Preparation and release of novel frog egg-like microspheres by coaxial electrostatic spray technique

Novel frog egg-like microspheres, referred to as [email protected]2+/PCL-ME microspheres, were created by coaxial electrostatic spray technique, applying a gel formed by cross-linking sodium alginate (SA) with calcium ions as the shell material and a mixture of methyl eugenol (ME) and polycaprolactone (PCL) solution as the core material in the current study. Using optical microscopy, a uniform spherical shape was observed in the microspheres along with a distinct core–shell structure, while its porous internal and external features were visible in SEM images after drying. Furthermore, ME was released in microspheres for more than 12 weeks due to the dual sustained release method comprising a calcium alginate gel and PCL. During 8 weeks of trapping tests, ME-loaded microspheres were shown to be consistently effective.