Triborheological Study under Physiological Conditions of PVA Hydrogel/HA Lubricant as Synthetic System for Soft Tissue Replacement

Abstract

In soft tissue replacement, hydrophilic, flexible, and biocompatible materials are used to reduce wear and coefficient of friction. This study aims to develop and evaluate a solid/liquid triborheological system, polyvinyl alcohol (PVA)/hyaluronic acid (HA), to mimic conditions in human synovial joints. Hydrogel specimens prepared via the freeze–thawing technique from a 10% (w/v) PVA aqueous solution were cut into disc shapes (5 ± 0.5 mm thickness). Compression tests of PVA hydrogels presented a Young’s modulus of 2.26 ± 0.52 MPa. Friction tests were performed on a Discovery Hybrid Rheometer DHR-3 under physiological conditions using 4 mg/mL HA solution as lubricant at 37 °C. Contact force was applied between 1 and 20 N, highlighting a coefficient of friction change of 0.11 to 0.31 between lubricated and dry states at 3 N load (angular velocity: 40 rad/s). Thermal behavior was evaluated by differential scanning calorimetry (DSC) in the range of 25–250 °C (5 °C/min rate), showing an endothermic behavior with a melting temperature (Tm) around 231.15 °C. Scanning Electron Microscopy (SEM) tests showed a microporous network that enhanced water content absorption to 82.99 ± 1.5%. Hydrogel achieved solid/liquid lubrication, exhibiting a trapped lubricant pool that supported loads, keeping low coefficient of friction during lubricated tests. In dry tests, interstitial water evaporates continuously without countering sliding movement friction.

An investigation on tribological behavior of methacrylated κ-carrageenan and gellan gum hydrogels as a candidate for chondral repair

“…The surfaces of the hydrogels were smooth and largely homogenous except the presence of inclusions observed in both hydrogels and surface cracks found in only GG-MA-H. The inclusions such as dust particles possibly adhered to the surfaces from the environment, as reported for PVA hydrogel by Duque-Ossa et al 82 While the presence of shallow cracks could be attributed to the brittle nature of GG-MA-H. The effect of load and lubricant on the wear track microscopic morphologies of the hydrogels are shown in Figures 8(c) to (f).…”

Triborheological Analysis of Reconstituted Gastrointestinal Mucus/Chitosan:TPP Nanoparticles System to Study Mucoadhesion Phenomenon under Different pH Conditions

“…Instead, under neutral pH conditions (pH = 6 and 7), mucus behaves as a viscous polymeric solution with an initial dominance of the loss modulus (G ) at very low frequencies followed by a modulus crossover to storage modulus (G ) dominance around an angular frequency of 1 rad/s. This performance is typical in solutions that act as weak gels [45]. In this case, the behavior is produced as a result of the different electrostatic interactions that are established among polysaccharide side chains and disulfide bonds (S-S) at the cysteine terminals of mucin molecules, improving the entanglement of the chains and leading to a random coil conformation of mucin molecules that results in enhanced viscosity [40,[46][47][48].…”

Bioinspired Design of a Cartilage-like Lubricated Composite with Mechanical Robustness

“…Currently available alternative materials for artificial joints suffer from severe surface wear and abrasive particle-induced poor biocompatibility during use − due to their hard and nonelastic mechanical characteristics along with the interface stress-concentration effect. Hydrogels are rising as one kind of representative soft material with excellent performance including low surface friction and good biocompatibility. − Such unique features would render hydrogels with great potential to serve as ideal replacement materials for articular cartilages, if they were with good load-bearing capacity. − …”