A Synthetic Hydrogel Composite with a Strength and Wear Resistance Greater than Cartilage

Abstract

Key hurdles for replacing damaged cartilage with an equivalent synthetic construct are the development of a hydrogel with a strength that exceeds that of cartilage and fixation of this hydrogel onto the surface of an articulating joint. This article describes the first hydrogel with a tensile and compressive strength (51 and 98 MPa) that exceeds those of cartilage (40 and 59 MPa), and the first attachment of a hydrogel to a metal backing with a shear strength (2.0 MPa) that exceeds that of cartilage on bone (1.2 MPa). The hydrogel strength is achieved through reinforcement of crystallized polyvinyl alcohol with bacterial cellulose. The high attachment strength is achieved by securing freeze-dried bacterial cellulose to a metal backing with an adhesive and a shape memory alloy clamp prior to infiltration and crystallization of the polyvinyl alcohol. The bacterial cellulose-reinforced polyvinyl alcohol is three times more wear resistant than cartilage over one million cycles and exhibits the same coefficient of friction. These advances in hydrogel strength and attachment enable the creation of a hydrogel-based implant for durable resurfacing of damaged articulating joints.

Emerging polymeric material strategies for cartilage repair

“…Table 5 Recent studies of polymeric hydrogel materials for synthetic cartilage replacements [131][132][133][134][135][136][137][138][139][140][141][142][143][144][145][146][147][148] Study Material…”

“…Cooper, 2016; 145 Cooper, 2017; 146 Makela, 2018 147 PMPC | Means, 2019; 131 Bonyadi, 2021; 132 Demott, 2022; [133][134][135][136] Demott, 2022; 137 Demott, 2022 138 PAMPS/P(NIPAAm-co-AAm) | PAMPS/P(NIPAAm-co-AAm) PAMPS/P(NIPAAm-co-AAm)/PAAm PAMPS/P(NIPAAm-co-AAm)/ PAPTAC PAMPS/P(NIPAAm-co-AAm)/ [PATPAC or PAMPS] Milner, 2018 139 PAMPS/PAAm/PMPC | Milovanovic, 2021 144 PDMA -calcium phosphate | Patel 148 Hyaluronic acid | Xu, 2018 143 PVA -aramid nanofibers | Yang, 2017 140 PAMPS-LAPONITE s /PAAm | Yang, 2020; 141 Zhao, 2022; 142 Bacterial cellulose -PVA -PAMPS |…”

“…Zhao et al illustrated the ability to adhere BC-PVA-PAMPS hydrogels to a titanium anchor (akin to the BioPoly s implant) with a shear strength of 2 MPa, greater than that of cartilage to bone (1.2 MPa). 142 An annealing step was added in the fabrication process to increase the crystallinity of PVA. 142 The resulting annealed BC-PVA hydrogels achieved a compressive modulus of B10 MPa and strength of B98 MPa.…”

“…142 An annealing step was added in the fabrication process to increase the crystallinity of PVA. 142 The resulting annealed BC-PVA hydrogels achieved a compressive modulus of B10 MPa and strength of B98 MPa. However, this was met with a decreased water content from 89% to 46%.…”

Electrospun fibrous membrane reinforced hydrogels with preferable mechanical and tribological performance as cartilage substitutes

“…These methods have a negative impact on treatment outcomes, including high failure rates, weak integration, etc. [4][5][6] Over the past few decades, partial or total joint replacement has become another clinical means of treating osteoarthritis, and synthetic materials such as ultra-high molecular weight polyethylene, titanium alloys, stainless steel and ceramics have been widely used in joint replacement. However, these implants are too stiff with high interfacial contact stress and poor surface lubrication, resulting in stress shielding and severe wear and tear that exhibit extremely high failure rate.…”