UV-C generating robot to sanitize hospitals

May 11, 2008
This is interesting, the robot has a lamp that generates high intensity UV-C light pulses. These pulses disrupt the dna replication by causing severe dna damage in viruses, bacteria and fungi. I wonder how long it takes before an organism evolves to cope with the UV-C light. I wonder if organisms that have dna coding for melanin can produce enough melanin to cope with the uv-c. Black fungi that produce a lot of melanin are capable of withstanding and using ionizing radiation because of the melanin.
I also wonder if the plastic in the hospital do not degrade faster because of the light.




The Xenex robot, which looks like something straight out of a science fiction movie, produces UV rays that usually stay in the cosmos. It's changing the way hospitals handle infectious diseases by using UV light to sanitize the small organisms that cause us the biggest problems.
Hospital-Acquired Infections (HAIs)
Hospital-acquired infections or healthcare-associated infections (HAIs), are highly prevalent in the United States, with about 722,000 patients contracting one annually according to the Center for Disease Control and Prevention. This amounts to about one out of every 25 admitted patients. The fatality rate for HAIs is over 10%, making it one of the most serious problems modern hospitals face.

HAIs are transferred in various ways, depending on the type of infection. Many times, they are the result of bacteria that has developed a resistance to treatment with antibiotics.

The Xenex robot is an example of how medicine and engineering intersect to improve healthcare. This device is capable of using UV light to sanitize healthcare facilities with extraordinary thoroughness

Better Technology, Better Hospitals
Xenex began as a startup founded in 2008 by epidemiologists Dr. Mark Stibich and Dr. Julie Stachowiak. Their Xenex LightStrike Germ-Zapping Robot uses Full Spectrum Pulsed Xenon UV (PPX-UV) light to kill infection-carrying pathogens in hospital rooms.

Compared to the older technology of mercury UV disinfection, the Xenon bulbs used in the Xenex robot sweep across the entire UV-C spectrum, eliminating a wider range of infectious organisms, with the newest version of the robot targeting six of the most problematic pathogens for HAIs. It can also target the pathogens causing Ebola, Anthrax, HIV, and many other communicable diseases. The high-intensity light is sent in brief pulses out of the machine, which would be placed in the center of an empty hospital room for a total of only five minutes.

The light pulses aim to destroy the cells of the bacteria, viruses, and fungi that cause HAIs. Because UV-C rays from the sun are usually deflected by the ozone layer, earthly organisms have not developed a resistance to them. In methods similar to but more intense than antibiotic treatments, the population of pathogens is destroyed by irreversible destruction of their DNA so that they cannot replicate. The cell walls are also irreparably damaged, causing likely cell death.

In the Xenex robot, this is accomplished through four processes:

  • Photohydration – the UV light attracts water molecules into the DNA, which disrupts the replication process
  • Photosplitting – the “backbone” of the strands of DNA within the bacteria are broken
  • Photodimerization – the “rungs of the ladder” in a strand of DNA are fused together to give the improper code to any future replications. This is the only process that Mercury UV Disinfection is capable of.
  • Photocrosslinking – damages the cell wall by preventing the creation of new proteins.
These events effectively destroy the DNA replication and repair mechanisms within the cells. Different pathogens are susceptible to different wavelengths of UV-C light, which is why the broad spectrum provided by Xenon bulbs is so effective.