Event Title

Undergraduate Session IC: Natural Sciences Presentation 3 - Evaluation of the Photoprotective Ability of Sunscreens Using UV-Vis Spectrophotometry and Microbiological Model Systems (Poster)

Location

Hope Hall

Start Date

5-3-2022 9:00 AM

End Date

5-3-2022 10:15 AM

Session Chair

Jenissa Schleifenheimer

Mentor

Dr. Stefka Eddins and Prof. Susan Manahan

Description

Exposure to UV light damages skin’s DNA and may cause skin cancer. To protect skin from UV damage, sunscreens are commonly used. Their photoprotective ability is reported by a sun protection factor (SPF) rating. This project intended to determine the SPF values of some commercial sunscreens and evaluate the photoprotective ability of the sunscreens. Dilutions of each sunscreen were scanned with a UV-Vis spectrophotometer to find the absorption. The Mansur equation was used to calculate the SPF values of the sunscreens using the absorbances of the sunscreens. Baker’s yeast was used to evaluate the photoprotective abilities of two of the tested sunscreens. The chosen sunscreens were applied to the yeast and after UV exposure, the yeast colonies were counted. Advertised SPF ratings could not be confirmed spectrophotometrically, especially at the higher SPF and dilution levels. The microbiological experiment suggested that the sunscreens could successfully protect against UV ray damage since the growth in yeast colonies increased as the level of SPF used increased. It is proposed to investigated sunscreens’ matrix on the absorbance data by testing the Mansur equation against a mixture of sunscreens minus the inactive ingredients.

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Mar 5th, 9:00 AM Mar 5th, 10:15 AM

Undergraduate Session IC: Natural Sciences Presentation 3 - Evaluation of the Photoprotective Ability of Sunscreens Using UV-Vis Spectrophotometry and Microbiological Model Systems (Poster)

Hope Hall

Exposure to UV light damages skin’s DNA and may cause skin cancer. To protect skin from UV damage, sunscreens are commonly used. Their photoprotective ability is reported by a sun protection factor (SPF) rating. This project intended to determine the SPF values of some commercial sunscreens and evaluate the photoprotective ability of the sunscreens. Dilutions of each sunscreen were scanned with a UV-Vis spectrophotometer to find the absorption. The Mansur equation was used to calculate the SPF values of the sunscreens using the absorbances of the sunscreens. Baker’s yeast was used to evaluate the photoprotective abilities of two of the tested sunscreens. The chosen sunscreens were applied to the yeast and after UV exposure, the yeast colonies were counted. Advertised SPF ratings could not be confirmed spectrophotometrically, especially at the higher SPF and dilution levels. The microbiological experiment suggested that the sunscreens could successfully protect against UV ray damage since the growth in yeast colonies increased as the level of SPF used increased. It is proposed to investigated sunscreens’ matrix on the absorbance data by testing the Mansur equation against a mixture of sunscreens minus the inactive ingredients.