ABSTRACT
This chapter discusses the recent advances in the optical clearing (OC) of cartilage in the visible and near-infrared (NIR) spectral range. The reduction of natural opacity and improved optical probing of deep layers of cartilage will be beneficial for a number of clinical applications, such as laser technologies used for cartilage regeneration and reshaping. Since cartilaginous tissue absorbs the mechanical loads of body movement and the safety of its mechanical properties is of the utmost importance, special attention is paid to mechanical stresses induced by the application of hyperosmotic optical clearing agents (OCAs) and methods for their noncontact evaluation and quantification. The abilities of phase-resolved optical coherent elastography (OCE) for spatiotemporal monitoring of local strain in cartilage, induced by osmotic pressure, are introduced and demonstrated in detail. The newly revealed phenomenon of strain sign change under the action of hyperosmotic OCA and its concentration dependence are discussed.
