Second harmonic generation microscopy for quantitative analysis of collagen fibrillar structure

Abstract

Second-harmonic generation (SHG) microscopy has emerged as a powerful modality for imaging fibrillar collagen in a diverse range of tissues. Because of its underlying physical origin, it is highly sensitive to the collagen fibril/fiber structure, and, importantly, to changes that occur in diseases such as cancer, fibrosis and connective tissue disorders. We discuss how SHG can be used to obtain more structural information on the assembly of collagen in tissues than is possible by other microscopy techniques. We first provide an overview of the state of the art and the physical background of SHG microscopy, and then describe the optical modifications that need to be made to a laser-scanning microscope to enable the measurements. Crucial aspects for biomedical applications are the capabilities and limitations of the different experimental configurations. We estimate that the setup and calibration of the SHG instrument from its component parts will require 2–4 weeks, depending on the level of the user’s experience.

Tailoring nanoparticle designs to target cancer based on tumor pathophysiology

“…2D) as tumors enlarged. There is a decrease of 9% per cm 3 in Picrosirius red intensity and the spectral shift in SHG peak intensity was characteristic of a loss in structural ECM via reduction in collagen fiber thickness and length (23)(24)(25).…”

Imaging the Nonlinear Susceptibility Tensor of Collagen by Nonlinear Optical Stokes Ellipsometry

“…Second harmonic generation (SHG) has a rich history in structural analysis of biological tissues (1)(2)(3)(4)(5), having been used to visualize structures including microtubule assemblies in brain tissue (6) and Caenorhabditis elegans embryos (7), collagen organization in tumors (8), pericardial tissue (9), human atrial myocardium (10), rat tails (11,12), corneas (13), and human skin (14), to cite just a select handful of representative studies. SHG has several properties that make it advantageous in biological imaging.…”

Techniques to assess bone ultrastructure organization: orientation and arrangement of mineralized collagen fibrils

“…It can experimentally be implemented using the same set-up as for multi-photon microscopy, with the addition of a detection filter at half the wavelength of the emission laser. Owing to the great popularity of the technique [191], more dedicated and sophisticated set-ups have been developed that take full advantage of the capabilities of SHG [111]. In recent years, there have been many studies on collagenous tissues using SHG microscopy, including cartilage [197], tendon [59], muscle [198], skin [199], fetal membranes [200] and vessels [201].…”