Nanoemulsion Formulation for Antimicrobial Applications

Nanoemulsions are kinetically stable dispersions of oil droplets in water (or vice versa) with typical droplet diameters below 200 nm. Their small size imparts optical transparency, high surface area and enhanced bioavailability of encapsulated antimicrobial agents. Formulation strategies commonly employ high‐pressure homogenisation, ultrasonication or microfluidisation in the presence of surfactants to lower interfacial tension and prevent coalescence. By entrapping essential oils, synthetic antimicrobials or metal nanoparticles within nanoscale droplets, these systems protect labile actives from degradation, improve their dispersibility in aqueous media and permit controlled release at target sites. Applications span food preservation, where nanoemulsions extend shelf life and reduce pathogen load on fresh produce; biomedical coatings, where sustained antimicrobial activity can inhibit device‐associated infections; and agricultural sprays, where enhanced adhesion and uptake improve efficacy against phytopathogens. Despite progress, challenges remain in ensuring long‐term physical stability, minimising surfactant toxicity and scaling production with reproducible droplet size distributions. Advances in green emulsifier design, interfacial engineering and in silico optimisation are poised to accelerate translation of nanoemulsion‐based antimicrobials into commercial and clinical settings.

Research from Nature Portfolio

Recent work has demonstrated a thymol‐based oil-in-water nanoemulsion stabilised by plant-derived saponin, prepared via sonication, which exhibits potent inhibition of a major soybean pathogen and concurrently promotes plant growth under glasshouse conditions. Another study explored high-pressure homogenisation to generate Origanum glandulosum essential oil nanoemulsions, revealing that processing parameters significantly alter volatile profiles, antioxidant capacity and anticancer potency of the encapsulated oil.

Nanoemulsion Formulation for Antimicrobial Applications publication trend

The graph below shows the total number of articles in nanoemulsion formulation for antimicrobial applications across all publications each year (not limited to Nature Index journals).

Technical terms

Nanoemulsion: A fine oil-in-water or water-in-oil dispersion with droplet diameters typically in the 20–200 nm range, stabilised by surfactants or emulsifiers.

Surfactant: Amphiphilic molecules that adsorb at oil–water interfaces, reduce interfacial tension and prevent droplet coalescence.

High-pressure homogenisation: A mechanical process in which a coarse emulsion is forced through a narrow gap at high pressure to generate nanoscale droplets.

Ultrasonication: The application of high-frequency sound waves to create cavitation bubbles that break down droplets and disperse phases at the nanoscale.

Zeta potential: An electrokinetic parameter reflecting the surface charge of droplets; higher absolute values typically indicate greater colloidal stability.

References

1. An Overview of Micro- and Nanoemulsions as Vehicles for Essential Oils: Formulation, Preparation and Stability. Nanomaterials (2020).
2. Thymol nanoemulsion exhibits potential antibacterial activity against bacterial pustule disease and growth promotory effect on soybean. Scientific Reports (2018).
3. Effect of nanoencapsulation on volatile constituents, and antioxidant and anticancer activities of Algerian Origanum glandulosum Desf. essential oil. Scientific Reports (2020).
4. Inactivation of Salmonella using ultrasound in combination with Litsea cubeba essential oil nanoemulsion and its bactericidal application on cherry tomatoes. Ultrasonics Sonochemistry (2023).
5. Garlic essential oil in water nanoemulsion prepared by high-power ultrasound: Properties, stability and its antibacterial mechanism against MRSA isolated from pork. Ultrasonics Sonochemistry (2022).
6. Effects of clove essential oil (Caryophyllus aromaticus L.) nanoemulsion incorporated edible coating on shelf-life of fresh cut apple pieces. Journal of Agriculture and Food Research (2023).