Label-free polarization-sensitive multimodal optical microscopy for collagen characterization in tissue

This thesis presents the development and application of a novel multimodal polarization-sensitive optical microscopy system for comprehensive characterization of collagen in biological tissues, with a particular focus on tumor microenvironments. The work addresses the critical need for advanced imaging techniques to study collagen beyond morphological features, offering unprecedented insights into its structural, biophysical and biochemical properties across multiple scales. The thesis first introduces the important role of collagen in the extracellular matrix and tumor progression, and the concept of tumor-associated collagen signatures (TACS). Details on the methodology of the custom-built multimodal imaging system are then described, integrating polarization-sensitive second harmonic generation (PSHG), polarization-sensitive optical coherence microscopy (PSOCM), two-photon autofluorescence lifetime imaging microscopy (2PFLIM), and coherent anti-Stokes Raman scattering (CARS) microscopy. Key technical innovations include the design and calibration of a custom Fourier transform pulse shaper for low-photodamage CARS are highlighted. The system's capabilities are first demonstrated through the characterization of different collagen types (I-IV) in purified gels and complex tissue environments. Distinct optical signatures are identified for each collagen type, and the integration of PSOCM measurements into the PSHG numerical model significantly improves collagen helix angle estimations in thick tissues. A comprehensive analysis of collagen organization in rodent outer ears reveals depth-dependent distributions of different collagen types and enables identification of complex structures.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Electrical & Computer Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2024

Author dc:creator

• Yang, Lingxiao

Contributors dc:contributor

• Boppart, Stephen A
• Bhargava, Rohit
• Dragic, Peter D
• Zhao, Yang

• Optical Imaging
• Biomedical Optics
• Collagen

Statement dc:rights

• Copyright 2024 Lingxiao Yang

Language dc:language

eng, en

Handle dc:identifier

https://hdl.handle.net/2142/127390

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F127390