Artificial Cartilage Material Research Articles

Full Regional Creep Displacement Map of Articular Cartilage Based on Nanoindentation Array.

The elucidation of the mechanisms underlying articular cartilage lesions poses a formidable challenge in the field of cartilage repair. Despite significant strides in cartilage mechanics research, the region-dependent creep properties of articular cartilage remain elusive. In this study, we employ depth-sensing indentation tests to experimentally determine the creep properties of four distinct regions of articular cartilage, thereby unveiling a region-dependent full map of creep parameters. The measured creep displacement-time response curves indicate that the creep properties of the articular cartilage exhibit a clear regional correlation. Accordingly, the full regional creep map of articular cartilage is experimentally constructed for the first time. The correlation between the microstructures and the creep properties of cartilage in different regions is revealed. A three-parameter model is established to describe the creep velocity-displacement response of cartilage. Raman spectra reveal that the proteoglycan content is positively correlated with creep properties. The Raman shift directly indicates diverse residual stresses in different microregions. The obtained data facilitate a deep understanding of the potential creep dependent damage mechanism of cartilage and the further development of artificial cartilage materials.

Water loss and defects dependent strength and ductility of articular cartilage

Water loss and surface defects of articular cartilage extremely aggravate the risk of osteoarticular diseases. The effects of water content and surface defects on the mechanical properties of cartilage need to be taken into further account. By using a self-developed in-situ tensile tester, the tensile stress-strain relationship and real-time morphological changes under conditions of different water contents are obtained with and without a micro void. It is confirmed that tissue structure and permeability are the main factors affecting the strength and ductility of cartilage. The less water content contributes to the lower permeability, inducing higher strength but poorer plasticity. Raman spectroscopy analysis results directly reveal the transition from the bonding water with stronger hydrogen bonds to the free water with weaker hydrogen bonds in cartilage layer caused by both drying treatment and tensile deformation, which results in decreased permeability and enhanced resistance to deformation. Raman-based organic matrix content is negatively correlated with permeability but positively correlated with the strength of cartilage. The obtained experimental data may facilitate to predict cartilage damage and develop artificial cartilage materials.

Mussel-inspired construction of Ti6Al4V-hydrogel artificial cartilage material with high strength and low friction

Based on the adhesion mechanism of polydopamine, the mussel-inspired hydrogel was prepared on the surface of the Ti6Al4V (Ti) with polydopamine (PDA), polyvinyl alcohol (PVA), hydroxyapatite (HA) and polyacrylic acid (PAA) as raw materials in this study, and the Ti-hydrogel artificial cartilage material was constructed. The hydrogel exhibited a tensile strength of 11.76 MPa, an elongation of 988.76%, and a creep deformation of only 0.035 mm under a 20 N load. The friction coefficient of the Ti6Al4V-hydrogel (Ti-hydrogel) artificial cartilage material decreased and the friction performance was improved. After the substrate was modified by the PDA, the bonding strength of the substrate to the hydrogel up to 6.64 MPa. Therefore, the mussel-inspired hydrogel is an ideal high-strength biomimetic cartilage material.

Development and Characterization of a Poly (Vinyl Alcohol)/Graphene Oxide Composite Hydrogel as An Artificial Cartilage Material

Poly (vinyl alcohol) hydrogel (PVA-H) is expected to be a suitable artificial articular cartilage material because of its high biocompatibility. However, it is difficult to affix to the surface of a living joint because it is bioinert and its mechanical strength needs to be improved. In this study, graphene oxide (GO) subjected to two oxidation rounds was used to form a nanocomposite material and the composite hydrogel PVA-GO-H was prepared by low-temperature crystallization. Scanning electron microscope (SEM) images showed that the addition of GO can increase roughness of the hydrogel surface. Contact angle measurements showed that the surface of PVA-GO-H exhibited hydrophobicity that increased with GO concentration and not with that of PVA-H, indicating that the hydrophilic parts of PVA and GO form hydrogen bonds and the hydrophobic part of GO was exposed on the surface. Tensile tests demonstrated that Young’s modulus was enhanced on the addition of GO. Osteoblast cells showed more affinity for PVA-GO-H than PVA-H, which much more cells adhere to than to PVA-GO-H after a certain period of culturing, suggesting GO can improve the cell attachment of PVA-H. Further studies on the influence of the oxidation time of GO are still required.

Reinforcement of poly(vinyl alcohol) hydrogel with halloysite nanotubes as potential biomedical materials

ABSTRACTThis work reports the reinforcement of poly(vinyl alcohol) (PVA) hydrogel with halloysite nanotubes (HNT) as potential biomedical materials. The nanocomposite hydrogel was prepared using the facile and harmless process of freeze–thawing. Mechanical properties of the hydrogels were optimum at 2 wt% of HNT loading. Morphological and topographic analysis of the PVA/HNT hydrogel revealed excellent filler dispersion and smoothing of surface due to good compatibility between the components. Immersion of the PVA/HNT hydrogel in simulated body fluid for 7 days resulted in the formation of fully covered apatite layers on the surface. This is a good indication of bioactivity for artificial cartilage material.

Evaluation of lubrication properties of hydrogel artificial cartilage materials for joint prosthesis

Abstract Poly (vinyl alcohol) (PVA) hydrogel with high water content is the candidate material for artificial cartilage. PVA hydrogels prepared by freeze-thawing (FT) method (PVA-FT gel), cast-drying (CD) method (PVA-CD gel) and hybrid method of FT and CD (PVA-hybrid gel) were developed and their friction and wear behaviors were evaluated. Sliding pairs of a cobalt-chromium-molybdenum alloy or alumina ceramic ball and a PVA hydrogel plate were tested in reciprocating friction test. Ultra-pure water and simulated synovial fluid were used as lubricants for friction test. PVA-FT gel showed high friction and severe wear in ultra-pure water. Friction coefficient of PVA-CD gel in ultra-pure water was quite low such as about 0.005, but scratches were observed on the surface of PVA-CD gel. PVA-hybrid gel lubricated in ultra-pure water showed low friction such as 0.004, and intact surface structure of PVA-hybrid gel remained after friction test. Simulated synovial fluid contributed to the improvement of lubrication property of all PVA hydrogels and PVA-hybrid gel showed the lowest friction coefficient such as 0.003 and minimum wear. These results indicated that PVA-hybrid gel has a great potential as the material for artificial joint.

1G24 繊維強化PVAハイドロゲルの機能向上に関する研究

Articular cartilage plays an important role to realize low friction coefficient in wide operating condition. While there exists several frictional mode to adapt each condition, the role of the biphasic lubrication mode relatively arises in a low sliding speed condition, where the fluid film lubrication mode can not work enough. The PVA hydrogel is expected as an artificial cartilage material, which can contain plenty of water to activate the biphasic lubrication mode. In articular cartilage, the soft gel matrix is reinforced by collagen network structure to resist tensile deformation, in which the tensile stiffness of the biphasic material generates the interstitial fluid pressurization. Higher fluid load support leads lower friction coefficient because the solid-to-solid contact pressure decreases by the increased fluid pressure. In this study, we developed the fiber reinforced PVA hydrogel to enhance the fluid pressure, which can support a considerable proportion of the contact pressure as a load bearing system. The biphasic finite element analysis showed the effective enhancement of the interstitial fluid pressurization in the fiber reinforced PVA hydrogel. The fiber reinforcement maintained the fluid load support in a migrating reciprocal sliding condition. The potential of the biomimetic artificial cartilage was expected as a load bearing material.

1G25 ハイドロゲル人工軟骨候補材料の低摩擦・低摩耗化

1G25 ハイドロゲル人工軟骨候補材料の低摩擦・低摩耗化

Surface Modification of Ultra-High Molecular Weight Polyethylene with Crosslinked Hyaluronic Acid and its Antiwear Performance

The surface of high-pressure crystallized ultra-high molecular weight polyethylene (UHMWPE) was modified for application as an artificial cartilage material. A UHMWPE surface pretreated by a series of processes, including treatment with O2-plasma and ethylenediamine solution, was coated with hyaluronic acid (HA). After that, adipic acid dihydrazide (AAD) was added to partially crosslink the HA coating in order to enhance its durability. The modified samples were verified by water contact angle measurement and Fourier transform infrared spectrometry. Both HA layers, original and crosslinked, were also quantitatively evaluated by carbohydrate chemistry assay according to the absorbance of the incident light. The tribological performance of the samples was evaluated by a pin-on-disk test rig lubricated by normal saline under an average pressure of 18 MPa and at a sliding speed of 0.03 m/s for 45 h. The wear resistance of the HA-coated UHMWPE specimens promoted by the crosslink process was superior to that of the original HA-coated sample, and that resistance was maintained after immersion in saline solution for one month.

聚乙烯醇/壳聚糖复合水凝胶的物理化学性质

The physical properties such as the equilibrium water content, the melting enthalpy, the isothermal swelling kinetics and the non-isothermal dehydration kinetics of the composite hydrogels of poly(vinyl alcohol) (PVA) and chitosan (CS) were determined in this work. The influence of the composition and preparation parameters of the hydrogels on these properties was discussed. The results indicate that, PVA/CS composite hydrogel have a proper network structure to support water, and to work as an artificial cartilage material. Combining CS and PVA leads the crystallinity of gel to be weakened, but the interaction between water and gel scaffold to be enhanced. Though the mechanical tensile strength was lowered, but the biocompatibility and the degradation capacity of the gel were optimized. As a class of biomedical functional materials, PVA/CS hydrogel has a great potential application in cartilage scaffold. And as a model system of theoretical research, it promotes the application of thermodynamics in biomedical functional materials.

Hydrogel formation from the concentrated aqueous solution of polyvinyl alcohol

ABSTRACTPhysically crosslinked polyvinyl alcohol (PVA) hydrogels with high mechanical properties can be made by a low temperature crystallization method using a mixed solvent of dimethyl sulfoxide (DMSO) and water. Such hydrogels are studied as the artificial articular cartilage material. But DMSO shows cytotoxycity, and it is also have the effect of accelerating the absorption of harmful substances. Therefore completely elimination must be required for clinical application but the process is difficult.However, PVA hydrogel made by water as a sole solvent by freeze-thawing method became cloudy because of micro-heterogeneous structure, and shows low mechanical properties.Therefore, in this study, we developed the novel hot pressing method for preparing transparent and uniformly cross-linked PVA hydrogels without DMSO from highly concentrated aqueous solution. By this method, PVA hydrogels with high mechanical property and high transparency can be obtained without any harmful organic solvent because of the fast crystallization even at room temperature. The mechanical properties of PVA hydrogels were remarkably depended on their water contents after gelation, regardless of solution concentration.

Influence of Phospholipid and Protein Constituents on Tribological Properties of Artificial Hydrogel Cartilage Material

Influence of Phospholipid and Protein Constituents on Tribological Properties of Artificial Hydrogel Cartilage Material

8B-14 関節液中のリン脂質成分が人工軟骨候補材料の摩擦・摩耗挙動に与える影響(OS-2(1) 人工関節のバイオエンジニアリング(2))

8B-14 関節液中のリン脂質成分が人工軟骨候補材料の摩擦・摩耗挙動に与える影響(OS-2(1) 人工関節のバイオエンジニアリング(2))

0931 人工軟骨候補材料の摩擦に与える蛋白質二次構造の影響(OS20-1:人工関節とバイオエンジニアリング1)

0931 人工軟骨候補材料の摩擦に与える蛋白質二次構造の影響(OS20-1:人工関節とバイオエンジニアリング1)

J0204-1-1 蛋白質吸着膜の摩擦に与える二次構造の影響([J0204-1]バイオトライボロジー(1))

The influence of protein on friction of artificial cartilage material has been investigated to improve the friction and wear property. In this study the influence of secondary structure of adsorbed protein on friction was evaluated in a reciprocating friction tester. As a result, coefficient of friction depended on the ratio of content of β-sheet structure to that of random coil. It is supposed that the secondary structure of adsorbed protein is effective to control friction of PVA hydrogel.

Control of proliferation and differentiation of osteoblasts on apatite‐coated poly(vinyl alcohol) hydrogel as an artificial articular cartilage material

One of the key challenges in employing biomaterials is determining how to fix them into the surrounding tissue. To enhance the interaction with surrounding bone, amorphous hydroxyapatite (HA) was coated onto the surface of the bio-inert poly(vinyl alcohol) hydrogel (PVA-H), as an artificial cartilage material, by a pulsed laser deposition technique. Next we examined the binding effects of the HA thin film (300 nm thick) to the underlying bone using osteoblast proliferation and differentiation. A mouse osteoblast cell line, MC3T3E1, was cultured on the HA-coated and noncoated PVA-H with a water content of 33% or 53% for 3 weeks. Cell proliferation, alkaline phosphatase (ALP) activity, and levels of osteocalcin were evaluated for biocompatibility and differentiation. HA coating enhanced the cell proliferation, the ALP activity, and the levels of osteocalcin on both low and high water-content PVA-Hs. The cell growth rates on the PVA-H were lower than on tissue culture dishes even after the HA coating was added; however, osteoblastic differentiation was highly promoted by the HA coating on low water content PVA-H. These results suggested that the HA coating on the PVA-H enhanced the affinity between the bone and the PVA-H as an artificial cartilage material in surface replacement arthroplasty.

Tribological properties of polyvinyl alcohol hydrogel reinforced with nanometer hydroxy apatite

As a potential artificial cartilage material, the friction and wear properties of nano-hydroxy apatite (HA) particles filled poly (vinyl alcohol) hydrogel (PVA-H) composites sliding against stainless steel disk under water lubrication condition were studied by using a four ball tester. The worn surfaces were investigated by using a scanning electron microscope (SEM) to determine the wear mechanisms. Experimental results show that filling HA to PVA-H will slightly increase the friction coefficient of composites with the increasing of HA content under water lubrication condition. Meanwhile, HA particles can greatly reduce the wear mass loss of the PVA-H composites and enhance the load carrying capacity, the wear loss of the 1 wt% HA reinforced PVA-H composites can be decreased by 30 percent under 2.0 MPa to 50 percent under 0.5 MPa contact pressure. We also found that 2 wt% HA content of composites increase the wear mass loss under the same condition. SEM examination shows that the worn surface of low HA containing (1 wt%) composites are much smoother than that of pure PVA-H or high HA containing (2 wt%) composites under 1.5 MPa contact pressure. It is also found that there are big hole and big reunited HA particles in the surface of 2 wt% HA containing composites, which leads to deterioration of the surface of samples under higher loads in water lubrication. These results may be useful in the tribological design of artificial articular cartilage material.

OS2-1-2 Mechanisms of Protein Boundary Film Formation for Poly (vinyl alcohol) Hydrogel as Artificial Cartilage Material

OS2-1-2 Mechanisms of Protein Boundary Film Formation for Poly (vinyl alcohol) Hydrogel as Artificial Cartilage Material

The effect of the conformational changes of proteins on the frictional properties in an artificial cartilage material

The effect of the conformational changes of proteins on the frictional properties in an artificial cartilage material

Bio-mimetic study of novel materials for joint replacements

AbstractPolytrimethylene carbonate (PTMC) and poly ε-caprolactone are conventional biodegradable, biocompatible polymers. Their friction response against cartilage and surface attraction forces were studied toward using them as artificial cartilage materials. Their behavior was compared to that of natural cartilage and a conventional joint replacement material, ultrahigh molecular weight polyethylene. It was possible to polymerize these materials using a calcium based catalyst. Simulated body fluid (SBF) was used as lubricant between surfaces in the friction tests. It was found that higher surface attractive forces on a silicon tip AFM related to lower friction coefficients. This confirs the fact that hydrophilic surfaces enhance the effectiveness of boundary lubrication of simulated body fluid. PTMC and PTMC-ε-caprolactone co-polymer showed lower hydrophilicity and higher friction coefficients and need to be modified in order to bring them closer in behavior to natural cartilage.