Design and development of a biopolymer microfiber fabrication device

• Main Author: Yap, Yi-Liang.
• Other Authors: Chua Chee Kai
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Mechanical engineering::Prototyping; DRNTU::Engineering::Materials::Biomaterials
• Online Access: http://hdl.handle.net/10356/39438
• Institution: Nanyang Technological University

Tendon injury is common but so far, there has yet to be any satisfying treatment for it. One emerging approach is to reconstruct the tendon by Tendon Tissue Engineering (TTE). This is done by culturing cells on a biodegradable scaffold. Existing approach generally involves in vitro culture of cell before in vivo implantation of the cell-scaffold construct. However in vitro environment has been shown to be inferior to the in vivo environment, in terms of natural healing factors and biocompatibility issues. Hence, a novel approach is proposed to conduct TTE fully in vivo. In this report, a microfiber fabrication device is designed and developed to produce unfused biopolymer microfiber bundle. This end-product will be used as scaffold material in the in vivo cultivation approach research. As a scaffold material for tendon tissue, the scaffold has to be unfused so that it may move apart in wet environment to allow cell infiltration. Also, the microfiber cannot contain toxic additives that may harm the human body. In order to mimic the tendon tissue, the microfiber has to be within the range of 1 µm to 20 µm and the bundle to be around 500 µm. In order to do so, the device must be able to sustain a continuous production of fiber for at least 1 minute and have a production rate higher than 1 mg/min. Moreover, the device has to be economical to fabricate and easy to set up because it is meant for laboratory scale production of microfiber. It should also be relatively portable to allow increased mobility. Finally, the device should be able to produce a variety of end products. Heat drawing is the method used in producing the microfiber. Molten polymer within a holding cup with a tiny orifice below is drawn by a needle and stuck onto a spinning mandrel for collection. As the melt is pulled from the orifice, extensional flow causes the thinning in the melt diameter and the atmosphere cools the melt down into a fiber before it is collected on the mandrel. Preliminary test results show that the prototype is able to produce micro-scale fiber although it is 3 microns out of the accepted range. It is proposed that by decreasing diameter of the cup’s orifice, as well as optimizing melt temperature and mandrel rotation speed, microfiber diameter within acceptable range can be produced. Apart from that, the device is shown to fulfill the other criteria for usage in a laboratory scale microfiber production.