23 巻 (2018) 1 号 p. 79-85
Imaging of latent fingerprints using light sources is favorable for subsequent short tandem repeat (STR) analysis because of its fewer risks of cross-contamination. Ultra violet (UV) light is well known to be effective for fingerprint visualization. However, the degradation of DNA by two kinds of UV lamps (254 nm and 306 nm) had been previously observed. In this study, we examined the effect of the light sources for the portable imaging system on STR analysis.
Twenty microliters of saliva donated from individuals #01 and #02 was dried on a glass slide, and irradiated by two kinds of halogen lamps (370-800 nm and 370-1100 nm) and by a continuous wave (CW) green laser (532 nm) for the hyperspectral imager, by a femtosecond pulsed near infrared laser (780 nm) for the two-photon excitation/ coherent anti-stokes Raman scattering (CARS) imager, and by a nanosecond pulsed near UV laser (355 nm) for the time-resolved spectroscopy. DNA was extracted from the irradiated saliva, quantified using a real-time PCR assay, and STR analysis was performed. The mean of the DNA concentration (n=4) was slightly reduced for the individual #01 by the near UV (355 nm) from 1.04±0.027 ng/μl to 0.795±0.054 ng/μl: however full STR profiles were obtained from all the samples irradiated by this UV. Light sources other than the near UV did not show significant reduction of DNA concentration under the examined conditions enough for fingerprint imaging, and full STR profiles were obtained.