Chemical sunscreens contain ingredients such as oxybenzone, which can cause skin allergies and other adverse health conditions. Some of these organic UV-filters are hormone disruptors and carcinogens. Under sunlight, the chemicals can degrade to produce cytotoxic and allergenic compounds. A popular substitute candidate would be physical filter such as titanium dioxide (TiO2). However, TiO2 generates undesirable reactive oxygen species (ROS) under sunlight. While sunscreen effect is achieved, the ROS produced can cause melanoma and photo-aging. Conventional vitamin C and derivatives are good radical scavengers but they become unstable when exposed to sunlight.
Ingredients serving as both antioxidants and UV filters would be highly attractive for personal care products. Lignin, nanodiamond and fullerene have shown light-stable antioxidant properties and broad-spectrum UV protection. Hence, recently, there has been increasing attention placed on the use of natural and nature-derived compounds in sunblock applications, due to their good UV-radiation protection property and antioxidant activity.
Lignin, nanodiamond and fullerene are safe, biocompatible and non-allergenic materials. In the unlikely event of skin penetration, these materials are non-cytotoxic as shown by cell studies. Lignin, the most abundant aromatic polymer from plants, is considered waste material in the pulp and paper industry. We harness the advantageous properties of lignin and convert it from waste to skincare products. The numerous UV chromophoric groups are responsible for its strong absorption capability in the UV-visible regions. Additionally, lignin can scavenge damaging reactive oxygen species (ROS). Therefore, incorporating lignin into sunscreens can enhance UV protection and further provide antioxidative property. Our results show that adding lignin into sunscreens improves the SPF value from 15 to 35+.
While nanodiamonds have gained much attention for biomedical applications such as drug delivery and imaging, skincare applications remain relatively unexplored. In the past decade, fullerene has become a popular and potent antioxidant ingredient for personal care products. Nanodiamond and fullerene provide broad-spectrum UV protection and their antioxidative property do not diminish after sunlight irradiation. These stable antioxidants would be superior to vitamin C and its derivatives.
The technology is mainly applied to personal care products such as serum, cream and lotion. The global UV filter market for personal care products looks very promising; it is expected to reach an estimated $672 million by 2021 with opportunities in organic and inorganic UV filter. The major drivers of growth are increasing awareness of consumers about UV-induced damage and the strong demand for anti-aging products. Emerging trends, which have a direct impact on the dynamics of the UV filter market, include green and natural UV filters and the introduction of nanoparticles in the manufacturing of UV filters.
The technology enables multiple benefits, such as sun-protection and antioxidation, in a single product. The ingredients are not only safe, biocompatible and non-allergenic materials, they also scavenge harmful ROS to prevent undesirable skin conditions and diseases.