Synthesis of Polymeric Nanoparticles Using Fungal Biosurfactant as Stabilizer

Polymeric nanoparticles (PNPs) are highly valuable across various industries due to their advantageous properties, including biocompatibility and enhanced release control, which are particularly important for pharmaceutical and cosmetic applications. Fungi, through secondary metabolism, are capable of producing biosurfactants (BSs)—amphiphilic molecules that reduce surface tension and can therefore substitute synthetic surfactants in PNP stabilization. In this study, we investigated the production of biosurfactants by the endophytic fungus Aspergillus welwitschiae CG2-16, isolated from the Amazon region, as well as its use as a PNP stabilizer. The fungus exhibited a 36% reduction in the surface tension of the culture medium during growth, indicative of BS production. The partially purified biosurfactant demonstrated an emulsification of 24%, a critical micelle concentration (CMC) of 280 mg/L, and an FTIR spectrum suggesting a lipopeptide composition. The biosurfactant was employed in the synthesis of poly-ε-caprolactone (PCL) nanoparticles via nanoprecipitation and emulsion/diffusion methods. Nanoprecipitation yielded spherical nanoparticles with a low polydispersity index (0.14 ± 0.04) and a high zeta potential (−29.10 ± 8.70 mV), indicating suspension stability. These findings highlight the significant role of biosurfactants in polymeric nanoparticle formation and stabilization, emphasizing their potential for diverse applications in pharmaceutical, cosmetic, and other industrial sectors.