This tenth episode of the 2019 R&D season of the NIJ-funded Just Science podcast series is an interview with Dr. Christopher Ehrhardt, professor at Virginia Commonwealth University, who explains a method for determining tissue type, age of evidence, and contributors in biological mixtures, using cellular autofluorescence signatures.
Background information for the interview notes that buccal, vaginal, epidermal, and blood cells each have unique intrinsic properties; however, when they are combined, it is difficult to identify which components are in the mixture. Dr. Ehrhardt has found a way to differentiate between cell types, estimate cellular age, and identify contributors to a mixture. In this interview, he discusses how autofluorescence data and cellular properties are being used to analyze samples without destroying the evidence. His research has focused on the cellular signatures of skin, saliva, blood, and vagina, with attention to changes in cell signatures as mixture samples age. The interview also covers efforts to quantify accuracy level in determining a cell signature.