There are three varieties of cartilage-hyaline, elastic, and fibrocartilage. Hyaline cartilage is the precursor of bone. In the adult it is mainly found at bone ends, forming the load-bearing surface of synovial joints. Extra-articular fibrocartilages such as those of the trachea and ribs often calcify with advancing age. Articular cartilage, however, usually remains free from mineral deposits....

Electrostatic interactions associated with aggrecan, one of the major components of the cartilage extracellular matrix, are responsible for ~50% of the equilibrium compressive elastic modulus of the tissue. The bottle-brush-shaped aggrecan consists of a core protein to which ~100 sulfated glycosaminoglycan (sGAG) chains are attached. Loss of sGAG is one early events in the pathogenesis of osteo...

OBJECTIVES Laser reshaping of cartilage is an emerging technology aimed at replacing conventional techniques for aesthetic and reconstructive surgery. Little is known about the mechanisms of wound healing following the photothermal heating during laser reshaping and, ultimately, how collagen remodels in the irradiated tissue. Healthy hyaline and elastic cartilage as found in the ear, nose, lary...

The atomic force microscope (AFM) has found wide applicability as a nanoindentation tool to measure local elastic properties of soft materials. An automated approach to the processing of AFM indentation data, namely, the extraction of Young's modulus, is essential to realizing the high-throughput potential of the instrument as an elasticity probe for typical soft materials that exhibit inhomoge...

In this study, atomic force microscopy-based dynamic oscillatory and force-relaxation indentation was employed to quantify the time-dependent nanomechanics of native (untreated) and proteoglycan (PG)-depleted cartilage disks, including indentation modulus E(ind), force-relaxation time constant τ, magnitude of dynamic complex modulus |E(∗)|, phase angle δ between force and indentation depth, sto...

The development of hydrogels for cartilage replacement and soft robotics has highlighted a challenge: load-bearing hydrogels need to be both stiff and tough. Several approaches have been reported to improve the toughness of hydrogels, but simultaneously achieving high stiffness and toughness remains difficult. Here we report that alginate-polyacrylamide hydrogels can simultaneously achieve high...