As summer approaches, many turn to sunscreen to help protect their skin. As technology advances, many scientists question if sunscreen not only protects skin, but also DNA. Deoxyribose nucleic acid (DNA) is an essential part of any living organism because it contains biological instructions, making each individual species different. It is passed from organism to offspring during reproduction.
Ultraviolet (UV) rays are dangerous. They can not only inflict damage to the skin, but they can also penetrate the DNA. The deadly rays from the sun can cause damage to the DNA in the form of DNA strand breaks. The DNA is cut into one or two strands. Having a double- stranded break is critical and is possibly mutagenic. Strand breaks are detrimental because they affect the expression of multiple genes and cell signaling pathways.
The ultraviolet photons, which are shorter in wavelength and higher in energy, strikes the skin and generates free radicals that directly damages DNA. DNA absorbs both the UVA and UVB rays which, left unrepaired, can lead to two types of cancers: non-melanoma or melanoma. Also, over a short period of time, it can lead to premature aging of the skin, suppression of the immune system, and a sunburn (Hansen, 2017).
Luckily, sunscreen was invented. Sunscreen is a product that combines several ingredients that help prevent the sun’s harmful radiation from reaching the skin and it comes in a variety of forms: sprays, lotions, and gels/waxes. To get the most protection from sunscreen, look for ones with the highest SPF (Sun Protection Factor). SPF is the measure of the ability of the sunscreen to protect against UVB rays (one’s that burn the skin) which can consequently protect against damaging skin.
Specific FDA-approved chemicals are permitted to be used in sunscreen and are proving to be successful. Some of which are zinc oxide, titanium oxide, avobenzone, and oxybenzone. The inorganic chemicals in sunscreen reflects UV rays while the organic compounds absorb the radiation. As the compounds absorb the radiation, the sunscreen slowly break down and release heat (USEPA, 2017).
Scientists are fascinated by the wonders of the sun. They continue to work to improve sunscreen, but as the ozone layer slowly depletes, more and more UV rays enter into the atmosphere. This makes it harder to create a sunscreen that lasts for a long time. They fight issues such as water rubbing off the sunscreen or sunscreen not lasting long enough. Many amazing technological advances have been made to prevent UV radiation, however there is no sunscreen that protects 100% of the rays that enter into the atmosphere. Scientists recommend reapplying sunscreen every two hours and to use one with an SPF higher than 30. With all of the work put into sunscreens and research, we are bound to one day create a perfect solution.
As aforementioned, the research question is, “Does Sunscreen Protect DNA?” I plan on answering the question by doing research on previous experiments done in the past. Because UV radiation/sunscreen is a still a “hot topic,” I believe that I will find an abundant amount of information pertaining to the answer to my scientific question. There have been numerous experiments studying the effect of sunscreen on the skin and the DNA. Some include, a setting where scientists have assessed the ability of two sunscreens to inhibit DNA photodamage in the skin in situ, using X-rays, and by studying how effectively sunscreens protect yeast cells from UV radiation.
All of the aforementioned experiments provide an answer to the question which therefore makes it logical. Antony R. Young assessed the ability of sunscreen to inhibit DNA photodamage in the skin in situ studied to see if specific ingredients had sun protection factors when assessed with solar simulating radiation in volunteers with skin type I/II. According to the Fitzpatrick Skin-Type Chart, type I is having a highly sensitive, always burns, and never tans. Type II is very sun sensitive, burns easily, and tans minimally. In the experimental design of DNA photoprotection studies, they tested to see if SPF indicated the amount of protection against any DNA photodamage. Photodamage is caused by photolesions. Photolesions are lesions (a region in a tissue that has suffered damage by a disease or injury) formed by exposure to light. By collecting the statistical analysis, scientists use this experiment
to study how or if DNA photolesions are affected by UV radiation (Young, 2000). This can also answer the question, “Does skin protection factors would indicate the level of protection against DNA photodamage?”
The next experiment studies the “molecular sunscreen.” More specifically, it looks at how DNA protects itself from UV light. In this scientific study, scientists use X-rays to measure the ultrafast response of the nucleobases of the DNA to the light. They found that the UV excited state in thymine (a nucleobase in DNA) decays rapidly which dissipates the destructive UV energy. When the scientists made this research, it gave them an inside look on how DNA protects itself from light-induced damage. Learning the results from this experiment can simply provide an answer to my question proving that sunscreen does not protect DNA, but that DNA has evolved to protect itself against the harmful radiation (Department of Energy, Office of Science, 2015).
Many high schoolers study how different sunscreens protect yeast cells from damage caused by UV radiation. They do so by comparing different SPFs of the same brand or different brands with the same SPF. The main questions asked in this experiment are, “Does the SPF of sunscreen make a difference,” “Do some brands provide better protection than others,” and many more. The researchers use ordinary baker’s yeast (Saccharomyces cerevisiae) to study the effects of UV radiation. We use this specific type of yeast because they have genes for DNA repair which are extremely similar to the corresponding human genes. The use of yeast cells serves as a model system to learn about the effect of the harmful radiation on cells. This experiment shows
that UV-induced mutations lead to cell death and it proves that sunscreen is needed to protect DNA.
General Methods/Proposed Results
The first experiment mentioned in this paper was performed by Antony R. Young. He, along with other scientists, studied the protection of Ultraviolet A and B sunscreens against in situ Dipyrimidine photolesions in human epidermis to see if it was able to protect from a sunburn. Using two different sunscreens with different spectral profiles, scientists would use solar simulating radiation on volunteers with different skin types. They exposed the sunscreen-treated sites to the solar simulating radiation and to their control sites. Using thymine dimers and image analysis, they can observe the damage in the DNA. After analyzing the images, scientists have discovered that the DNA protection factor is similar to the sun protection factor. For the sites that were not treated with sunscreen, the photodamage that occurred on the DNA may lead to future skin cancer. An alternate result to this experiment is finding out that there is no difference in the level of sun protection factor. If this were found to be true, scientists would be able to focus on creating one specific formula to protect from the sun’s dangerous rays.
The next experiment is studying how DNA protects itself from UV light. The biotechnology that scientists used for his experiment were X-rays. They measured the response of DNA’s nucleobases to ultraviolet light. The nucleobases encode genetic information inside the DNA. More specifically, scientists studied the motion of electrons and nuclei of a light-expose
molecule using spectroscopic approaches. The one nucleobase that they observed was Thymine. They have discovered that the UV energy collected by the DNA dissipates rather than having it be detrimental. This experiment would answer the simple question, “Does sunscreen protect DNA?” Because scientists discovered that the DNA can protect itself from harmful radiation, it appears to be that DNA would be alright without any sunscreen. However, an alternate result would be that DNA only dissipates the heat to spread to other cells. This could lead to other types of ailments within the body. Sunscreen would be needed to act as a wall for the DNA. If sunscreen was used to protect the DNA, the DNA would not have to protect itself.
The final experiment conducted can easily be recreated by many high school students. This experiment studies how much damage UV radiation causes on yeast cells. Similar to the first experiment, researches would compare different SPFs of the same sunscreen brand or of differing brands. After analyzing the results, scientists have discovered that UV radiation does not automatically kill yeast cells, but that the DNA is damaged. They have also discovered that mutations occur. Mutations are alternations to a DNA sequence (Vidyasagar, 2016). Mutations directly affect an organism’s characteristics since their genes are being changed. Some of the mutations may be beneficial or fatal. This experiment would answer the question, “what happens if DNA gets damaged by ultraviolet radiation?” This experiment could also answer the question, “what would happen after a cell has been exposed to radiation?” Scientists have discovered that if a DNA molecule has been damaged and has not been repaired before the DNA
replicates, then the cell would most likely die (Johnson, 2001). An alternate result to this experiment is applying sunscreen to yeast cells. If scientists were to apply sunscreen to the yeast cells, they would be able to test to see if sunscreen protects the DNA within the cells therefore preventing all of the side effects from occurring.
The paper reviews current studies on the effect of ultraviolet radiation on DNA. With the extensive research conducted, DNA damage from the sun is apparent. If not protected or treated, the damage can lead to further abnormalities such as skin cancer. As the warmer weather approaches, it is crucial to wear sunscreen with a decent amount of sun protection factor.
This paper looks at experiments done by numerous scientists. Using biotechnology, scientists were able to conduct many experiments from studying the molecular protection, studying the effect of UV radiation on yeast cells, and studying radiation in situ. Scientists have discovered that UV radiation has a huge toll on DNA and sunscreen can be used to protect it.