Recent advancements in sunscreen technology have led to the development of a novel lignin-based sunscreen that provides natural and high-performance UV protection. Researchers Yarong Li and Zhiguang Tang, introduces an innovative use of lignin, a polymer derived from the pulp industry, combined with titanium dioxide (TiO2) for enhanced sun protection factor (SPF) and aesthetic appeal. The study was published in the Journal of Bioresources and Bioproducts (1^✔ ✔Trusted Source
Development of Methylene Bis-Benzotriazolyl Tetramethylbutylphenol-grafted lignin sub-microspheres loaded with TiO2 for sunscreen applications

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What is Lignin?

Lignin is a complex organic polymer found in the cell walls of plants, particularly in wood. It is a byproduct of the pulp and paper industry and is known for its UV-absorbing properties and antioxidant capabilities.

Despite its beneficial properties, the application of lignin in commercial sunscreens has been limited due to:

• Low SPF Levels: Unmodified lignin exhibits inadequate sun protection.
• Dark Coloration: The inherent dark color of lignin makes it less appealing for cosmetic formulations.

Dual Modification of Lignin

To enhance the properties of lignin for sunscreen use, the researchers implemented a dual modification process:

• Chemical Modification: Methylene bis-benzotriazolyl tetramethylbutylphenol (MBBT) was grafted onto Alkali Lignin (AL), creating a new polymer known as AL-g-MBBT.
• Physical Transformation: The AL-g-MBBT polymer was then processed into sub-micron spheres, both with and without TiO2 loading.

TiO2 Loading

Titanium dioxide (TiO2) is commonly used in sunscreens for its excellent UV-blocking capabilities. By incorporating TiO2 into the lignin-based formulation, the researchers aimed to further enhance the SPF and improve the overall performance of the sunscreen.

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Implications of Enhanced SPF Performance and Color Improvement in Lignin-Based Sunscreens

Enhanced SPF Performance

The significant increase in sun protection factor from the modified formulations shows the effectiveness of the changes made to the lignin.

• The unmodified lignin provides minimal protection, which is not sufficient for sunscreen.
• The modified version offers a much higher level of protection, making it suitable for everyday use and effective against harmful UV rays.
• The version that includes titanium dioxide provides even greater protection, indicating it is suitable for more intense sun exposure situations, such as outdoor activities.

Improved Color Appeal

The improvements in color across the different formulations highlight an important aspect of cosmetic products: their visual appeal.

• The unmodified lignin has a dark color that can be unappealing to consumers.
• The modified lignin shows a better color, though there is still room for improvement.
• The version with titanium dioxide has a significantly lighter color, making it more attractive for cosmetic use.

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Photostability and Biocompatibility of Sunscreen

Photostability: The stability of the sunscreen formulations under UV irradiation was evaluated. The results showed that the sunscreens maintained their SPF and color performance even after three hours of UV exposure, indicating strong photostability.

Biocompatibility: Tests revealed that the modified lignin-containing sunscreen was non-toxic to human keratinocytes. This suggests that the new formulation is safe for application on the skin, a crucial factor for consumer acceptance.

The development of a lignin-based sunscreen represents a significant advancement in cosmetic science. By harnessing the natural properties of lignin and combining it with TiO2, researchers have created a high-performing, eco-friendly sunscreen that addresses common issues associated with traditional formulations.

This innovative approach not only enhances SPF and improves color but also ensures biocompatibility and photostability. The findings from this research could pave the way for a new generation of sustainable and effective sunscreen products, aligning with growing consumer demand for natural ingredients in skincare.

Reference:

1. Development of Methylene Bis-Benzotriazolyl Tetramethylbutylphenol-grafted lignin sub-microspheres loaded with TiO2 for sunscreen applications – (https://www.sciencedirect.com/science/article/pii/S2369969824000574)

Source-Medindia