| Resumo: | The transition from the second to the third dimension is crucial to improve the reliability and predictive ability of cell-based assays, motivating the ongoing research on scaffold development to develop in vitro systems that could recapitulate the physiological cellular microenvironment. Proteins naturally occurring in the human body have been attracting attention as biomaterials for scaffold fabrication, due to their biochemical similarity with native tissues and potential allogenic source. In this context, METATISSUE has developed a novel photopolymerizable hydrogel based on human platelet lysates (PL) proteins. Despite the great performance in cell encapsulation tests, seeded cells do not adhere properly and the removal of human serum albumin (HSA) was proposed as a reliable approach to overcome this drawback. Herein, the goal of the presented work was the removal of HSA from PL using three phase partitioning (TPP) systems based on aqueous biphasic systems (ABS). These systems were investigated following two approaches, namely by the selective precipitation of HSA at the interphase or by the selective migration of the protein to one of the phases of ABS. A screening of eight ABS composed of different phase forming components was performed. The ABS composed of PEG 1000/citrate buffer presented the best performance, being 53% of the total HSA mass of PL retained at the top phase, while the remaining PL proteins precipitate at the interphase. These precipitated proteins can be easily isolated and used as an albumin-depleted PL (AD-PL) fraction for hydrogel fabrication. This system was then scaled-up (up to ca. 50 g) and the AD-PL obtained was modified with methacrylic anhydride (AD-PLMA), allowing the successful AD-PLMA hydrogel formation.
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