Fabrication of Organized Nanofibrous Scaffolds to Mimic the Macroscopic Curvature of the Meniscus: Structure and Mechanics

2012 ◽  
Author(s):  
Matthew B. Fisher ◽  
Elizabeth A. Henning ◽  
John L. Esterhai ◽  
Robert L. Mauck
Keyword(s):  
Tibial Plateau ◽  
Short Length ◽  
Mechanical Anisotropy ◽  
Knee Meniscus ◽  
Novel Technique ◽  
Nanofibrous Scaffolds ◽  
Electrospinning Method ◽  
Insertion Sites ◽  
Macroscopic Orientation ◽  
Spinning Disc

The menisci are crescent-shaped fibrocartilaginous tissues which function to transmit and distribute loads between the femur and tibia of the knee joint. As such, the meniscus experiences complex loads, including tension, compression, and shear. Meniscus function in tension arises from an organized microstructure — bundles of highly aligned collagen circumnavigate the tissue between insertion sites on the tibial plateau (1). These aligned collagen bundles endow the tissue with mechanical properties that are highly anisotropic, and highest in the primary collagen orientation (2). Commercial products to replace the meniscus lack this unique structure and organization (3,4). To address engineering the knee meniscus, we have developed aligned nanofibrous scaffolds that can recapitulate this mechanical anisotropy (5,6). However promising, fibers within these scaffolds are unidirectional, while the fibers within the native tissue have a pronounced c-shaped macroscopic organization. To mimic this macroscopic orientation, we developed a new electrospinning method to collect organized fibers on a planar spinning disc (7). The objective of this study was to quantify the structure and mechanics of nanofibrous scaffolds collected using this novel technique and compare the data to aligned scaffolds obtained from a traditional electrospinning approach. We hypothesized that these circumferentially aligned (CircAl) scaffolds would behave similarly to linearly aligned (LinAl) scaffolds on short length scales, but exhibit marked differences in mechanics as the length scale increased.

Tibial Plateau Symmetry and the Effect of Osteophytosis on Tibial Plateau Angle Measurements

2007 ◽  
Vol 43 (2) ◽  
pp. 93-98 ◽  
Author(s):  
Matthew John Ritter ◽  
Ruby L. Perry ◽  
N. Bari Olivier ◽  
Sun Young Kim ◽  
Loic M. Dejardin
Keyword(s):  
Tibial Plateau ◽  
Cruciate Ligament ◽  
Medial Tibial Plateau ◽  
Cranial Cruciate Ligament ◽  
Novel Technique ◽  
Angle Measurements ◽  
Significant Difference ◽  
Improve Accuracy ◽  
The Face

A novel technique was developed to estimate the caudal medial tibial plateau landmark in the face of osteophytosis to improve accuracy in tibial plateau angle measurements. Using this technique, tibial plateau angles were evaluated in 31 normal dogs before and 8 months after right cranial cruciate ligament transection. There was no significant difference in mean tibial plateau angle before or after induction of osteophytosis. Additionally, it was determined that 90% of dogs had a difference of =2° between right and left tibial plateau angles, which was considered symmetrical.

Engineering Meniscus Form and Function via Multi-Layer Cell-Seeded Nanofibrous Scaffolds With Circumferentially Aligned Fibers

2013 ◽  
Author(s):  
Matthew B. Fisher ◽  
Nicole Söegaard ◽  
John L. Esterhai ◽  
Robert L. Mauck
Keyword(s):  
Morphological Characteristics ◽  
Single Layer ◽  
Complex Loading ◽  
Mechanical Anisotropy ◽  
Cellular Interactions ◽  
Mechanical Reinforcement ◽  
Promising Alternative ◽  
Form And Function ◽  
Nanofibrous Scaffolds

The menisci are crescent-shaped fibrocartilaginous tissues which function to transmit and distribute complex loading patterns between the femur and tibia of the knee joint. Meniscus function in tension arises from highly aligned collagen fibers which run in a circumferential manner between insertion sites on the tibial plateau (1,2). However, the meniscus is often injured, and partial removal of the meniscus represents the most commonly performed orthopaedic surgery, despite the fact that its removal increases the likelihood of osteoarthritis in the long-term (3). Tissue engineered scaffolds have emerged as a promising alternative to replace portions of the damaged meniscus (4). Toward replacement, we have developed aligned nanofibrous scaffolds that can recapitulate the mechanical anisotropy of the meniscus (5,6). More recently, we have developed an approach to replicate the circumferential macroscopic orientation of fibers using a novel electrospinning method (7). However, these organized scaffolds are relatively thin (<1 mm), and so multilayer scaffolds will be required to replicate the anatomic size of the native tissue. Moreover, cellular interactions will be crucial to the long-term function of these scaffolds. Thus, the objective of this study was to evaluate the morphological characteristics and mechanical properties of single layer and multilayer circumferentially aligned (CircAl) scaffolds seeded with mesenchymal stem cells (MSCs) and to compare them to scaffolds featuring linearly aligned (LinAL) fibers. We hypothesized that with increasing time in culture, matrix formed between layers would provide mechanical reinforcement, particularly in CircAl scaffolds where fiber rotation would be more likely to occur.

scholarly journals Magnesium Oxide Nanoparticles Reinforced Electrospun Alginate-Based Nanofibrous Scaffolds with Improved Physical Properties

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
R. T. De Silva ◽  
M. M. M. G. P. G. Mantilaka ◽  
K. L. Goh ◽  
S. P. Ratnayake ◽  
G. A. J. Amaratunga ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Polyelectrolyte Complex ◽  
Mechanical Stability ◽  
Poly Vinyl Alcohol ◽  
Sem Images ◽  
Mgo Nanoparticles ◽  
Nanofibrous Scaffolds ◽  
Electrospinning Method

Mechanically robust alginate-based nanofibrous scaffolds were successfully fabricated by electrospinning method to mimic the natural extracellular matrix structure which benefits development and regeneration of tissues. Alginate-based nanofibres were electrospun from an alginate/poly(vinyl alcohol) (PVA) polyelectrolyte complex. SEM images revealed the spinnability of the complex composite nanofibrous scaffolds, showing randomly oriented, ultrafine, and virtually defects-free alginate-based/MgO nanofibrous scaffolds. Here, it is shown that an alginate/PVA complex scaffold, blended with near-spherical MgO nanoparticles (⌀ 45 nm) at a predetermined concentration (10% (w/w)), is electrospinnable to produce a complex composite nanofibrous scaffold with enhanced mechanical stability. For the comparison purpose, chemically cross-linked electrospun alginate-based scaffolds were also fabricated. Tensile test to rupture revealed the significant differences in the tensile strength and elastic modulus among the alginate scaffolds, alginate/MgO scaffolds, and cross-linked alginate scaffolds (P<0.05). In contrast to cross-linked alginate scaffolds, alginate/MgO scaffolds yielded the highest tensile strength and elastic modulus while preserving the interfibre porosity of the scaffolds. According to the thermogravimetric analysis, MgO reinforced alginate nanofibrous scaffolds exhibited improved thermal stability. These novel alginate-based/MgO scaffolds are economical and versatile and may be further optimised for use as extracellular matrix substitutes for repair and regeneration of tissues.

scholarly journals Organized nanofibrous scaffolds that mimic the macroscopic and microscopic architecture of the knee meniscus

2013 ◽  
Vol 9 (1) ◽  
pp. 4496-4504 ◽  
Author(s):  
Matthew B. Fisher ◽  
Elizabeth A. Henning ◽  
Nicole Söegaard ◽  
John L. Esterhai ◽  
Robert L. Mauck
Keyword(s):  
Knee Meniscus ◽  
Nanofibrous Scaffolds
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