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High School Poster

HS Poster

Poster 24 - Application of Meta-Surface Thickness Measurement System to Collagen Tissue

Saturday, October 26, 2024
10:00 AM - 12:00 PM EST
Location: Exhibit Hall E, F & G

    Presenting Author(s)

  • Xuning Ye

    IEM OPALS intern
    UCSD Institute of Engineering in Medicine
    Upland, California, United States

    • Co-Author(s)

  • Zachary Z. Wang (he/him/his)

    Student Mentor
    University of California, San Diego: Institute of Engineering in Medicine, United States

  • SL

    Sophia Liu

    IEM OPALS Intern
    UCSD Institute of Engineering in Medicine, United States

    • Co-Author(s)

  • Rehaan Hassan

    IEM OPALS Intern
    UCSD Institute of Engineering in Medicine, United States

  • JH

    Jiayu Hu

    IEM OPALS Intern
    UCSD Institute of Engineering in Medicine, United States

    • Co-Author(s)

  • JZ

    Junxiao Zhou

    Postdoc
    University of California, San Diego, United States

  • ML

    Ming Lei

    Ph.D. Student Mentor
    University of California, San Diego: Institute of Engineering in Medicine, United States

  • Jianyu Ren

    Graduate Student
    University of California, San Diego, United States

  • CY

    Chun-Chieh Yu

    Postdoctoral researcher
    University of California, San Diego, United States

  • WX

    Wei Xiong

    Professor
    UCSD, United States

  • ZL

    Zhaowei Liu

    Professor
    Electrical and Computer Engineering, United States

    • Primary Investigator(s)

  • Linda Shi, PhD (she/her/hers)

    OPALS Program Director, Project Scientist, Co-director IEM
    University of California, San Diego: Institute of Engineering in Medicine
    La Jolla, California, United States


Introduction: Quantitative phase imaging (QPI) is a novel approach to collecting precise measurements of cellular structures, proving its potential as a powerful tool in biomedical research. Phase images are produced using a metasurface and the transport of intensity equation (TIE). This study explores the changes in collagen tissue thickness from laser ablation measured using a meta-device, demonstrating the adaptability of QPI for measuring thickness changes at the tissue level.

Materials and

Methods: The meta-device system consists of a geometric and propagation phase lens within the meta-device. The linearly polarized light is then separated by the meta-device into left and right circularly polarized components. A polarized camera (eBlackfly S USB3) then captures underfocused and overfocused images, generating phase images using TIE [1]. The system was configured with a laser emitting at 230 mW before the LUCPLFLN40X objective lens, with a ratio of 2.45 pixels per micron. Collagen tissue fibers were collected from lyophilized fibrous powder from type I bovine tendon, which are manually stretched to isolate fibers. Collagen tissue samples were subjected to precise laser ablation, using a Mai Tai femtosecond laser at a wavelength of 780nm [2]. Any measurements made on the collagen fibers were created using ImageJ. The ablation was carried out in a defined area, and the resulting changes in tissue thickness were captured using quantitative phase imaging. The system enabled the acquisition of underfocused and overfocused images, allowing us to solve the Transport of Intensity Equation (TIE) for accurate phase distribution and thickness measurement.

Results, Conclusions, and Discussions: Results and

Discussion: The results revealed a significant increase in the thickness of the collagen tissue surrounding the laser ablation site, with an observed 30% increase in thickness, from 7.78 to 10.68 um.

Conclusions: This novel application of the meta-device QPI technique to collagen tissue represents a significant expansion of the technology's utility in biomedical research. Although the system is able to measure the thickness of the collagen tissue, it was unable to take detailed thickness measurements, such as the thin line after the laser ablation which measured 1.12 µm in width. Future studies using this meta-device will focus on the improvement of resolution, so that images may be able to accurately measure to 1 µm or smaller. This study paves the way for future research in other biological tissues using the Eagle-Eye Inspired Meta-Device and highlights the system's versatility and effectiveness in measuring structural changes in different types of biological tissues.

Acknowledgements (Optional): This material was based upon work supported by a gift from Beckman Laser Institute Inc. to L.S., National Institutes of Health & National Institute of General Medical Sciences to W.X. and C.C.Y., and National Science Foundation - MRI project # 2320437 to Z.W. The high school students (*) participated in UCSD OPALS internship. Special thanks to Dr. Shu Chien for supporting the OPALS program.

References (Optional): [1] Junxiao Zhou, et al. Eagle-Eye Inspired Meta-Device for Phase Imaging, Adv. Mater., 2024, 36(32), 2402751.
[2] Michael W. Berns, et al. Chapter 5 Laser Scissors and Tweezers, Methods Cell Biol., 1997, 55, 71-98.