Engineering surfaces to control microfluidic flow in lab-on-a-chip devices

Blanco-Gomez, Gerald (2009) Engineering surfaces to control microfluidic flow in lab-on-a-chip devices. PhD thesis, University of Glasgow.

Abstract

Laboratory-on-a-chip technologies have received growing interests in last 20 years as a method to miniaturise, parallelise, and optimise chemical reactions and biological detections normally carried out at the macro-scale. As a generic tool, microfluidics can be presented as the science of regulation, controlling the transport of matter, delivering reagents for reactions occurring on-chip. This highly interdisciplinary research field exploits the increase in the resolution of methods of detection whilst reducing the necessary amount of material to react or be detected. The domain of microfluidic is situated between the nanofluidic’s and the millifluidic’s ones, and concerns devices whose critical dimension lies between 50 nm and 200 μm. The work in this thesis realised the development of a device engineered to facilitate the implementation of a microfluidic calibration platform which will, in future, have applications in chip structures such as the laboratory-ina-pill (LIAP). To introduce pump and valve, it is presented the fabrication of a controllable microfluidic valve coupled with an electrochemical pump which have been designed to deliver stored reagent to an integrated biosensing system. The on-chip valve can build up a flow back pressure of several kPa, efficient to store solutions. Novel fabricated material reported here, show reversible and tuneable superhydrophobic surfaces using a combination of epoxy-based resist SU-8 and spin-on silicon elastomer. The biocompatibility of this new material was also tested showing promising properties applied in tissue engineering. Microfluidic actuators are usually based on the initiation of a transport mechanism based on convection within the system (using a mechanical structure, phase change, and the generation of external forces). Many researches were conducted upon using large voltage supplies and or significant power consumption. The electrolysis of water (involving phase change) was chosen as the source of forced convection within the microfluidic channel. Flow rates in such miniaturised devices range between nL.min-1 and μL.min-1 depending on the applied voltage for electrolysis.In detail, the need for the insertion of liquids of interest has previously involved the use of external tubing impinging on the overall size of the device. Our approach enabled reductions in the size of the device as a compact geometry the integration of a number of fluidic components on the same chip. A system was produced that can potentially operate on low power with small size batteries.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Due to confidentiality restrictions the full text of this thesis cannot be made available online.
• Keywords: microfluidic, wettability, micropump, microvalve, lab-on-a-chip, biosensor, self-assembly
• Subjects: T Technology > TK Electrical engineering. Electronics Nuclear engineering
• Colleges/Schools: College of Science and Engineering > School of Engineering
• Supervisor's Name: Cooper, Prof. Jonathan M.
• Date of Award: 2009
• Depositing User: Mr. Gerald Blanco-Gomez
• Unique ID: glathesis:2009-1194
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 23 Oct 2009
• Last Modified: 04 Mar 2024 16:52
• Thesis DOI: 10.5525/gla.thesis.1194
• URI: https://theses.gla.ac.uk/id/eprint/1194