Categorization of collagen type I and II blend hydrogel using multipolarization SHG imaging with ResNet regression

Sci Rep. 2023 Nov 9;13(1):19534. doi: 10.1038/s41598-023-46417-0.


Previously, the discrimination of collagen types I and II was successfully achieved using peptide pitch angle and anisotropic parameter methods. However, these methods require fitting polarization second harmonic generation (SHG) pixel-wise information into generic mathematical models, revealing inconsistencies in categorizing collagen type I and II blend hydrogels. In this study, a ResNet approach based on multipolarization SHG imaging is proposed for the categorization and regression of collagen type I and II blend hydrogels at 0%, 25%, 50%, 75%, and 100% type II, without the need for prior time-consuming model fitting. A ResNet model, pretrained on 18 progressive polarization SHG images at 10° intervals for each percentage, categorizes the five blended collagen hydrogels with a mean absolute error (MAE) of 0.021, while the model pretrained on nonpolarization images exhibited 0.083 MAE. Moreover, the pretrained models can also generally regress the blend hydrogels at 20%, 40%, 60%, and 80% type II. In conclusion, the multipolarization SHG image-based ResNet analysis demonstrates the potential for an automated approach using deep learning to extract valuable information from the collagen matrix.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Collagen
  • Collagen Type I*
  • Diagnostic Imaging
  • Hydrogels*
  • Image Processing, Computer-Assisted


  • Collagen Type I
  • Hydrogels
  • Collagen