A free-standing multilayer film as a novel delivery carrier of platelet lysates for potential wound-dressing applications

Great efforts have been made to develop suitable bioactive constructs that release growth factors (GFs) in a controlled manner for tissue-regeneration applications. Platelet lysates (PLs) are an affordable source of multiple GFs and other proteins, and show great potential in the wound-healing process. Herein, poly-l-lysine (PLL) and hyaluronic acid (HA) were applied to build free-standing polyelectrolyte multilayer films (PEMs) using the PH-amplified layer-by-layer self-assembly method. Molecular simulations were performed, which showed that in the end layer of PEMs, HA was more attractive to PLs than was PLL. The HA/PLL films constructed with or without 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride (EDC) cross-linking both absorbed PLs successfully, exhibiting high hydrophilicity and GF absorptivity. The release profile of the EDC30 film lasted up to 2 weeks, and PL-loaded films supported cell proliferation, adhesion, migration, and angiogenesis in vitro. Moreover, due to sustained delivery of PLs, the membranes (especially the crosslinked film) helped to promote granulation-tissue formation, collagen deposition, and neovascularization in the region of the defect, resulting in rapid re-epithelialization and regeneration of skin. Mechanistically, the beneficial effects of a PL-loaded PEM coating might be related to activation of the hypoxia-inducible factor-1(Hif-1α)/vascular endothelial growth factor (VEGF) axis. As an off-the-shelf and cell-free treatment option, these biomimetic multilayers have great potential for use in the fabrication of devices that allow stable incorporation of PLs, thereby exerting synergistic effects for efficient wound healing.