging or edible food packaging as they represent good mechanical and gas barrier properties [13].…”

Section: Introductionmentioning

confidence: 99%

Complex coacervation of silk fibroin and hyaluronic acid

Malay

Bayraktar

Batıgün

2007

International Journal of Biological Macromolecules

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This study aimed to investigate the pH-induced complexation of silk fibroin (SF) and hyaluronic acid (HA). SF-HA complex coacervation was investigated by monitoring turbidity of the SF-HA system under slow acidification. Gravimetric analysis was performed to determine the yield of complex coacervation and viscosity of the system was measured to study the formation of the complexes at different pH values. The influences of total biopolymer concentration and biopolymer weight ratio on complex coacervation were examined during the analyses. Formation of the complexes was evidenced by the minimum viscosity and the maximum turbidity observed in the system. SF-HA complexes were formed within the pH-window of 2.5-3.5 regardless of the total biopolymer concentration or biopolymer ratio. Complex coacervation of SF-HA showed a reversible behavior and coacervation could be handled even in excess amounts of the biopolymers, which pointed out a non-stoichiometric complexation.

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Protein Separation via Polyelectrolyte Coacervation: Selectivity and Efficiency

Cited by 166 publications

References 22 publications

pH-Induced Coacervation in Complexes of Bovine Serum Albumin and Cationic Polyelectrolytes

pH-Induced Coacervation in Complexes of Bovine Serum Albumin and Cationic Polyelectrolytes

Mesophase separation and probe dynamics in protein–polyelectrolyte coacervates

Complex coacervation of silk fibroin and hyaluronic acid

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