Manufacturing optimisation and assembly of biofilm flow cell

• Main Author: Cheng, Ze Wei.
• Other Authors: Christopher Shearwood
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Mechanical engineering::Prototyping
• Online Access: http://hdl.handle.net/10356/53552
• Institution: Nanyang Technological University

Biofilms are of great interest to researchers due to their wide ranging impact on society. This impact can be either positive or negative. In the medical sector biofilms are the main cause of infections. Examples of negative impact include infections cause by medical implants (including dentistry), catheters, infections of the bladder and prostate, hardening of the arteries, fouling of marine hulls and reverse osmosis membranes, etc. However, harnessing the power of bacteria can also have positive outcomes such as the deactivation of sludge in water treatment facilities, energy from bio-fuel cells, a healthy digestive system, brewing of alcohol, etc. Unlike normal cells, the developmental biology of bacteria and biofilms is controlled by external factor especially environmental gradients. Rather than trying to kill biofilms using anti-fouling agents or antibiotics it is better to study the relationship between the developmental biology and environmental gradients so that biofilm formation can be prevented or the resultant biofilms easily dispersed. A new tool has been developed to address this issue. This tool is a fluidic cell, designed so that a biofilm can be grown on a glass-cover slip and viewed using a high resolution confocal microscopy. By the reproducible control of the fluidic gradients, the biology of the bacteria can be controlled and studied in great detail. A novel planar flow cell prototype has been developed, and this project aims to manufacture the device using plastic injection moulding. As the initial design was imperfect, Design of Experiment (DOE) and Finite Element software were used to analyse the devices and the parameters used in injection moulding. Eventually, the device had to be thickened to address problems with defects such as trapped air and warpage. Also, several assembly methods were reviewed in this project, resulting in the selection of Ultrasonic bonding. As well as satisfying the requirements for a strong hermetic bond, the cost and environmental impact of the device was minimized.