2.1. Preparation Protocol of Propolis Nanoparticle as Liquid Solution and Application
Merlin
Indian honey bee propolis was collected from Bhubaneswar, Odisha in November 2021. It then went through a cold-water washing process to remove the wax. The remaining part was dried, ground, and stored at 8 °C for further use. Propolis nanoparticle solution was prepared at room temperature by dissolving 0.22 g ground and dried propolis in 20 mL Milli-Q water, i.e., equivalent to 1.08 wt.%, using a 0.5-inch probe sonicator (Q500 SonicatorThe size distribution of the propolis nanoparticles was determined using dynamic light scattering (DLS) analysis (Zeta-sizer Ultra, Malvern Panalytical, Malvern, UK). This technique measures the intensity-based size distribution of particles in a suspension. The results revealed a mean particle size with a range of 88.6 to 103 nanometers in diameter, with the largest particle size of 140 nm in diameter. The zeta potential of the propolis nanoparticles was assessed using zeta potential analysis (Zeta-sizer Ultra, Malvern Panalytical, Malvern, UK). This technique measures the electrostatic charge present on the surface of the particles. The results demonstrated a zeta potential of −20.51 mV, indicating the stability of the nanoparticles.The morphology of the propolis nanoparticles was examined through field emission scanning electron microscopy (FE-SEM) (Merlin Compact, Carl Zeiss, Jena, Germany). Micrographs obtained from FE-SEM analysis showed flower-shaped nanoparticles with a relatively uniform size distribution with sizes ranging between 88.6 and 103 nm with a structural diameter of less than 100 nm (