Poly(L-Lactic acid) (PLLA)-based meniscus tissue engineering

Bahçecioğlu, Gökhan
Meniscus is a fibrocartilaginous tissue which plays an important role in joint stability, lubrication, and load bearing and transmission. Meniscal tears are commonly encountered in sports activities, or caused by degeneration of the cartilage with ageing. They lead to pain, loss of work, disturbed biomechanics of the knee and inability to walk or even move the legs. As the meniscal tissue is avascular in the inner portion, injury to this part does not heal by itself, and therefore treatments are needed. In some cases when complex tears occur, the tissue cannot be successfully treated with the conventional methods. Tissue engineering appears to be a promising alternative to treat such complex tears. It includes the application of cells on scaffolds (or cell carriers), and provision of bioactive agents to the site of injury in order to regenerate the damaged tissue. The cells and the bioactive agents are involved in the synthesis of the new tissue, while the scaffold acts as a support to guide the cells until the new tissue is formed, and it is slowly absorbed by the body leaving the new tissue behind. Thus, a natural tissue is generated at the end. Few studies have been reported on the tissue engineering of meniscus, but neither of them was able to completely mimic the meniscus structure, nor could they succeed in constructing scaffolds with sufficiently high tensile properties. In the current in vitro study, a novel 3D construct was proposed, in which the natural tissue is perfectly mimicked. The 3D construct consisted of aligned collagen fibers embedded within a foam network which stabilizes the structure. The foam was prepared by freezing a polymer solution with a certain concentration, and lyophilizing it. Aligned fibers were aimed to improve the tensile properties. The construct was impregnated in alginate gel, which was then crosslinked, to improve the compressive properties. The foam was prepared from (poly(L-lactic acid)/poly(lactic-co-glycolic acid) (PLLA/PLGA) solutions of various concentrations (2%, 2.5%, 3%, and 4% w/v) and at different freezing temperatures (-20oC or -80oC) to select the best preparation condition. After analysis of the microstructure and mechanical properties, foams prepared from 3% polymer solution frozen at -20oC were found to be the most appropriate for use as scaffold for the 3D construct, since they had large pores, high and interconnected porosity, as well as high mechanical strength. The 3D constructs were seeded with human meniscus cells and incubated for 21 days. Cell behavior on the constructs was examined. Cell attachment and proliferation was found to be better with the constructs not coated with alginate. However, the constructs coated with alginate demonstrated higher compressive strength. It was also found that incorporation of collagen fibers significantly improved the tensile properties. All the constructs were shown to lead to the production of extracellular components specific for fibrocartilages, and thus it was concluded that they were promising for use in meniscal replacement.


Collagen Based Multilayer Scaffolds for Meniscus Tissue Engineering: In Vivo Test Results. Biomater Med Appl 2: 1
Albana Ndreu, Halili; Karahan, Siyami; Kürüm, Barış; Hasırcı, Vasıf Nejat (2018-04-01)
Meniscus is an important component of the knee joint since it performs several crucial functions such as shock absorption, load bearing and transmission, maintenance of joint stability, and lubrication. The results of common meniscal injury repair approaches are not fully satisfactory with low mechanical properties and long regeneration times. A 3D collagen-based construct consisting of multilayers of lyophilized sponges separated by electrospun fibrous mats was prepared previously to serve as a substitute ...
Collagen-based meniscus tissue engineering: design and application
Halili Ndreu, Albana; Hasırcı, Nesrin; Hasırcı, Vasıf Nejat; Department of Biotechnology (2011)
Meniscus is a wedge shaped structure, with a convex base attached to a flat tibial surface, and with a concave femoral surface, on which femur and tibia articulate. It has several functions including joint lubrication, shock absorption, load transmission and joint stability. Various methods were tried to treat meniscal tears but each has its own drawbacks. Tissue engineering seems to be a promising solution that avoids all the problems associated with the other approaches. In this study, a three dimensional...
Acoustic radiation from a fluid-filled, subsurface vascular tube with internal turbulent flow due to a constriction
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The vibration of a thin-walled cylindrical, compliant viscoelastic tube with internal turbulent flow due to an axisymmetric constriction is studied theoretically and experimentally. Vibration of the tube is considered with internal fluid coupling only, and with coupling to internal-flowing fluid and external stagnant fluid or external tissue-like viscoelastic material. The theoretical analysis includes the adaptation of a model for turbulence in the internal fluid and its vibratory excitation of and interac...
Fatigue behavior of Ti-6Al-4V foams processed by magnesium space holder technique
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Porous Ti-6Al-4V alloys are widely used in the biomedical applications for hard tissue implantation due to their elastic moduli being close to that of bone. In this study, porous Ti-6Al-4V alloys were produced with a powder metallurgical process, space holder technique, where magnesium powders were utilized to generate porosity in the range of 51-65 vol%. The production of porous Ti-6Al-4V alloys was composed of three steps. Firstly, spherical Ti-6Al-4V powders with an average size of 55 mu m were mixed wit...
Knotless anchors offer better prevention of meniscal excursion than knotted anchors: An experimental study of the bovine knee
EREN, MEHMET BURTAÇ; Asci, Murat; Tönük, Ergin; BALTA, ORHAN; Kurnaz, Recep (2020-01-01)
Objective: Due to the biomechanical importance of the meniscal root ligament, several surgical techniques have been defined in order to treat meniscal root tear. Different application techniques have different levels of difficulty. We aimed to find a stronger and simpler repair technique. Methods: Sixteen bovine knee joints were prepared. The posterior root of the medial meniscus was dissected and repaired with one of two different techniques. The knees in group 1 ("knotted group") were repaired with the k...
Citation Formats
G. Bahçecioğlu, “Poly(L-Lactic acid) (PLLA)-based meniscus tissue engineering,” M.S. - Master of Science, Middle East Technical University, 2011.