A virtual classroom activity for teaching sunlight‐initiated DNA damage and its protection

Abstract

As a consequence of COVID-19 pandemic, most of classroom teaching went virtual in the academic year 2020-21. We took this opportunity to create a virtual activity for a biochemistry course for undergraduate nursing students at Milwaukee School of Engineering. It is well understood that prolonged exposure to sunlight is one of the major causes of skin cancer due to mutations in the keratinocyte DNA. Skin cancer is one of the most common forms of cancer in the US. UV-B radiation in the region of 290-320 nm is absorbed by skin cells resulting in mutated DNA which can lead to cancer. We developed the virtual activity with a dual purpose in mind. First, the activity would enhance their learning experience about DNA mutations using a 3D-printed model showing the biochemical DNA damage which could lead to skin cancer. Second, the activity could increase general awareness among students about the dangers of UVB-radiation exposure and protection strategies by directly testing everyday products such as sunscreens. We randomly picked nine commercially available sunscreens with various SPF values and tested their ability to protect from UVB radiation. Testing for protection from UVB radiation was performed using an in-house created customized chamber equipped with a UVB light source emitting a single wavelength at 310 nm. A thin, even layer of sunscreen was applied on a thin clear plastic wrap and exposed to UVB light. The sunscreens’ ability to block UVB radiation was quantitated compared to a control sample with no sunscreen.Further, using a 3D model of a DNA segment created by 3D printing at the Center for Biomolecular Modeling, we explained molecular-level changes. We created a two-part video. Part I narrates details of the sunscreen protection experiment. Part II explains the molecular details of DNA damage using 3D-printed model including (i) location of a broken A-T hydrogen bond (ii) location ofa T-T dimer and discussion of possible impact of the change in the DNA structure and (iii) explaining the formation of a ‘kink’ in the DNA strand as a result of the T-T photoproduct. The video will be accompanied by a student survey questionnaire on Canvas LMS. The goal of this study is to quantitatively test students’ understanding of this biochemistry topic before and after watching the virtual activity. Further, it is our hope that the activity will also increase general awareness among nursing students about the harmful effects of ultraviolet radiation exposure.