Hydrogels as a Replacement Material for Damaged Articular Hyaline Cartilage

Abstract

Hyaline cartilage is a strong durable material that lubricates joint movement. Due to its avascular structure, cartilage has a poor self-healing ability, thus, a challenge in joint recovery. When severely damaged, cartilage may need to be replaced. However, currently we are unable to replicate the hyaline cartilage, and as such, alternative materials with considerably different properties are used. This results in undesirable side effects, including inadequate lubrication, wear debris, wear of the opposing articular cartilage, and weakening of the surrounding tissue. With the number of surgeries for cartilage repair increasing, a need for materials that can better mimic cartilage, and support the surrounding material in its typical function, is becoming evident. Here, we present a brief overview of the structure and properties of the hyaline cartilage and the current methods for cartilage repair. We then highlight some of the alternative materials under development as potential methods of repair; this is followed by an overview of the development of tough hydrogels. In particular, double network (DN) hydrogels are a promising replacement material, with continually improving physical properties. These hydrogels are coming closer to replicating the strength and toughness of the hyaline cartilage, while offering excellent lubrication. We conclude by highlighting several different methods of integrating replacement materials with the native joint to ensure stability and optimal behaviour.

Tough and Low Friction Polyvinyl Alcohol Hydrogels Loaded with Anti-inflammatories for Cartilage Replacement

“…AC is a connective tissue present on the articular surfaces that, although tough and flexible, may suffer wear over the years or be damaged by injury or accidents. Due to its avascular and aneural structure, AC is not capable of developing a normal inflammatory response, and its ability for self-repair is quite limited [1,2]. Depending on the nature and extent of the damage, different strategies may be followed to recover its function.…”

In Situ Polyphosphate Nanoparticle Formation in Hybrid Poly(vinyl alcohol)/Karaya Gum Hydrogels: A Porous Scaffold Inducing Infiltration of Mesenchymal Stem Cells

“…They are suitable for fabrication of bioinspired scaffold materials in tissue engineering bone and cartilage. [29,30]). [26] The polyP nanoparticles can also be fabricated in hybrid forms, e.g., with N,O-carboxymethyl chitosan [27] or with hyaluronic acid [8] ; the nanoparticles retain their biological function.…”

Tribological behaviour, mechanical properties and bio-interface engineering of bio-inspired hydrogels

“…Articular cartilage plays a crucial role in protection of bones, however due to its avascular nature, self-healing of the cartilage after severe damage or joint aging is very limited . The materials currently used for joint-replacement are mostly engineered materials, such as cobalt chrome (CoCr) alloys, zirconia, alumina and ultra-high molecular weight polyethylene (Beddoes et al, 2016). The advantage of these materials is that they have sufficient mechanical stiffness to support applied loads.…”

“…(Hughes, 2004) compared with manufactured hydrogels, including PVA/PAAm (Li et al, 2014), PAAm/Alginate (JeongYun et al, 2012), PAAm/MMT (Gao et al, 2015), PAMPSA (Xing et al, 2014), Polyampholytes (Sun et al, 2013), Carboxybetaine acrylamide (Bai et al, 2014), and Polyion complexes (Luo et al, 2015). Reproduced from Beddoes et al (2016).…”

“…Articular cartilage (AC) can accomplish remarkable low friction under various conditions to protect bones, which is enabled by a combination of modes of fluid-film lubrication and boundary lubrication(McNary et al, 2012). Current development of cartilage-mimetic materials highlight hydrogel as an alternative material mainly because of its potential to mimic the mixed lubrication mechanism of AC, yet applications are still challenging due to lack of mechanical toughness(Beddoes et al, 2016).To overcome the current challenges, I have turned to seek inspiration from other natural materials. The tribological phenomena in plants are equally remarkable as those in animal kingdom; in order to enable plant growth, tribological contact is mediated by pectin-rich middle lamella where a relative sliding must occur between adjacent cell walls under high turgor pressure during plant growth (Cosgrove, 2005).…”