Towards the Development of a Cartilage-like Nanofiber-Hydrogel Composite

MRS Advances ◽  
2020 ◽  
Vol 5 (33-34) ◽  
pp. 1783-1790
Author(s):  
Jacob M. Ludwick ◽  
Michelle L. Oyen

ABSTRACTArticular cartilage plays an important role in synovial joint function, but this function is diminished when cartilage tissue breaks down in osteoarthritis. Tissue engineering is a promising approach for replacing failed cartilage, as cartilage is a relatively simple tissue with no blood supply and very few biological cells. To imitate the structure of natural cartilage extracellular matrix material, three components must be included: the hydrated ground substance, the charges that contribute to compressive stiffness via electrostatic repulsion, and the nanofibrous collagen network that resists tensile deformation and failure. Here, the nanofiber network is considered, with examination of its fracture behavior in an as-electrospun state and following a mild chemical crosslinking process. Mode III fracture testing was used to quantify the tear toughness of the fibrous mats, and failure behavior was qualitatively examined with scanning electron microscopy. In ongoing work, this nanofibrous structure will be combined with a charged polyelectrolyte hydrogel gel to create a biomimetic cartilage-like material. By using biomimicry to replicate what is present in native cartilage tissue, a superior material can be designed and fabricated for use in tissue repair and replacement.

2010 ◽  
Vol 51 (4) ◽  
pp. 699-706 ◽  
Author(s):  
Shojiro Ochiai ◽  
Satoshi Nakano ◽  
Yuya Fukazawa ◽  
Mohamed Shehata Aly ◽  
Hiroshi Okuda ◽  
...  

2021 ◽  
Vol 2085 (1) ◽  
pp. 012039
Author(s):  
Pengjing Zhao ◽  
Jingpin Jiao ◽  
Gang Fang ◽  
Zhanghua Chen ◽  
Xiang Gao

Abstract A VUMAT user material subroutine for the Lemaitre continuous damage mechanics model was developed based on the finite element solver ABAQUS/Explicit platform to investigate the deformation and failure behavior of 5052 aluminum alloy. The mechanical property parameters and damage parameters of 5052 aluminum alloy were identified by the inversion method combining tensile test and finite element simulation. The numerical simulation results showed that the force-displacement curves predicted by the established damage model were in good agreement with the experimental measurement, and the fracture location was close to the experimental results, which verified the accuracy and effectiveness of the damage parameters. The growth and distribution law of damage variable could be intuitively represented by the simulation results by the Lemaitre damage model.


Author(s):  
Andrew Lees ◽  
Michael Dobie

Polymer geogrid reinforced soil retaining walls have become commonplace, with routine design generally carried out by limiting equilibrium methods. Finite element analysis (FEA) is becoming more widely used to assess the likely deformation behavior of these structures, although in many cases such analyses over-predict deformation compared with monitored structures. Back-analysis of unit tests and instrumented walls improves the techniques and models used in FEA to represent the soil fill, reinforcement and composite behavior caused by the stabilization effect of the geogrid apertures on the soil particles. This composite behavior is most representatively modeled as enhanced soil shear strength. The back-analysis of two test cases provides valuable insight into the benefits of this approach. In the first case, a unit cell was set up such that one side could yield thereby reaching the active earth pressure state. Using FEA a test without geogrid was modeled to help establish appropriate soil parameters. These parameters were then used to back-analyze a test with geogrid present. Simply using the tensile properties of the geogrid over-predicted the yield pressure but using an enhanced soil shear strength gave a satisfactory comparison with the measured result. In the second case a trial retaining wall was back-analyzed to investigate both deformation and failure, the failure induced by cutting the geogrid after construction using heated wires. The closest fit to the actual deformation and failure behavior was provided by using enhanced fill shear strength.


2000 ◽  
Vol 116 (7) ◽  
pp. 565-571 ◽  
Author(s):  
Yasuyuki FUJITA ◽  
Yoshiaki FUJII ◽  
Yoji ISHIJIMA

2021 ◽  
Author(s):  
Weiping Lin ◽  
Zhengmeng Yang ◽  
Liu Shi ◽  
Haixing Wang ◽  
Qi Pan ◽  
...  

Abstract Background: Osteoarthritis (OA) is a chronic joint disease, characterized by articular cartilage degradation, subchondral bone hardening, and inflammation of the whole synovial joint. There is no pharmacological treatment in slowing down OA progression, leading to costly surgical interventions eventually. Cell therapy using chondrocytes or progenitor cells from different sources has been reported in clinical trials for OA management with some success, but outcomes are varied. Peripheral blood derived mesenchymal stem cells (PB-MSCs) are promising cells owing to their easy collection, superior migration, and differentiation potentials. In the current study, we evaluated the effect of intra-articular administration of PB-MSCs on the progression of OA in mice.Methods: C57BL/6J mice (8-10 weeks old male) were subjected to destabilization of the medial meniscus surgeries (DMM) on their right joints following protocols as previously reported. The mice after DMM were randomly treated with saline (vehicle control), PB-MSCs, or adipose tissue derived MSCs (AD-MSCs) (n = 7 per group). The mice treated with sham surgery were regarded as sham controls (n = 7). PB-MSCs and AD-MSCs were harvested and cultured according to previous published protocols, and pre-labeled with BrdU for 48 h before use. PB-MSCs or AD-MSCs (5 × 105 cells/mouse; passage 3~5) were injected into the right knee joints thrice post-surgery (except sham surgery group). The mice were euthanized at 8 weeks post-surgery and knee joint samples were collected for micro-CT and histological examinations.Results: PB-MSCs administration significantly reduced hardening of subchondral bone comparing to vehicle controls. Safranin O staining showed that PB-MSCs treatment ameliorated degeneration of articular cartilage, which is comparable to AD-MSCs treatment. The expression of catabolic marker MMP13 was significantly reduced in articular cartilage of PB-MSCs-treated groups comparing to vehicle controls. Co-expression of BrdU and Sox9 were detected, indicating injected PB-MSCs differentiated towards chondrocytes in situ. Reduced level of IL-6 in the peripheral sera of PB-MSCs- and AD-MSCs-treated mice was also determined. Conclusions: Repetitive administration of PB-MSCs or AD-MSCs halted OA progression through inhibiting cartilage degradation and inflammation. PB-MSCs may become a promising cell source for cartilage tissue repair and alleviation of OA progression.


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