Generation of polyethylene glycol-dextran aqueous two-phase system droplets using different culture media under in vitro conditions

Aqueous two-phase systems (ATPS) involve the combination of two immiscible polymers that at certain concentrations form a biphasic separation system. Due to the physico-chemical properties and the low interfacial tension of the ATPS-forming polymers, the generation of ATPS droplets began to be explored. This work aims to characterize the generation of ATPS droplets evaluating four polyethylene glycol (PEG)-dextran (DEX) systems (combinations of molecular weights and concentrations) using Essential 8 (Gibco), DMEM-F12 (Gibco), StemLine II (Sigma-Aldrich), MSCs Basal (ATCC), RPMI 1640 (Gibco), and NutriStem (Sartorius) as ATPS solvents under in vitro conditions. In 96 well-plates, one DEX droplet of 1 liL was immersed at the bottom of the well filled with 50 liL of PEG bulk phase. ATPS droplets were generated in all tested PEG-DEX systems showing circular morphology with a mid-range diameter size in the six-culture media of 1.30 +/- 0.18 mm, 1.30 +/- 0.22 mm, 1.30 +/- 0.43 mm, 1.21 +/- 0.27 mm, 1.20 +/- 0.16 mm, and 1.07 +/- 0.21 mm, respectively. Uniformity was susceptible to the culture media composition showing a coefficient of variation range of 0.64-12.40 % among the four studied PEG-DEX systems. By controlling the geometry of ATPS droplets, specific cell patterns can be determined for the further construction of different cell microenvironments in 3D cultures using ATPS.(c) 2023 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study aims to characterize the generation of ATPS droplets by evaluating four PEG-DEX systems under in vitro conditions. Using different culture media as ATPS solvents, ATPS droplets were successfully generated with varying sizes. The diameter of the ATPS droplets ranged from 1.07 mm to 1.30 mm depending on the culture media composition.