Research

Collagen is the primary load-bearing material in biological tissues, such as in heart valves and eyes. The organization of collagen fibers in soft tissues dictates their mechanical properties. Understanding the structure-function properties of collagenous tissues is essential to many biomedical problems. Polarized light imaging is an attractive method to study collagen structure, including fiber orientation, as the polarized light is sensitive to birefringent collagen fibers. Traditionally, thin tissue sections are required to achieve good visualization quality and high quantification accuracy. This method is destructive to tissue and slow, and is best suited for static sample imaging.

Being able to image bulk-tissue dynamics in real-time is desired to study their mechanical properties. This project aims to develop methods and instruments to meet that need. Structured light illumination has been proved to be an effective way to limit the imaging depth to the superficial tissue, thus eliminating the requirements of tissue-sectioning. Using advanced camera technologies, the imaging time can be further reduced, thus achieving real-time imaging capability. This imaging technique will be employed to study the biomechanics of ocular and heart tissues. This project is currently under investigation with collaborator Dr. Ian A. Sigal at the University of Pittsburgh.

Corneal cross-linking (CXL) is a clinical procedure used to treat the advanced keratoconus, an eye disorder characterized by progressive corneal thinning and impaired vision. CXL halts the progression of the condition and improves the vision by increasing the corneal stiffness. While CXL procedure produces favorable results, the current standard procedure takes 30 minutes. Efforts have been devoted to reducing the treatment time by increasing the optical power of the treatment. However, similar treatment results cannot be achieved.

This project aims to reduce the treatment while maintaining the treatment efficacy using a novel approach. This project is currently under investigation with collaborators Dr. Vishal Jhanji at UPMC and Dr. Jonathan Vande Geest at the University of Pittsburgh.

Spatial frequency domain imaging (SFDI) is a novel technique that quantifies optical properties (absorption and scattering) of soft tissues non-invasively. Two-dimensional sinusoidal patterns are typically utilized to probe the tissue. SFDI imaging has been used to study tissue hemodynamics, including blood concentration and oxygen saturation, which reveals important local blood circulation and perfusion pertinent to tissue health. SFDI imaging is typically performed in a static or quasi-static manner, which may miss important information between measurements. This project tackles this problem by introducing real-time imaging and quantification capability. This project will integrate advanced imaging system development, Monte-Carlo simulation, and in-vitro/in-vivo testing to ensure robust real-time performance.