This report describes the development of a double nanoemulsion system (water-in-oil-in-water, W/O/W) designed to incorporate volatile essential oils into a cosmetic repellent. The objective was to create a "cosmetorepelent" that combines mosquito protection with skincare benefits, such as moisturizing and anti-spot properties. The methodology involved the preparation of three distinct phases: an internal aqueous phase (W1) containing humectants and actives (panthenol, niacinamide, and hyaluronic acid), an oil phase (O) containing essential oils (lavender, grapefruit, and mint) and surfactants, and an external aqueous phase (W2) containing a solubilizer (PEG-40 Hydrogenated Castor Oil). High-energy emulsification techniques were employed to achieve a stable double nanoemulsion. Experimental results demonstrated that a gel formulation, stabilized by a specific surfactant blend (Span 80 and PEG-40) achieving an optimal HLB of 7, showed excellent stability and uniform micelle distribution under optical microscopy. In contrast, the liquid version presented challenges with creaming, indicating the need for further surfactant optimization. The study concludes that the double nanoemulsion approach is a viable strategy for creating a stable, multifunctional cosmetic repellent, with the gel formulation being the most promising candidate for further stability and repellency testing.

Quantum Dots (QDs) are nanostructures that have facilitated the development of various technologies due to their tunable optical and electronic properties. In this report, several methods for the synthesis and characterization of these QDs were investigated, along with different advancements and applications achieved in recent years. The objective was to functionalize them and develop light emitting diodes (LEDs) capable of producing ultraviolet (UV) light. In most cases, ZnO QDs were synthesized using the sol-gel method due to its production ease and accessibility. Likewise, they were functionalized using a series of thin films through the spin-coating process, along with a conductive material to enable electron transport across their surface. Absorbance and transmittance spectra (301380 nm) generated by zinc oxide (ZnO) QDs within the UV radiation wavelength were reported across several articles. This research led us to propose a future application for ZnO QDs: the development of a sanitizing machine using a self-developed LED. This proposal leverages the photoemissive and photocatalytic properties of these quantum dots while promoting an alternative to Cadmium-based QDs, which are environmental pollutants and toxic to humans.