Abstract
Tissue engineering is an interdisciplinary research that aims to repair and regenerate tissues and organs by transplanting artificial tissues fabricated outside the human body. To construct these tissues, one common approach is to harvest stem cells from the bone marrow of the patient and then culture these cells on a biomaterial as the scaffold to facilitate tissue development. However, many of the proposed scaffolds exhibit relatively simple intrinsic designs with limited control of cell distribution throughout the scaffold. In the thesis, novel scaffolds are designed for automatically seeding of biological cells via dielectrophoresis (DEP) for tissue engineering. This thesis is performed in the following three perspectives.First, a novel scaffold structure constituting multiple layers of bio-compatible materials is proposed to incorporate the technique of dielectrophoresis to manipulate and pattern biological cells in the three-dimensional (3D) domain. Different processing parameters are examined in order to determine their influence on the quality and viability of the 3D cellular patterns. Experimental results show that the designed scaffold and its automated dielectrophoresis-based patterning mechanism can be used to construct artificial tissues for tissue engineering applications.
Second, scaffold with honeycomb-like pores is designed to mimic the geometry of native bone tissue for the development of tissue regeneration. Cells on the scaffold are automatically patterned into multiple layers of honeycomb patterns. Three different types of mammalian cells are considered and different factors affecting the formation of the honeycomb patterns are identified by experimentation. Viability tests are conducted to examine the biocompatibility of the material and the cell death associated with the DEP mechanism.
Third, a new method to integrate active cell seeding mechanism via dielectrophoresis on 3D printed scaffolds is proposed. This scaffold adopted a concentric-ring design that is similar to native bone tissues. The scaffold can be fabricated with a commercial 3D printer. Polylactic Acid (PLA) is selected as the material for the printer and the fabricated scaffold is coated with gold to enhance the conductivity for DEP manipulation. Simulation study based on COMSOL software confirms that non-uniform electric fields can be successfully generated under a voltage input. The properties of the 3D-printed scaffold are characterized through a series of experiments.
In summary, this study has well demonstrated that the proposed scaffolds and their automated dielectrophoresis-based patterning mechanism can be well utilized to construct artificial tissues for tissue engineering applications. The multi-layer scaffold structure incorporates dielectrophoresis for manipulating cells in 3D patterns automatically. The development of the honeycomb-like scaffold enhances cell seeding for the development of high quality artificial bone tissues. The new type of 3D-printed scaffold offers a new and rapid way for fabricating engineered scaffolds that can arrange cells into different patterns. This thesis will help to promote the applications of dielectrophoresis mechanism in the development of artificial tissues.
| Date of Award | 21 Jun 2017 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Dong SUN (Supervisor) |