Development of Near Infrared Spectral Analysis for Native, Engineered and Degraded Cartilage

Abstract

Articular cartilage helps in the motion of the diarthroidal joints by providing a near frictionless load bearing surface. Identification of changes in articular cartilage chemical and structural properties that arise from degeneration and suboptimal tissue repair have been the target of many studies. Current methods that evaluate these changes frequently involve destructive specimen preparation. Thus there is a need to develop a method to accurately evaluate changes in cartilage during disease or repair processes. Fourier transform infrared (FTIR) spectroscopy in the mid-infrared (MIR) spectral range is based on molecular vibrations and has been used to study the chemical and structural properties of biological tissues, including cartilage. However, this technique generally requires extensive sample preparation and modification of the intact tissue. An alternative approach is to use near-infrared spectroscopy (NIRS) which does not require sample preparation due to higher depth of penetration. This doctoral dissertation focuses on identification of NIR spectral features to evaluate the major components of cartilage. These NIR spectral features are then used to evaluate compositional changes in engineered and degraded cartilage, and the results validated with histological, biochemical, mechanical and MIR analysis of the same tissue. Together, these studies lay the groundwork for clinical and in situ applications of NIRS.