Recent Progress in Hydrogel-Based Synthetic Cartilage: Focus on Lubrication and Load-Bearing Capacities

Abstract

Articular cartilage (AC), which covers the ends of bones in joints, particularly the knee joints, provides a robust interface to maintain frictionless movement during daily life due to its remarkable lubricating and load-bearing capacities. However, osteoarthritis (OA), characterized by the progressive degradation of AC, compromises the properties of AC and thus leads to frayed and rough interfaces between the bones, which subsequently accelerates the progression of OA. Hydrogels, composed of highly hydrated and interconnected polymer chains, are potential candidates for AC replacement due to their physical and chemical properties being similar to those of AC. In this review, we summarize the recent progress of hydrogel-based synthetic cartilage, or cartilage-like hydrogels, with a particular focus on their lubrication and load-bearing properties. The different formulations, current limitations, and challenges of such hydrogels are also discussed. Moreover, we discuss the future directions of hydrogel-based synthetic cartilage to repair and even regenerate the damaged AC.

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

“…Among all those biomaterials, hydrogel-based cartilage lubricants within one or several lubricating mechanisms have gained rapid development for their excellent biocompatibility, tunable physical properties, and structural similarity to human tissues. [19,[39][40][41] Intra-articular HA injections are FDA-approved for OA symptom relief, but their short duration and frequent administration pose challenges. The need for a carrier system to prolong HA release and degradation in the joint is emphasized.…”

“…Many bio‐lubricants including polymer brushes, hydrogels, and nanoparticles (NPs) for joint cartilage have been reported utilizing one or more lubricating mechanisms. Among all those biomaterials, hydrogel‐based cartilage lubricants within one or several lubricating mechanisms have gained rapid development for their excellent biocompatibility, tunable physical properties, and structural similarity to human tissues [19, 39–41] …”

Influence of Nanoparticle Chemical Composition on <i>In Situ</i> Hydrogel Friction

“…Given the vast range of possibilities for nanoparticles, additional reviews have highlighted numerous studies including organic and inorganic based nanoparticles effective in direct therapeutics and as delivery systems [7][8][9] What is lacking from many of these studies, however, is the consideration of joint movement and the impact of nanoparticle additives on sliding. An extensive collection of literature examines joint friction [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] and mimetic materials such as hydrogels [26][27][28][29][30][31][32] (note the literature cited here is not a comprehensive list), yet few connect nanoparticles in synovial joints to sliding, and tend to focus on polymeric-based nanoparticles. In simulations by Jamalabadi [13] hollow silica nanoparticles with core/shell charged polymer brushes were evaluated in a modeled knee, finding that an increase in nanoparticle concentration decreased the maximum pressure on the squeeze film.…”