Spatially resolved macromolecular orientation in biological tissues using FT-IR imaging

Fourier-transform infrared spectroscopy (FT-IR) in combination with machine learning and chemometrics is an intensively developed, powerful tool for investigation of tissue biochemical composition with simultaneous microscopic visualization. This nondestructive, information rich and label-free technique has been successfully applied in cancer diagnostics. During the development of a disease or inflammatory processes, not only the chemical composition of tissues changes, but also their spatial organization. FT-IR imaging with linear polarization can provide new and useful information about chemically-specific orientation of macromolecules. Here, we present results of spatial macromolecular orientation in human, pancreatic tissue using four-polarization FT-IR method. Despite the much more complex chemical structure of tissue compared to artificial materials such as fibrillar polymers, the obtained orientations of biomolecules in tissue agreed with theoretical prediction.