Fully-biobased UV-absorbing nanoparticles from ethyl cellulose and zein for environmentally friendly photoprotection

Human-Hair-Derived Natural Particles as Multifunctional Sunscreen for Effective UV Protection

Excessive ultraviolet (UV) radiation can lead to a series of skin problems. Although commercial sunscreens can protect skin from UV-induced damage to an extent, the side effects caused by such products are still worrisome. Here, inspired by the natural photoprotection effect of human hair, we extracted the multifunctional particles from human hair as sunscreens for UV protection. Both in vitro and in vivo results indicate that hair-derived particles (HDPs) could effectively protect skin from UV radiation. Besides, HDPs retain the antioxidant capability of melanin in hair, which avoids UV-induced oxidative damage. In addition, the unique shape of HDPs can prevent them from penetrating into the skin, thus avoiding potential toxicity. Moreover, owing to their mesoporous structure, the particles can also be used as drug carriers. With the loading of octocrylene, the particles are more effective in blocking UV radiation. This study provides an ingenious tactic for the design and development of sunscreens from a natural substance.

Enhanced permeability and photoprotective potential of optimized p-coumaric acid-phospholipid complex loaded gel against UVA mediated oxidative stress

Photo-oxidative skin damage is mainly caused by the UV-A radiation of the sun. Synthetic sunscreens used to counter this acts mostly on the superficial skin layer and possess serious side effects. P-coumaric acid (PCA) is a UV-A protective plant phenolic having quick diffusion and distribution in superficial skin layers limiting its application as herbal sunscreen. The present study was designed to formulate an optimized phospholipid complex of PCA (PCAPC) through response surface methodology to enhance its skin permeation to deeper skin layers providing protection against photo-oxidative stress. PCAPC was characterized by FT-IR, DTA, PXRD, TEM, zeta potential etc. PCAPC was then incorporated into a gel formulation (PCAPC-GE) to facilitate its transdermal delivery. Physicochemical properties of the gel were assessed by pH, homogeneity, rheology, spreadability etc. In-vitro SPF and UVA-PF of the gel was evaluated and compared with conventional gel (PCA-GE). Ex-vivo skin permeation flux, permeability coefficient, skin deposition and dermatokinetic analysis were carried out to measure the rate and level of skin permeation. This was accompanied by in-vivo evaluation of PCAPC-GE and PCA-GE in the experimental rat model by measuring the various oxidative stress markers such as superoxide dismutase, catalase etc. PCAPC-GE provided high SPF and UVA-PF value compared to PCA-GE. The physicochemical parameters were suitable for transdermal application. PCAPC-GE enhanced the permeation rate of PCA by almost 6 fold compared to PCA-GE. Besides, a significant reduction of UV-A induced oxidative stress biomarkers were observed for PCAPC-GE. Thus, the PCAPC-GE may be an effective alternative of synthetic sunscreens due to its enhanced permeation and protection against UVA-induced oxidative stress.

Bio-Based Nanoparticles as a Carrier of β-Carotene: Production, Characterisation and In Vitro Gastrointestinal Digestion

β-carotene loaded bio-based nanoparticles (NPs) were produced by the solvent-displacement method using two polymers: zein and ethylcellulose. The production of NPs was optimised through an experimental design and characterised in terms of average size and polydispersity index. The processing conditions that allowed to obtain NPs (<100 nm) were used for β-carotene encapsulation. Then β-carotene loaded NPs were characterised in terms of zeta potential and encapsulation efficiency. Transmission electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction analysis were performed for further morphological and chemical characterisation. In the end, a static in vitro digestion following the INFOGEST protocol was performed and the bioaccessibility of β-carotene encapsulated in both NPs was determined. Results show that the best conditions for a size-controlled production with a narrow size distribution are lower polymer concentrations and higher antisolvent concentrations. The encapsulation of β-carotene in ethylcellulose NPs resulted in nanoparticles with a mean average size of 60 ± 9 nm and encapsulation efficiency of 74 ± 2%. β-carotene loaded zein-based NPs resulted in a mean size of 83 ± 8 nm and encapsulation efficiency of 93 ± 4%. Results obtained from the in vitro digestion showed that β-carotene bioaccessibility when encapsulated in zein NPs is 37 ± 1%, which is higher than the value of 8.3 ± 0.1% obtained for the ethylcellulose NPs.