Nanoemulsions Based on Sunflower and Rosehip Oils: The Impact of Natural and Synthetic Stabilizers on Skin Penetration and an Ex Vivo Wound Healing Model

Abstract

Vegetable oils offer excellent biological properties, but their high lipophilicity limits their bioavailability. This work aimed to develop nanoemulsions based on sunflower and rosehip oils and to evaluate their wound-healing activity. The influence of phospholipids of plant origin on nanoemulsions’ characteristics was investigated. A nanoemulsion prepared with a mixture of phospholipids and synthetic emulsifiers (Nano-1) was compared with another prepared only with phospholipids (Nano-2). The healing activity was evaluated in wounds induced in human organotypic skin explant culture (hOSEC) based on histological and immunohistochemical analysis. The hOSEC wound model was validated, showing that high nanoparticle concentration in the wound bed interferes with cell mobility and the ability to respond to the treatment. Nanoemulsions were 130 to 370 nm, with a concentration of 1013 particles/mL, and a low potential to induce inflammatory processes. Nano-2 was three times larger than Nano-1 but less cytotoxic and could target the oils to the epidermis. Nano-1 permeated intact skin to the dermis and showed a more prominent healing effect than Nano-2 in the hOSEC wound model. Changes in the lipid nanoemulsion stabilizers impacted the cutaneous and cellular penetration of the oils, cytotoxicity, and healing kinetics, resulting in versatile delivery systems.

Unveiling the mechanisms for the development of rosehip-based dermatological products: an updated review

“…Faster cellular uptake of Nano−1 for fibroblasts (up to 80%) has been observed compared with Nano-1 after 5 min of incubation. The uptake percentage of both Nano-1 and Nano-2 presented similarities after 15 min of incubation, which may be due to their different composition of synthetic emulsifiers and not due to their nanoparticle size ( Pereira Oliveira et al, 2023 ). Nano-1 and Nano-2 have also been assessed for their wound healing rate in ulcers.…”

“…Despite their same concentrations in sunflower and ROs, it has been revealed that Nano−1 present a rapid healing rate compared with Nano−2, suggesting an increased permeability and delivery to the epidermis layer. Therefore, both nanoemulsions may be used in the treatment of wounds, (particularly Nano−1), but also as a treatment in other dermatological disorders, such as psoriasis and atopic dermatitis ( Pereira Oliveira et al, 2023 ). Previous studies have also confirmed the use of AA from rosehips to successfully develop microemulsions and liquid crystalline systems incorporated with AA, creating a nano-cosmetic that can be used in the aesthetic treatment of stretch marks ( Pichonelli et al, 2016 ).…”