title: Effect of ultraviolet C radiation on biological samples.
abstract: OBJECTIVE
  To examine the influence of ultraviolet C (UVC) radiation on blood, saliva, semen, and naked DNA samples for preventing DNA cross-contamination on working surfaces in laboratories.
  
  
  METHODS
  Blood, saliva, semen, and DNA isolated from buccal swab samples were obtained from a single male donor and applied to the laboratory working surfaces. UVC radiation was applied to these diluted and undiluted samples with or without previous decontamination of the working surfaces with 10% sodium hypochlorite and 20% ethanol. Genomic DNA was extracted using Chelex. After quantification, DNA was amplified using the AmpFlSTR® NGM™ PCR Amplification Kit. We tested and statistically analyzed DNA concentration, UVC dose, sample volume, radiation time, the number of correctly detected alleles on genetic loci, and the number of correctly detected alleles in four groups in which 16 loci were divided.
  
  
  RESULTS
  When working surfaces were not decontaminated and were treated only with UVC radiation in the laboratory, the genetic profile for naked DNA could not be obtained after 2 minutes of UVC radiation and for saliva after 54 hours. For blood and semen, a partial genetic profile was obtained even after 250 hours of UVC radiation in the laminar. When working surfaces were decontaminated with 10% sodium hypochlorite and 20% ethanol, genetic profile could not be obtained for naked DNA after 2 minutes, for saliva after 4 hours, for blood after 16 hours, and for semen after 8 hours of UVC radiation in the laboratory.
  
  
  CONCLUSIONS
  It is recommended to carefully and thoroughly clean working surfaces with 10% sodium hypochlorite and 20% ethanol followed by minimal 16-hour UVC exposure (dose approximately 4380 mJ/cm2) for complete and successful decontamination.
authors.affiliation: Forensic Science Centre "Ivan Vucetic", General Police Directorate, Ministry of Interior, Ilica 335, 10000 Zagreb, Croatia. gmrsic@mup.hr
authors.forename: Branka
authors.initials: B
authors.lastname: Gršković
authors.forename: Dario
authors.initials: D
authors.lastname: Zrnec
authors.forename: Maja
authors.initials: M
authors.lastname: Popović
authors.forename: Maja Jelena
authors.initials: MJ
authors.lastname: Petek
authors.forename: Dragan
authors.initials: D
authors.lastname: Primorac
authors.forename: Gordan
authors.initials: G
authors.lastname: Mršić
mesh_terms: D001769:Blood / Q000528:radiation effects*; D004247:DNA / Q000528:radiation effects*; D004249:DNA Damage; D005784:Gene Amplification; D006801:Humans; D008297:Male; D016133:Polymerase Chain Reaction; D011829:Radiation Dosage; D012463:Saliva / Q000528:radiation effects*; D012661:Semen / Q000528:radiation effects*; D014466:Ultraviolet Rays; D055815:Young Adult
chemical_list: D004247:DNA