Microbial biosurfactant based nanoemulsions and their applications: A review

Abstract

Nanoemulsions exhibit a wide range of practical applications owing to their smaller particle size, stability, and enhanced bioavailability. Conventional surfactants widely used in nanoemulsion formulations namely, polysorbate 80, macrogolglycerol ricinoleate, and 4-octylphenol polyethoxylate have been associated with anaphylactoid responses, alterations in normal flora, cytotoxicity and tissue damage. The use of less toxic, environment-friendly microbial biosurfactants in the formulation of nanoemulsions have been demonstrated to manifest stability, slow drug release, enhanced skin permeability, and bioactivity. The type and composition of mixed microbial biosurfactants used in nanoemulsions can decrease the droplet size and synergistically increase the stability. Moreover, a lower concentration of drug-loaded surfactin-based nanoemulsion synergistically inhibited the proliferation of cancer cells by 50% (IC50). The scope of the current review is to focus on the prospect of substituting conventional surfactants with biosurfactants obtained from microbial origin for nanoemulsion formulations. It also aims to draw attention to the paucity of research in the combinatorial study of biosurfactants and functional drugs used in nanoemulsions. The review emphasizes the bioactivity of microbial biosurfactant-based nanoemulsions and their applications in diverse sectors. The differences in emulsion stability and size of microbial biosurfactant and conventional surfactant-based nanoemulsions have been highlighted. The study intends to promote comparative research between nanoemulsions prepared using conventional surfactants and microbial biosurfactants.