Nanoparticles (NPs) are continuously being developed for many applications including imaging, biomedicine, and everyday products. It is difficult to avoid contact with NPs such as titanium dioxide (TiO₂) NPs, which are widely used in sunscreens. However, the safety of TiO₂ NPs for skin contact and inhalation remains controversial. If NPs cannot penetrate the skin, they will be unable to circulate in the bloodstream, accumulate in the body, or cause side effects, ensuring their safety. Therefore, this study aimed to modify TiO₂ NP surfaces to inhibit their uptake in skin cells. Inspired by protein corona studies, bovine serum albumin (BSA) was chosen to functionalize TiO₂ NP surfaces via physical adsorption. The maximum BSA adsorption occurred at pH 5.0. The physicochemical properties (size, ζ-potential, morphology, ultraviolet (UV) absorption efficiency, and sun protection factor (SPF)) of TiO₂-BSA NPs were comparable to those of TiO₂ NPs, indicating that these properties did not affect cellular uptake. In the safety evaluation, TiO₂ NPs and TiO₂-BSA NPs exhibited high biocompatibility with skin cells and no phototoxicity after UVA and UVB irradiation. In the efficacy evaluation, both NPs possessed the same photoprotection abilities, reducing membrane damage and DNA breakage after UVA irradiation. Compared with TiO₂ NPs, TiO₂-BSA NPs showed substantially reduced skin penetration in Franz diffusion cells (91%) and human immortalized keratinocyte (HaCaT) cells (89%). A qualitative cellular uptake study using transmission electron microscopy and confocal laser scanning microscopy confirmed that TiO₂ NPs were more abundant than TiO₂-BSA NPs inside the HaCaT cells. These findings indicate that TiO₂ surface functionalization with BSA inhibits cellular uptake in skin cells while maintaining safety and UV protection efficacy, which might be extended to other NP-based sunscreens.

Polymeric particles have attracted vast attention for use in various fields, especially as drug carriers and cosmetics, due to their excellent ability to protect active ingredients from the environment until reaching a target site. However, these materials are commonly produced from conventional synthetic polymers, which impose adverse effects on the environment due to their non-degradable nature, leading to waste accumulation and pollution in the ecosystem. This work aims to utilize naturally occurring Lycopodium clavatum spores to encapsulate sacha inchi oil (SIO), which contains active compounds with antioxidant activity, by applying a facile passive loading/solvent diffusion-assisted method. Sequential chemical treatments by acetone, potassium hydroxide, and phosphoric acid were employed to remove native biomolecules from the spores before encapsulation effectively. These are mild and facile processes compared to other synthetic polymeric materials. Scanning electron microscopy and Fourier-transform infrared spectroscopy revealed the clean, intact, and ready-to-use microcapsule spores. After the treatments, the structural morphology of the treated spores remained significantly unchanged compared to the untreated counterparts. With an oil/spore ratio of 0.75:1.00 (SIO@spore-0.75), high encapsulation efficiency and capacity loading values of 51.2 and 29.3%, respectively, were obtained. Using antioxidant assay (DPPH), the IC₅₀ of SIO@spore-0.75 was 5.25 ± 3.04 mg/mL, similar to that of pure SIO (5.51 ± 0.31 mg/mL). Under pressure stimuli (1990 N/cm³, equivalent to a gentle press), a high amount of SIO was released (82%) from the microcapsules within 3 min. At an incubation time of 24 h, cytotoxicity tests showed a high cell viability of 88% at the highest concentration of the microcapsules (10 mg/mL), reflecting biocompatibility. The prepared microcapsules have a high potential for cosmetic applications, especially as functional scrub beads in facial washing products.

¹²⁷I-modified mIBG was successfully synthesized and grafted covalently to the surface of carboxylated PEG-GNPs. The particles were not toxic to the normal fibroblast cells while specifically internalized into neuroblastoma cells line via NET.

Salak peel extract has various biological properties befitting cosmeceutical applications; however, their practical uses are still limited due to their low water solubility and stability. Encapsulation technology was employed to alleviate these issues. In this work, we presented a simple method to prepare ethosome-encapsulated salak peel extract using green solvents (ethanol and water). For this purpose, we used 95% ethanol to extract salak peel and explored its activities. Results showed that, in addition to anti-oxidant, the extract also showed anti-tyrosinase, anti-inflammatory, and anti-bacterial (against S. aureus) activities. These activities indicate its potential uses in cosmeceutical applications. We further encapsulated the extract in ethosomes using a stirrer and green solvents for the preparation methods. The yielded ethosomes exhibited a size range of 120 to 205 nm, polydispersity index (PDI) of 0.15 to 0.25, and zeta potential of −35 to −60 mV depending on the amount of L-α-phosphatidylcholine used. The highest encapsulation efficiency was approximately 30%. The antiradical capacity and anti-inflammatory activities of salak peel extract were also found to be maintained after the encapsulation process. An in vitro biocompatibility study of the extract after encapsulation was also performed. The results not only indicated good biocompatibility, but also the potential skin-rejuvenating ability of salak peel ethosomes. A stability study was also performed, and the results suggested that these ethosomes were stable at different conditions. With further investigation, salak peel ethosomes, as presented here, can be suitable for cosmeceutical applications.