Raman spectra of bloodstains could reveal age range of suspects or victims

Bloodstains at a crime scene can provide information about suspects or victims that can guide an investigation. Igor K. Lednev’s group at the University at Albany previously showed that Raman spectra of bloodstains can differentiate races and determine the sex of the individual—without DNA analysis. Now, Lednev and Kyle C. Doty show that Raman can also distinguish among blood from people in different age groups (ACS Cent. Sci. 2018, DOI: 10.1021/acscentsci.8b00198). Lednev and Doty collected spectra of bloodstains from three age groups—infants (younger than one year), adolescents (11–13 years old), and adults (43–68 years old). Hemoglobin dominates Raman spectra of blood when practitioners use an excitation wavelength of 785 nm. The intensity of peaks, particularly those at 375 cm⁻¹ and in the 1,210–1,270 cm⁻¹ region, differentiated the age groups, likely on the basis of small differences in protein secondary structure associated with age. Lednev plans to fill in gaps in the age model by analyzing bloodstains from additional age groups, with the goal of eventually building a model that will be able to determine chronological age rather than just an age group.