Preparation of Phase Systems and Measurement of Their Physicochemical Properties

Bamberger, Stephan

doi:10.1016/b978-0-12-733860-6.50010-4

Cited by 39 publications

(36 citation statements)

References 63 publications

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“…This can be obtained from previous reports or can be constructed using the cloud point method. 23 In polymer (PEG)-salt ATPS, to facilitate further product separation, conditions are pursued that promote concentration of the product of interest in the top phase (PEG-rich phase) and the contaminants (including cells and cell debris) in the bottom phase (salt-rich phase) or interface.…”

Section: 22mentioning

confidence: 99%

Practical experiences from the development of aqueous two‐phase processes for the recovery of high value biological products

Benavides

Rito‐Palomares

2007

J of Chemical Tech & Biotech

142

122

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The development of recovery processes using aqueous two-phase systems (ATPS) has been limited by the extensive experimental work required to establish the optimal system parameters to ensure selective partitioning of the product of interest. Although using full factorial experiments has been demonstrated to be an effective strategy for the characterization of the partitioning behaviour of biological products in ATPS, this approach is characterized by its costly and time consuming nature. As an alternative, the use of a robotic-aided strategy has been proposed. However, the need for high cost equipment may limit the generic implementation of this strategy. Based on practical experience using ATPS, practical strategies for the predictive design of primary recovery processes using polymer-salt systems were derived. To evaluate the generic application of the proposed strategies, four experimental models (B-phycoerythrin, C-phycocyanin, double layered rotavirus-like particles and lutein) were selected. The application of these strategies resulted in the development of simplified recovery processes for the selected experimental models. The practical review presented is considered a relevant contribution that will provide general rules to facilitate the establishment of ATPS processes, particularly for new researchers in the field.

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Section: 22mentioning

confidence: 99%

Practical experiences from the development of aqueous two‐phase processes for the recovery of high value biological products

Benavides

Rito‐Palomares

2007

J of Chemical Tech & Biotech

142

122

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“…PEG forms aqueous two‐phase systems with several polymers including polysaccharides, such as dextran, methylcellulose, and hyaluronate 25, 26. Phase separation of the two polymers depends on the composition of the polymers and the solvent.…”

Section: Discussionmentioning

confidence: 99%

Adhesion barriers of carboxymethylcellulose and polyethylene oxide composite gels

Liu

Berg

2002

J. Biomed. Mater. Res.

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Composite gels and films of CMC and PEO have been used to separate healing tissues and have been demonstrated to reduce postsurgical adhesions in animal models of adhesion formation. Gels of CMC/PEO were studied here to elucidate the mechanism by which the combination of PEO with CMC is effective in reducing adhesions between tissues. CMC and PEO were demonstrated to undergo micro phase separation to form a two-phase system. Protein partitioning was measured in this system for albumin, fibrinogen, and gamma globulin. All of these proteins were found to partition preferentially into the CMC phase. When gels of CMC and PEO were examined for tissue adherence, the addition of PEO reduced the adherence of CMC to tissues. To further investigate the effects of PEO on tissue adherence of the gel, the extent of thrombus formation of citrated blood initiated by calcium chloride in CMC/PEO gels was measured in vitro. The extent of thrombus formation by CMC was reduced proportionally to the content of PEO in gels of CMC/PEO. A model was developed to explain how CMC and PEO contribute to the effectiveness of CMC/PEO gels that form a barrier between healing tissues to reduce postsurgical adhesions. In an open system PEO is released from the gel faster than CMC is dissolved, resulting in a shell structure with CMC coated by PEO. The PEO-rich outer layer functions to inhibit protein deposition and thrombus formation. The CMC-rich layer functions to anchor the gel to the tissue surface.

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“…The results are summarized in Table 2. When the electrophoresis temperature was lower than the equil- ibration temperature, separation of the phases was more rapid, because when the temperature was lowered the equilibrium composition of the phases (tie line length and slope) was disturbed (13). The PEG content increased in the PEG-rich phase and the MDX content in the lower phase remained essentially the same, while the total composition remained unchanged.…”

Section: Effect Of Phase Equilibration Temperaturementioning

confidence: 97%

Electrokinetic Demixing of Two-Phase Aqueous Polymer Systems. II. Separation Rates of Polyethylene Glycol–Maltodextrin Mixtures

Rao

Stewart

Todd

1991

Separation Science and Technology

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Aqueous two-phase extraction techniques have been successfully applied to the purification of enzymes and cells. However, due to their similar physical properties, immiscible aqueous phases do not separate rapidly. A method for enhanced demixing of aqueous two-phase systems in a thermostated vertical electrophoresis column was therefore studied. The effects of the electric field strength, field polarity, temperature, phase composition, and buffer concentration on demixing rates of a polyethylene glycol-maltodextrin (PEG-MDX) system were quantitatively measured. At normal electrical polarity (anode at the top of the column), using a maximum practicable field strength of 26.4 V/cm, the demixing rate was twice that in zero electric field at 25 2 2°C. With polarity reversed (anode at the bottom, electric field opposing gravitational settling) at a field of 26.4 V/cm, demixing was 5.5 times as fast as in zero field. Reduction of the temperature from 25 to 14°C caused an increase in demixing rate in the absence of an applied field, while reduced temperature did not change the rate when using electric fields of either normal or reverse polarity. Increased phosphate buffer concentration substantially increased the demixing rate for PEG-MDX mixtures.

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Preparation of Phase Systems and Measurement of Their Physicochemical Properties

Cited by 39 publications

References 63 publications

Practical experiences from the development of aqueous two‐phase processes for the recovery of high value biological products

Practical experiences from the development of aqueous two‐phase processes for the recovery of high value biological products

Adhesion barriers of carboxymethylcellulose and polyethylene oxide composite gels

Electrokinetic Demixing of Two-Phase Aqueous Polymer Systems. II. Separation Rates of Polyethylene Glycol–Maltodextrin Mixtures

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