This article discusses the application of Raman spectroscopy combined with advanced statistical methods for characterizing complex (bio) chemical systems, which exhibit significant heterogeneity and variations from sample to sample.
As an example, the mechanism of YE8 polypeptide fibrillation, a complex dynamic system, was studied using 2-D correlation Raman spectroscopy. The evolution of secondary structure motifs with time was examined, and key stages of fibrillation, including the initiation process, were exposed. The application of multidimensional Raman spectroscopic signatures was proposed for the characterization and identification of complex (heterogeneous) nondynamic systems. The approach was successfully tested for forensic identification of body fluid stains. Blood, semen, saliva, sweat and vaginal fluid stains were extensively analyzed using NIR and Raman spectroscopy. The developed multidimensional signatures account for both the intrinsic heterogeneity of body fluid stains and variations between donors. (publisher abstract modified)