Materials Science Challenges in Skin UV Protection: A Review

Abstract

UV radiation is one of the critical environmental stress factors for human skin, which can trigger various problems such as pruritus, burning, erythema, premature skin aging and skin cancer. Hence, UV protection has become an indispensable daily routine and the use of topical sunscreen products is rapidly increasing. However, there are emerging concerns over the efficiency and safety of existing chemical and physical UV filters used in consumer products. Furthermore, there is no universally approved method for assessing sun protection efficiency regardless of the immediate end user need to develop safer sunscreen products that afford broad‐spectrum photoprotection. It is evident that the current organic and inorganic UV filters have significant unfavorable impacts on human, environmental, and marine safety. Therefore, effective alternative UV filters should be established. This article comprehensively reviews the properties, safety, health and ecological concerns of various UV filters including TiO2 and ZnO nanoparticles as well as the limitations of the testing protocols and guidelines provided by major regulatory bodies. The photoreactivity of UV filters used in sunscreen remains a major challenge, and it is crucial to develop new sunscreen ingredients, which not only protect the consumer, but also the environment.

Nano-Structured Lignin as Green Antioxidant and UV Shielding Ingredient for Sunscreen Applications

“…The toxicity and pollution effects of actual commercial UV filters increased the interest for eco-friendly and natural alternatives [34]. Their use is considered an advantage not only for the ability to improve the SPF value in safer formulations, but also in improving the photostability of traditional UV filters [35].…”

Exploring Mycosporine-Like Amino Acids (MAAs) as Safe and Natural Protective Agents against UV-Induced Skin Damage

“…The most widely used physical sunblocks are TiO 2 and ZnO 2 , which protect against a broad spectrum of UV-B and UV-A radiation. The use of TiO 2 in sunscreens give it scattering power over a broad-spectrum [ 57 , 58 ].…”

Materials in advanced design of personal protective equipment: a review

“…The mechanism of radiation shielding in inorganic systems is the absorption of the electromagnetic wave for the transition of electrons from valence to conduction band. Due to the proximity between the bandgap and the UV energy, TiO 2 (3-3.2 eV) and ZnO (3.37 eV) are the most commonly used inorganic UV shielding materials so far [ 83 ] . Since the adhesion between inorganic oxides and textiles is usually poor, the oxides could be hybridized with organic matrix, such as PET, before coating on textile substrate for UV blockage [ 84 ] .…”

“…Compared with inorganic radiation-shielding materials, the organic ones could be directly made into fiber mats or combined with existing textile substrates with high affinity, rendering improved durability for the resulted anti-radiation PPEs. Organic UV shields usually contains aromatic structures with carbonyl groups which demonstrates conformational change upon UV absorption [ 83 ] . However, chemical reactions are usually accompanied with the conformational change, which could release detrimental chemicals and ROS, leading to the harm to the human skin.…”