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Design and manufacture of a bioreactor to apply compressive and shear forces to hydrogel samples
This project focuses on designing and manufacturing a bioreactor to apply compressive and shearing forces to cell-embedded hydrogel samples under real-world mechanical conditions in a sterile environment.
Keywords: Hydrogel, cartilage, bioreactor, loading device, compression, shear, CAD, FEA, 3D printing, DLP, FDM, CNC milling, in vitro culture.
The current goal standard to test biocompatibility and matrix deposition of cells consists in culturing samples in an incubator for up to 63 days with physiological temperature, O2 and CO2. At the same time, tissues such as cartilage and bone develop differently based on the mechanical conditions at which they are subjected. This is a standard biological phenomenon in all human beings that allows the body to optimally distribute bone and cartilage material in the areas where higher stresses are applied. It has been shown that compressive forces applied periodically to in vitro samples can up-regulate proteoglycan synthesis and moderately improve collagen II production. In one of her recent works, Di Federico showed that uniaxial compression accompanied with shear stresses can better mimic real-word cartilage conditions showing an up-regulation of collagen II production in agarose hydrogels, the main component of cartilage.
The scope of this project is to design and build a bi-axial loading system capable of applying up to 20% compressive strain and up to 20% shear strain to samples as they are cultured in an incubator up to 63 days (schematic on the right). FEA analysis will be performed to measure the stress distribution on the samples during loading. The device should be programmable to apply different sinusoidal compressive and shear stresses over time in a humid environment at 37 degrees Celsius.
The current goal standard to test biocompatibility and matrix deposition of cells consists in culturing samples in an incubator for up to 63 days with physiological temperature, O2 and CO2. At the same time, tissues such as cartilage and bone develop differently based on the mechanical conditions at which they are subjected. This is a standard biological phenomenon in all human beings that allows the body to optimally distribute bone and cartilage material in the areas where higher stresses are applied. It has been shown that compressive forces applied periodically to in vitro samples can up-regulate proteoglycan synthesis and moderately improve collagen II production. In one of her recent works, Di Federico showed that uniaxial compression accompanied with shear stresses can better mimic real-word cartilage conditions showing an up-regulation of collagen II production in agarose hydrogels, the main component of cartilage.
The scope of this project is to design and build a bi-axial loading system capable of applying up to 20% compressive strain and up to 20% shear strain to samples as they are cultured in an incubator up to 63 days (schematic on the right). FEA analysis will be performed to measure the stress distribution on the samples during loading. The device should be programmable to apply different sinusoidal compressive and shear stresses over time in a humid environment at 37 degrees Celsius.
During this master thesis, the student will perform a short literature review to estimate the forces in play when compressing cartilage and bone samples as they develop over time. The student will be introduced to 3D CAD modeling software, FEA modeling software, 3D printing using FDM and DLP technologies and CNC milling. Previous knowledge or experience of any technique is considered a plus. The device will be finally tested by culturing samples for 21 days and comparing their development against samples cultured without any mechanical loading.
During this master thesis, the student will perform a short literature review to estimate the forces in play when compressing cartilage and bone samples as they develop over time. The student will be introduced to 3D CAD modeling software, FEA modeling software, 3D printing using FDM and DLP technologies and CNC milling. Previous knowledge or experience of any technique is considered a plus. The device will be finally tested by culturing samples for 21 days and comparing their development against samples cultured without any mechanical loading.
To apply please send a short motivation letter together with your CV to the above email. Do not hesitate to contact us for more information.
Responsible PhD student: Enrico Tosoratti at enrico.tosoratti@hest.ethz.ch
Head of the laboratory: Prof. Dr. Marcy Zenobi Wong at marcy.zenobi@hest.ethz.ch
To apply please send a short motivation letter together with your CV to the above email. Do not hesitate to contact us for more information.
Responsible PhD student: Enrico Tosoratti at enrico.tosoratti@hest.ethz.ch
Head of the laboratory: Prof. Dr. Marcy Zenobi Wong at marcy.zenobi@hest.ethz.ch