Research progress of cartilage lubrication and biomimetic cartilage lubrication materials

Abstract

Human joints move thousands of times a day. The articular cartilage plays a vital role in joints’ protection. If there is dysfunction in cartilage lubrication, cartilage cannot maintain its normal function. Eventually, the dysfunction may bring about osteoarthritis (OA). Extensive researches have shown that fluid film lubrication, boundary lubrication, and hydration lubrication are three discovered lubrication models at cartilage surface, and analyzing and simulating the mechanism of cartilage lubrication are fundamental to the treatment of OA. This essay concludes recent researches on the progress of cartilage lubrication and biomimetic cartilage, revealing the pathophysiology of cartilage lubrication and updating bio-inspired cartilage lubrication applications.

Hydrogels for ameliorating osteoarthritis: Mechanical modulation, anti‐inflammation, and regeneration

“…Previous studies have shown that enhanced synovial fluid lubrication between cartilage surfaces is associated with the alleviation of OA. [23,24] Among a variety of biomaterials, hydrogels that are polymer networks with high water content and excellent physicochemical properties, such as self-healing, shear thinning, and viscoelastic capacities, demonstrate great prospects in joint lubrication. [22] By forming a viscous gel layer, the hydrogel can provide a stable lubricating effect, thus reducing joint pain and inflammation.…”

“…[37] However, the prime candidates for boundary lubrication, either by themselves or in combination, exhibit significantly higher boundary friction coefficients compared to those in whole joints at physiological pressures, which means that other lubrication mechanisms are involved in cartilage sliding. [23] Previous reports have indicated that water molecules surrounding an ion in solution can form a hydration shell that can be resistant to shear stress since the water molecule of hydration will not be squeezed out. [38] The introduction of a hydration layer could explain the fact that the low boundary COF existed in the cartilage in a pressured environment (Figure 1c).…”

“…With early intervention and appropriate management strategies, it is possible to potentially slow down the disease progression and provide symptomatic relief. Previous studies have shown that enhanced synovial fluid lubrication between cartilage surfaces is associated with the alleviation of OA [23,24] . Among a variety of biomaterials, hydrogels that are polymer networks with high water content and excellent physicochemical properties, such as self‐healing, shear thinning, and viscoelastic capacities, demonstrate great prospects in joint lubrication [22] .…”

Bioinspired Supramolecular Hydrogel from Design to Applications

“…This combination provides cartilage with compressive and tensile strength, lubrication, and ensures its survival and function in the mechanical pressure environment of the joint. [252] Inspired by the high mechanical strength and self-healing ability of cartilage tissue, [253][254][255] a novel supramolecular polymer double network gel (PS-DN gel), has been proposed. [256] The design of this hydrogel is based on the features of articular cartilage, where glycosaminoglycan chains are bound or assembled onto the backbone of hyaluronic acid, forming a polymer network with a molecular weight of up to 200 MDa, while collagen forms a supramolecular fiber network.…”

“…This combination provides cartilage with compressive and tensile strength, lubrication, and ensures its survival and function in the mechanical pressure environment of the joint. [ 252 ]…”