Vitamin E is a crucial liposoluble compound recognized for its significant antioxidant, anti-inflammatory, and skin-healing properties. It is widely used in cosmetics and dermatological applications, showing promise for treating conditions like atopic dermatitis, scars, acne, and promoting wound healing. Vitamin E’s antioxidant activity helps protect skin cells from UV rays and free radical damage, making it valuable for topical application.
Despite its benefits, the industrial use of vitamin E is significantly limited by its poor stability and low bioavailability, particularly under industrial processing conditions and when exposed to environmental factors like oxygen, light, and moisture. These challenges necessitate the development of innovative delivery systems capable of protecting vitamin E and enhancing its performance in formulations.
Microencapsulation is a strategy that protects vitamins by enhancing their stability and effectiveness. Among the various techniques available for microencapsulation, electrohydrodynamic (EHD) techniques have garnered attention due to their advantages. EHD techniques, which include electrospinning (producing fibers) and electrospraying (generating particles), use a high-voltage electrostatic field to create micro/nanostructures with beneficial properties like a high surface-to-volume ratio, porosity, and encapsulation efficiency. These techniques are considered an efficient alternative for producing microstructures containing vitamin E, creating a barrier that protects it from degradation and potentially improving its absorption and controlled release in biological systems.
Zein, a protein isolated from corn endosperm, was selected as an encapsulating agent for this research due to its favorable properties, including low moisture absorption, high thermal resistance, oxygen barrier capabilities, hydrophobicity, biodegradability, biocompatibility, and FDA recognition as safe. While zein has been used for hydrophilic molecules, its interaction and encapsulation efficiency with lipophilic compounds like vitamin E are less explored. This study aimed to address the limitations of vitamin E by encapsulating it in zein-based microstructures using EHD techniques, with potential applications in cosmetics and dermatology.
Methods
Zein solutions (1–30% w/v in 70% aqueous ethanol) and vitamin E solutions (1% w/w vitamin E relative to zein) were prepared. Conductivity and pH of the solutions were measured to understand their influence on microstructure formation.
Microstructures were produced using an electrospinning setup with a high-voltage power supply, controlled flow rate, and specific needle-to-collector distance. The morphology and size of the resulting particles and fibers, with and without vitamin E, were characterized using optical microscopy and scanning electron microscopy (SEM), with analysis performed using ImageJ software.
In vitro release studies were conducted in 70% ethanol using UV/Vis spectrometry to evaluate the release profile of vitamin E from the microstructures. Finally, the vitamin E microstructures were incorporated into preliminary cosmetic formulations, specifically aloe vera hydrogel and coconut oil, to assess their compatibility and potential application.
Key Findings
- Zein concentration significantly affects microstructure morphology.
- Low concentrations (1%, 5%, 15% w/v): micro/nanoparticles.
- High concentration (30% w/v): fibers.
- Intermediate concentrations (15–30% w/v): mixture of both.
- Average size of structures (1–15% w/v zein): 0.38–0.90 µm.
Diameter of 30% zein fibers: 0.49–0.74 µm. - Structures containing vitamin E were generally smaller/thinner than those without.
- Vitamin E did not significantly affect conductivity or pH of the 15% zein solutions.
- SEM images confirmed morphology observed by optical microscopy and showed no major differences between microstructures with and without vitamin E.
- Release studies in 70% ethanol showed:
- Faster release from low zein concentrations.
- Prolonged release from high concentrations (30% w/v).
- Vitamin E release was rapid in ethanol, likely due to its lipophilic nature and ethanol’s diffusion-promoting properties. Suggests these microstructures may not be suitable for ethanol-containing formulations.
- 30% zein fibers showed the most prolonged release profile in tested ethanol conditions.
- Microstructures were successfully incorporated into both aloe vera hydrogel and coconut oil.
- More uniform incorporation observed at lower zein concentrations (5%, 15% w/v).
Aggregation occurred at 30% due to fiber clumping. - Aloe vera hydrogel showed better structural compatibility with vitamin E microstructures.
Coconut oil demonstrated lower dispersion at higher concentrations, especially due to solidification at lower temperatures.
This study successfully demonstrated the encapsulation of vitamin E into zein-based micro/nanostructures using electrohydrodynamic techniques. A key finding was the strong influence of zein concentration on the morphology (particles vs. fibers) and its correlation with vitamin E release behavior.
While zein has been explored previously for encapsulation, this study specifically focused on its use with a lipophilic compound like vitamin E using EHD techniques. The successful incorporation of these microstructures into aloe vera hydrogel and coconut oil highlights their promising potential in cosmetic and dermatological formulations.
Future research should explore scale-up parameters, economic feasibility, and long-term stability. Studies simulating physiological conditions are essential to evaluate bioavailability and efficacy. The promising findings also open up possibilities for application beyond cosmetics—such as in food preservation or biomedical delivery systems. Co-encapsulation with other bioactive compounds could further enhance performance, although it introduces additional complexity.
Link to the study: https://www.mdpi.com/1420-3049/30/11/2306
