Probing Collagen Organization: Practical Guide for Second-Harmonic Generation (SHG) Imaging.

Second-harmonic generation (SHG) microscopy is a powerful microscopy technique for imaging collagen and other biological molecules using a label-free approach. SHG microscopy offers the advantages of a nonlinear imaging modality together with those ones of a coherent technique. These features make SHG microscopy the ideal tool for imaging collagen at high resolution and for characterizing its organization at various hierarchical levels. Considering that collagen organization plays a crucial role in fibrosis and in its development, it would be beneficial for the researcher working in the field of fibrosis to have a manual listing crucial points to be considered when imaging collagen using SHG microscopy. This chapter provides an answer to this demand with state-of-the-art protocols, methods, and laboratory tips related to SHG microscopy. We also discuss advantages and limitations of the use of SHG for studying fibrosis.