Aqueous Two-Phase Systems: simple one-step process formulation and phase diagram for characterisation

Abstract

Aqueous two-phase system (ATPS), also called "water-in-water" emulsion, is a multicomponent system (aqueous droplets dispersed in a continuous aqueous phase), formed after gently mixing two aqueous solutions of immiscible polymers. It allows the formation of different compartments without adding any organic solvent, according to a green process. Nevertheless, the kinetic stability of ATPS is generally difficult to control. Phase diagrams, which express the concentration of a polymer as a function of that of the other in solution, are used to characterise ATPS and to determine conditions for preparing emulsions from selected polymers. In this study, dextran and polyethylene oxide aqueous mixtures with different processing parameters are investigated. Phase diagrams are generated through two automatic methods (Turbiscan and LUMiSizer® technologies) and a manual one. With the diagrams obtained, it is concluded that the purity of polyethylene oxide affects the ATPS, whereas the use of polymers in powder or in solution form has no effect. In view of this result, it is allowed to prepare ATPS formulation by a simple one-step process from polymers in powder form.

A new method to prepare microparticles based on an Aqueous Two-Phase system (ATPS), without organic solvents

“…ATPS characterization ATPS are usually characterized with phase diagrams, which express the concentration of one polymer as a function of the other, and show the binodal lines separating ATPS and no ATPS areas, as well as the tie-lines [30]. Based on our previous work, a dextran/PEO ATPS was formulated from polymers in powder form with purified PEO [13]. Fig.…”

“…Dumas et al [13] Copyright 2020, Colloid and Polymer Science. (ATPS: Aqueous Two-Phase System, PEO: polyethylene oxide).…”

“…Despite their widespread use, understanding the partition process involved in the formation of an ATPS remains a challenge [2,6]. Phase diagrams of ATPS formulated from dextran and PEO (a high molecular weight PEG) have been described in the literature, and the concentration conditions for ATPS formation have been determined [13,14]. The importance of using purified PEO (without silica impurities) has been highlighted, and the interest of using polymers in powder-form to allow a simple one-step process for ATPS formulation was demonstrated [13].…”

Application of Aqueous Two-Phase Systems in the Extraction of Bovine Serum Albumin

“…The appropriate pH 9 value was used to create the phosphate stock solution. ATPS of the PEG/Dextran system were prepared based on binodal curves [24,25]. PH value for the prepared system was 7.…”

“…A syringe was used to properly separate the phases once phase equilibrium had been reached. The bottom phases' volumes were finally calculated, and samples were collected for protein concentration analysis [15,24,26,27].…”