Self-assembly of platelet lysates proteins into microparticles by unnatural disulfide bonds for bottom-up tissue engineering

There is a demand to design microparticles holding surface topographies while presenting inherent bioactive cues for applications in the biomedical and biotechnological fields. Using the pool of proteins present in human-derived platelet lysates (PL), it is reported the production of protein-based microparticles via a simple and cost-effective method, exploring the prone redox behavior of cysteine (-SH) amino acid residues. The forced formation of new intermolecular disulfide bonds results in the precipitation of the proteins as spherical, pompon-like microparticles with adjustable sizes (15-50 μm in diameter) and surface topography consisting of grooves and ridges. These PL microparticles exhibit extraordinary cytocompatibility, allowing cell-guided micro-aggregates to form, while also working as injectable systems for cell support. Early studies also suggests that the surface topography provided by these PL microparticles can support osteogenic behavior. Consequently, these PL microparticles may find use to create live tissues via bottom-up procedures or injectable tissue-defect fillers, particularly for bone regeneration, with the prospect of working under xeno-free conditions.publishe