Influence of tie line length and volume ratio on the partition behavior of peripheral blood and conjugated CD34 antibody in polymer-polymer aqueous two-phase systems

Abstract

Aqueous two-phase systems (ATPS) offer great opportunities regarding the purification of stem cells for future medical applications. However, most publications exploring the use of ATPS for the biopurification of stem cells are focused only on the use of a single system or in the comparison of different kinds of systems. These studies do not consider the influence of the parameters of the system on the partition behavior of the biomolecules. Therefore, in the presented work, the influence of the intrinsic parameters tie line length (TLL) and volume ratio (VR) on the partition behavior of human peripheral blood and a fluorescent-labeled CD34 antibody in three different ATPS [PEG (polyethylene glycol) 8000–Dextran 500,000, Ficoll 400,000–Dextran 70,000 and UCON (50-HB-5100)–Dextran 75,000] are investigated. In the PEG-Dextran and UCON-Dextran systems, the blood separation is independent from the two parameters, whereas in the Ficoll-Dextran system, high VR shifts the partition to the top phase. For the conjugated CD34 antibody, higher VR and lower TLL shift the partition behavior to the top phase in all systems. Furthermore, the results propose that VR has a stronger effect on the separation behavior than TLL. These results suggested that both, TLL and VR variations, can be exploited to improve the purification of bioproducts such as stem cells.