Quantitative Characterization of Collagen in the Fibrotic Capsule Surrounding Implanted Polymeric Microparticles through Second Harmonic Generation Imaging

PLoS One. 2015 Jun 30;10(6):e0130386. doi: 10.1371/journal.pone.0130386. eCollection 2015.

Abstract

The collagenous capsule formed around an implant will ultimately determine the nature of its in vivo fate. To provide a better understanding of how surface modifications can alter the collagen orientation and composition in the fibrotic capsule, we used second harmonic generation (SHG) microscopy to evaluate collagen organization and structure generated in mice subcutaneously injected with chemically functionalized polystyrene particles. SHG is sensitive to the orientation of a molecule, making it a powerful tool for measuring the alignment of collagen fibers. Additionally, SHG arises from the second order susceptibility of the interrogated molecule in response to the electric field. Variation in these tensor components distinguishes different molecular sources of SHG, providing collagen type specificity. Here, we demonstrated the ability of SHG to differentiate collagen type I and type III quantitatively and used this method to examine fibrous capsules of implanted polystyrene particles. Data presented in this work shows a wide range of collagen fiber orientations and collagen compositions in response to surface functionalized polystyrene particles. Dimethylamino functionalized particles were able to form a thin collagenous matrix resembling healthy skin. These findings have the potential to improve the fundamental understanding of how material properties influence collagen organization and composition quantitatively.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Biocompatible Materials / administration & dosage*
  • Collagen / chemistry*
  • Collagen Type I / chemistry
  • Collagen Type III / chemistry
  • Female
  • Fibrosis
  • Foreign-Body Reaction / metabolism*
  • Foreign-Body Reaction / pathology*
  • Materials Testing
  • Mice
  • Microscopy, Fluorescence, Multiphoton
  • Polystyrenes / administration & dosage*
  • Prostheses and Implants*

Substances

  • Biocompatible Materials
  • Collagen Type I
  • Collagen Type III
  • Polystyrenes
  • Collagen

Grants and funding

This work was supported by the National Science Foundation (www.nsf.gov) under grant CBET 1227867 and the Roy J. Carver Charitable Trust (https://www.carvertrust.org/) grant 13-4265. The authors also acknowledge support from NSF ARI-R2 (CMMI-0963224) for funding the renovation of the research laboratories used for these studies. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.