Osmotic pressure characterization of glycosaminoglycans using full-atomistic molecular models

Abstract

The osmotic pressure of chondroitin sulfate glycosaminoglycans (CS-GAGs) in a simulated physiological environment of articular cartilage is thoroughly examined in silico using full atomistic models. The effects of chemical and physical properties were investigated to elucidate the molecular origins of cartilage biomechanical behavior providing singleatomistic resolution analyses which would not be attainable with in vivo or in in vitro techniques. CS-GAG chains exhibit plastic deformation behavior under compressive load in the extracellular matrix (ECM) and osmotic pressure is the main contributor in balancing external pressures. This study focuses on quantitatively expressing this contribution.Molecular dynamics was used to imitate the physiological environment experienced by

Osmotic gradients and transretinal water flow—a quantitative elemental microanalytical study of frozen hydrated chick eyes

“…Lastly, our analysis suggests that the cartilaginous layer of the sclera is possibly hyperosmotic to the choroid, due to the high scleral concentrations of S and Na found here and in typical cartilage that consists of abundant sulfated glycosaminoglycan. These highly negatively charged glycosaminoglycan chains are known to interact with Na in the interstitial fluid to form a Donnan osmotic pressure that resists compressive forces on the cartilage (Pando et al, 2017 ) and is hyperosmotic to the choroid. In chickens the cartilage has been shown to have an increased glycosaminoglycan content in response to induced myopia (Rada et al, 1991 ; Nickla et al, 1997 ), suggesting that the cartilage may absorb more water by osmosis.…”