A Biobased Biodegradable Sunscreen that is Safe, Removes Environmental Impact, is Inclusive of all Skin Tones, and is for the Purpose of Eliminating Disparities in Melanoma Mortality Rates

Over 9000 people die of Melanoma in the United States every year [1]. It is the most common skin cancer. However, not all are affected equally. While white patients have a higher incidence rate, patients of color have a significantly higher fatality rate once melanoma develops [2]. Even the darkest skin tones with the greatest amount of melanin are not protected from ultraviolet (UV) radiation. DNA damage from UV light can be measured in all skin types and all skin types may develop melanoma from DNA damage [3]. While chemical sunscreens have made progress toward removing aesthetic concerns, these chemicals can enter the bloodstream with uncertain health effects. Physical sunscreens based on ZnO/TiO2 do not have the same risk, however the white/”ashy” appearance on darker skin limits their adoption. This proposal is for the development of a physical sunscreen based on the non-toxic, biocompatible, and naturally occurring polyester poly-3-hydroxybutyrate (PHB) that is by nature less whitening than physical sunscreens on the market, allowing for greater adoption by individuals with darker skin. PHB is part of the natural carbon cycle and readily biodegrades in marine environments. Light transmission through PHB’s crystal structure increases with increasing wavelength; PHB blocks up to much more UV light than visible light, giving it a less white appearance than minerals that reflect visible light. The specific aims of this proposal are to: 1) Produce and isolate PHB for sunscreen formulation; 2) Obtain a range of particle and crystal spherulite sizes by varying spray drying/annealing parameters; and 3) to study the effects of particle size and spherulite size on UV light transmission and sensory acceptance (specifically grittiness). It is important to design sunscreen products that address the tone issues while limiting uncertain health/environmental risks. Making sunscreen that is inclusive of all skin tones will help increase application to all ethnicities equally and will help lessen the health gap by reducing the mortality rate of people of color who develop melanoma. Our innovation will address these issues and is superior to other sunscreens. Our innovative sunscreen is designed to be (1) bio-based and biodegradable making it (2) a safe and healthy option, (3) that doesn’t have a perceivable tone on any skin color, and (4) has removes the negative environmental impact that is associated with many sunscreens on the market today. PUBLIC HEALTH RELEVANCE: Due to bias in the sunscreen industry, there is unequal application of sunscreen in light and dark-skinned communities and ultimately this has helped result in a much higher mortality rate for dark-skinned individuals who develop melanoma. As an additional deterrent, most sunscreen products are made of physical blockers that make darker skins appear ashy, and sunscreens that don’t are typically chemical based where there is considerable concern around the safety of these chemicals both for human health and the health of natural environments. We are developing a physical sunscreen based on the naturally occurring, non-toxic, biodegradable microbial polyester poly-beta-hydroxybutyrate that is far less whitening than physical sunscreens on the market today.