Among them, emulsion, precipitation, spray drying, and dialysis methods are the most frequently used methods for the formation of particles 19, 24, 25, 26. Several methods have been used to develop PLGA nano and micro particles over the last several decades 19, 20, 21, 22, 23. Here, we take advantage of the tunable behavior of Pluronic F127 together with its ATPS system formation capability to produce PLGA particles with combinations of desirable properties that are difficult to integrate into a single particle otherwise. Further, Pluronic F127 has a LCST around physiological temperatures, and has been shown to form various self-assembling structures for use in template-directed synthesis of organic and inorganic structures 17, 18. Among the thermoresponsive polymers, Pluronic F127 has been widely used in biomedical applications 15, 16. More specifically, ethylene oxide (EO)-propylene oxide (PO) random copolymers are water soluble, and separate into polymer-rich liquid crystalline phases and a water phase depleted of polymer above a lower critical solution temperature (LCST) 14. Among them, thermo responsive polymers can be used in place of the commonly used PEG in dextran–PEG two-phase systems and, therefore, offer additional tunable properties 12. Many other ATPSs have been reported including ATPSs that utilize block co-polymers 10, 11, 12, 13. One of the most widely studied ATPS is the polyethylene glycol (PEG)/dextran system 9. The unique properties may be useful in applications such as theranostics, synthesis of complex structure particles, bioreaction/mineralization at the two-phase interface, and bioseparations.Īqueous two-phase systems (ATPSs) have been studied over the past decades due to its potential in bioseparation, high throughout assays, microfluidics, diagnostics, and bioreactors 1, 2, 3, 4, 5, 6, 7, 8. The ATPS based microparticle formation demonstrated in this study, serves as a novel platform for PLGA/polymer based tunable micro/nano particle and polymersome development. Further, due to the lower critical solution temperature (LCST) properties of Pluronic F127, the particles exhibit temperature responsiveness. The microparticles facilitate the simultaneous incorporation of both hydrophobic and hydrophilic molecules, due to their amphiphilic macromolecule composition. Depending on the PLGA concentration, the particles either formed a core-shell or a composite microparticle structure. The PLGA polymer, when emulsified in Pluronic F127/dextran ATPS, forms unique microparticle structures due to ATPS guided-self assembly. In overall, the results demonstrate the high potential of NADES to be used in cryobiology as alternative CPAs.Here, we produce poly(lactide-co-glycolide) (PLGA) based microparticles with varying morphologies, and temperature responsive properties utilizing a Pluronic F127/dextran aqueous two-phase system (ATPS) assisted self-assembly. Additionally, we have shown that NADES can act as CPA when cells are frozen at −20 ☌. Moreover, the results presented herein showed that NADES do not need to be removed from the freezing media after thawing the cells, which is a great advantage of these materials. For Hacat cell line a significant improvement on post-thawing recovery was observed. After freeze/thawing cycle, it was possible to observe that for L929 cells, NADES presented similar behaviour to Me 2SO.
To test NADES as CPAs, two cell lines were used, L929 and HacaT cells. Moreover, this cell line was highly tolerant to 10% (w/v) of NADES when compared to Me 2SO. All systems showed very little cytoxicity towards L929 cells at concentrations high as 1–2 M. Several combinations between natural primary metabolites that have been identified in animals that live in extreme cold climates were prepared. This work aimed at evaluating the potential of using natural deep eutectic systems (NADES) as cryoprotectant agents (CPAs).