A 3D printed PCL/hydrogel construct with zone-specific biochemical composition mimicking that of the meniscus

Bahcecioglu, Gokhan
Hasırcı, Nesrin
Bilgen, Bahar
Hasırcı, Vasıf Nejat
Engineering the meniscus is challenging due to its bizonal structure; the tissue is cartilaginous at the inner portion and fibrous at the outer portion. Here, we constructed an artificial meniscus mimicking the biochemical organization of the native tissue by 3D printing a meniscus shaped PCL scaffold and then impregnating it with agarose (Ag) and gelatin methacrylate (GelMA) hydrogels in the inner and outer regions, respectively. After incubating the constructs loaded with porcine fibrochondrocytes for 8 weeks, we demonstrated that presence of Ag enhanced glycosaminoglycan (GAG) production by about 4 fold (p < 0.001), while GelMA enhanced collagen production by about 50 fold (p < 0.001). In order to mimic the physiological loading environment, meniscus shaped PCL/hydrogel constructs were dynamically stimulated at strain levels gradually increasing from the outer region (2% of initial thickness) towards the inner region (10%). Incorporation of hydrogels protected the cells from the mechanical damage caused by dynamic stress. Dynamic stimulation resulted in increased ratio of collagen type II (COL 2) in the Ag-impregnated inner region (from 50% to 60% of total collagen), and increased ratio of collagen type I (COL1) in the GelMA-impregnated outer region (from 60% to 70%). Wewere able to engineer a meniscus, which is cartilage-like at the inner portion and fibrocartilage-like at the outer portion. Our construct has a potential for use as a substitute for total meniscus replacement.


A double-porosity model for a fractured aquifer with non-Darcian flow in fractures
Altinors, Altay; Onder, Halil (Informa UK Limited, 2008-08-01)
Non-Darcian flow in a finite fractured confined aquifer is Studied. A stream bounds the aquifer at one side and all impervious Stratum at the other. The aquifer consists of fractures capable of transmitting water rapidly, and Porous blocks which mainly store water. Unsteady flow in the aquifer due to a Sudden rise in the stream level is analysed by the double-porosity conceptual model. Governing equations for the flow in fractures and blocks are developed using the continuity equation. The fluid velocity in...
A probabilistic model for the assessment of uncertainties in the shear strength of rock discontinuities
DUZGUN, HSB; Yücemen, Mehmet Semih; Karpuz, Celal (Elsevier BV, 2002-09-01)
Discontinuity shear strength plays a critical role in many problems encountered in rock engineering, especially in the design of rock slopes. Since its precise estimation is generally not possible, it is crucial that the errors and uncertainties associated with its estimate be quantified and reflected in the design procedure. In this study, the uncertainties underlying discontinuity shear strength are thoroughly examined and an uncertainty analysis model is developed for the estimation of in situ discontinu...
An Experimental Study of Cutting Performances of Worn Picks
Dogruoz, Cihan; Bolukbasi, Naci; Rostami, Jamal; Acar, Cemil (2016-01-01)
The best means to assess rock cuttability and efficiency of cutting process for using mechanical excavation is specific energy (SE), measured in full-scale rock cutting test. This is especially true for the application of roadheaders, often fitted with drag-type cutting tools. Radial picks or drag bits are changed during the operation as they reach a certain amount of wear and become blunt. In this study, full-scale cutting tests in different sedimentary rock types with bits having various degree of wear we...
An analytical study on minimum confinement in spiral columns
Özkaya, Cenan; Özcebe, Güney; Department of Civil Engineering (2005)
The minimum spiral ratio equation given in the codes is derived by equating the strength at the second peak to the strength at the first peak for spiral columns tested under uniaxial load. In this study, specimen behavior under combined bending and axial load was taken as basis while deriving proposed equations. Analyses were carried out by using a Moment-Curvature program. For normal strength concrete, one regression and one simplified equation giving minimum spiral ratio are proposed. Difference between t...
Anatomical meniscus construct with zone specific biochemical composition and structural organization
Bahcecioglu, G.; Bilgen, B.; Hasırcı, Nesrin; Hasırcı, Vasıf Nejat (2019-10-01)
A PCL/hydrogel construct that would mimic the structural organization, biochemistry and anatomy of meniscus was engineered. The compressive (380 +/- 40 kPa) and tensile modulus (18.2 +/- 0.9 MPa) of the PCL scaffolds were increased significantly when constructs were printed with a shifted design and circumferential strands mimicking the collagen organization in native tissue (p < 0.05). Presence of circumferentially aligned PCL strands also led to elongation and alignment of the human fibrochondrocytes. Gen...
Citation Formats
G. Bahcecioglu, N. Hasırcı, B. Bilgen, and V. N. Hasırcı, “A 3D printed PCL/hydrogel construct with zone-specific biochemical composition mimicking that of the meniscus,” BIOFABRICATION, pp. 0–0, 2019, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/29890.