![]() ![]() Incidences of cutaneous malignant melanoma, squamous cell carcinoma and basal cell carcinoma increase with ambient exposure to UV light 6. However, both UVB and UVA have been associated with increased risk of skin cancer 15. UVC and vacuum-UV are fully attenuated by Earth’s atmospheric gases 6, 12, 13 and studies have shown only limited evidence of UVC carcinogenicity in humans 14. UVA, UVB and UVC light all fall outside of the range considered ionising the lower limit being 10 eV 11. Both of these lesions distort the molecular structure: introducing bends and kinks and thereby impeding transcription and replication 8. UV irradiation can cause two types of DNA lesion: cyclobutane pyrimidine dimers 7 and 6–4 photoproducts 1. UV light has also been shown to be the most prominent carcinogen in our natural environment 1, 6. Studies examining the effect of ultraviolet (UV) light irradiation on DNA photodamage 1 have shown that damage to both mitochondrial and genomic DNA can lead to painful sunburn 2, photoageing 3, 4 and a degradation in skin barrier function 5. When coated on human skin, they are capable of slowing water evaporation and keeping the tissue hydrated for extended periods of time.ĭeoxyribonucleic Acid (DNA) is a long chain biopolymer that has been studied extensively in order to understand its relevance to human health. Additional characterisation of the films reveal they are highly absorbent and hygroscopic. Both hyperchromicity and increased light scattering could account for the increased film optical density after UV irradiation. To date the induction of a hyperchromic effect has been demonstrated using heat, pH, high salt mediums, and high energy ionising radiation. Subsequent and independent film irradiation with either UVA or UVB dosages upwards of 80 J/cm 2 both reduce UV transmittance, with reductions scaling monotonically with UV dosage. ![]() UV-Vis spectrophotometry reveals that DNA films with surface densities up to 0.031 mg/mm 2 can reduce the transmittance of incident UVC and UVB light by up to 90%, and UVA transmittance by up to 20%. The films are comprised of closely packed, multi-faceted and sub micron sized crystals. We report on ultraviolet (UV) light induced increases in the UV optical density of thin and optically transparent crystalline DNA films formed through self assembly. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |