ORIGINAL RESEARCH article
Front. Photonics
Sec. Biophotonics
This article is part of the Research TopicAdvances in Optical Methods for Biological Sample CharacterizationView all articles
Correlation between forward and backward generated SHG images of biological tissue relating to collagen structure and biomechanics
Provisionally accepted
- 1University College London, London, United Kingdom
- 2The University of Arizona, Tucson, United States
Select one of your emails
You have multiple emails registered with Frontiers:
Notify me on publication
Please enter your email address:
If you already have an account, please login
You don't have a Frontiers account ? You can register here
Second Harmonic Generation (SHG) microscopy has emerged as a powerful label-free tool for studying collagen microstructure in biological tissues, with increasing interest in the backward-detected signal due to its potential for translation to in-vivo imaging contexts. The origin of backward-SHG signal is not fully understood and, as such, interpretation of images remains challenging, as it represents complex optical interactions. This has led to misinterpretations of the collagen structure of biological tissues. Using a custom optical chamber allowing bidirectional SHG imaging of the cornea under controlled pressure, we assessed the spatial relationship between features in backward images and the underlying structural features of collagen in the paired forward images. Additionally, we demonstrate the potential of SHG imaging for investigating the biomechanical mechanisms relating to collagen and build-upon previous theoretical and experimental frameworks explaining forward and backward signal generation and current limitations in their interpretation.
Keywords: Backward SHG, Biomechanics, Collagen, Forward SHG, Microscopy, second harmonic generation
Received: 19 Dec 2025; Accepted: 26 Jan 2026.
Copyright: © 2026 Boutkhil, Moulding, Sawyer and Wilson. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Abby Wilson
Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.