Figure 6.

Different PGE2 biomaterial delivery systems. PGE2 delivery system is mainly divided into three categories including injectable hydrogels, liposomes or exosomes, and polymeric nanoparticles. Different hydrogel scaffolds containing PGE2 such as chitosan and pullulan hydrogel, contribute to the sustained release of PGE2. Exosomes and liposomes formed by the phospholipid bilayers encapsulate PGE2 within the hydrophilic core. Polymeric nanoparticles loading PGE2 are composed of natural or synthetic polymers such as poly (DAH/CBA) and PLGA. Platelet-inspired nanocell consists of an outer platelet-derived phospholipid bilayer binding PGE2 and inner PLGA nanoparticles encapsulated with cardiac stem/stromal cell secretory factors. PGE2 conjugation with siRNA to silence the apoptosis-related Fas genes is condensed with a reducible degradable cationic copolymer (poly (DAH/CBA)). Consistent with the platelet-derived nanocells, PGE2 molecules are exposed on the surface of the copolymer for targeting. The self-assembly of PLGA-b-PEG copolymer linked to an endothelial-targeted peptide forms poly PLGA-PEG-Peptide polymer encapsulating PGE2 in the core. PLGA, poly lactic-co-glycolic acid; poly (DAH/CBA), poly (1,6-diaminohexane, and cystamine bisacrylamide); PLGA-b-PEG, a poly (lactide-coglycolide acid)-b-poly (ethylene glycol) (PLGA-b-PEG) copolymer.