UV 101: A History of phototherapy, how it all began

Dr Niels Ryberg Finsen (1860-1904) was a Danish-Faroese Physician and Scientist. Diagnosed with Niemann-Pick disease, he was motivated to explore the scientific benefits of light. By 1893, his research led to the foundation of modern phototherapy. His laboratory work and clinical experiments successfully showed that rays of light such as red light and ultraviolet (UV) rays were effective in treating smallpox and lupus vulgaris respectively.

In 1903, Dr Niels Ryberg Finsen, founder of modern phototherapy, received the Nobel Prize in Physiology for the application of light in Medicine.



Back to the present, so how does Ultraviolet (UV) light kill germs?

Scientists and medical professionals have used UV light to kill germs and sanitize equipment for over a hundred years. The process is called Ultraviolet Germicidal Irradiation (UVGI).

On the electromagnetic spectrum, UV wavelengths are in between visible light and x-rays at the 100 nm to 400 nm range.

Absorbing light means absorbing energy - this is why objects get warm when exposed to the sun. When the DNA or RNA of a virus or bacterium absorbs energy from the UV radiation, it breaks down. This is known as a photolytic process. When the DNA or RNA is destroyed, the virus or bacterium is rendered inert and is no longer harmful.

The UV-C Wavelength (250-280 nm)

Although the UV spectral range varies from 100-400 nm, the UVC spectrum (which is a narrow range between 260-285 nm), is strongly absorbed by nucleic acids of microorganisms, causing viruses and bacteria to disintegrate at the cellular level. It is therefore considered to be the optimal germicidal range, with 262nm referred to as the peak germicidal wavelength. When UV-C photons penetrate viruses and bacteria, this damages the nucleic acid, making them unable to reproduce, rendering them microbiologically inactive.

Niels Ryberg sterilizers have a UV wavelength of 260-280 nm, so we got you covered!

References & Further Reading

University of California - Santa Barbara. "Ultraviolet LEDs prove effective in eliminating coronavirus from surfaces and, potentially, air and water." ScienceDaily. ScienceDaily, 14 April 2020. <www.sciencedaily.com/releases/2020/04/200414173251.htm>.

Casini B, Tuvo B, Cristina ML, et al. Evaluation of an Ultraviolet C (UVC) Light-Emitting Device for Disinfection of High Touch Surfaces in Hospital Critical Areas. Int J Environ Res Public Health. 2019;16(19):3572. Published 2019 Sep 24. doi:10.3390/ijerph16193572