This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The overall goal of our research is to develop techniques for the investigation of intra- and intermolecular properties of collagen and to understand the properties of cartilage as a composite material. Characterization techniques using Atomic Force Microscopy (AFM) will be developed that will allow the determination of the nanomechanical properties of collagen molecules within type II/IX/XI collagen fibrils and determine the properties of the collagen/proteoglycan composite. Tissue engineering holds the promise of developing functional tissue substitutes, and providing mechanisms for the regulation and promotion of the repair and regeneration of a damaged tissue. Degenerative diseases of cartilage such as osteoarthritis (OA), and trauma from injury are responsible for joint pain in over 35 million people in the U.S. In the mature adult, cartilage has very little ability for self-repair. A notable amount of research has been carried out detailing the biochemical and biomechanical behavior of cartilage at the macroscopic level. However, information that provides a link between the biochemical characteristics and molecular constituents to the ultrastructural organization and material properties of cartilage is missing. . The specific Aims of the proposal are: Aim 1: The aim of our research is to develop atomic force microscopy (AFM) techniques to garner data that will promote a more thorough understanding of the composite structure of cartilage. Aim 2: To develop data analysis methods to analyze AFM data.