Porous Polycaprolactone Microspheres Dispersed Hydrogel as Injectable Filler for Facial Volumization

The demand for injectable fillers in the medical aesthetics market has been growing significantly. However, current facial fillers such as Ellansé or Sculptra, which consist of solid microspheres, tend to sediment and aggregate during clinical use. Besides, their low porosity restricts the effective filling volume per injection. Herein, an injectable facial filler utilizing porous polycaprolactone (PCL) microspheres (PMs) was developed. A cost‐effective oil‐in‐water (O/W) emulsion solvent evaporation method was employed to prepare porous microspheres, incorporating camphene as the porogen. Scanning electron microscopy (SEM) analysis revealed that the pore distribution of the PMs was uniform. Owing to this unique PMs architecture, the specific surface area of the PMs was approximately 20 times greater than that of the solid control group. Furthermore, injectable fillers were prepared by incorporating solid or porous PCL microspheres into HA and CMC hydrogels, respectively. Compared to the HA hydrogel, the CMC hydrogel exhibited higher viscosity and suspension capacity for preventing PCL microsphere sedimentation. Additionally, the CMC/PMs filler delivered significantly enhanced mechanical properties relative to the CMC/SMs filler. Moreover, both the PMs and composite hydrogel fillers showed excellent cytocompatibility. Overall, the facile strategy proposed here represented substantial prospects for clinical translation in the field of facial volumization.