Sticky Polyelectrolyte\nShield for Enhancing Biological\nHalf-Life of Growth Factors

Delivery of secretomes, which includes growth factors,\ncytokines,\nand mRNA, is critical in regenerative medicine for cell-to-cell communication.\nHowever, the harsh in vivo environment presents significant challenges\nfor secretome delivery. Proteolytic enzymes shorten secretomes’\nhalf-lives, and secretomes tend to rapidly diffuse at defect sites.\nTherefore, a delivery system that ensures prolonged retention and\nenhanced therapeutic efficacy of secretomes is required. In this study,\na Coating Optimized Drug Delivery Enhancement (COD<sub>2</sub>E) system,\na coacervate composed of dopamine functionalized fucoidan and poly-l-lysine, was fabricated for secretome delivery. The dopamine\nmodification significantly enhanced adhesive strength (>7-fold)\ncompared\nto that of the neat coacervates, which enabled rapid (5 min) and uniform\ncoating ability on collagen sponges. The COD<sub>2</sub>E system was\nable to encapsulate fibroblast growth factor (FGF2) and prolong the\nhalf-life of FGF2. Notably, its efficacy, demonstrated through a single\napplication of FGF2 encapsulated COD<sub>2</sub>E on collagen sponge,\nin a wound model demonstrated a successful tissue repair. The COD<sub>2</sub>E system is an effective growth factor delivery vehicle since\nit can protect growth factors, has an antioxidant ability, adheres\non various material surfaces, and is hemocompatible.