Modelling and Development of a Microfluidic Platform for Dielectrophoretic Separation of Polymeric Nanoparticles

• Autor(a) principal: Rebordão, Guilherme Santos
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/112989
• topic: Microfluidics; Particle separation; Dielectrophoresis; Photolithography; COMSOL Multiphysics; SU-8; Domínio/Área Científica::Engenharia e Tecnologia::Nanotecnologia

The interest surrounding particle separation techniques has increased significantly in the past years, due to its importance in chemical and biological analysis, diagnostics, and food processing, among other areas. Out of the vast array of ways that have been used to separate particles in microfluidics, electric field may be the most common means of separation, given its applicability and versatility. Dielectrophoresis (DEP) occurs in the presence of a non-uniform electric field, and in order to achieve such field, there are two main approaches: by creating an array of metal electrodes along the main channel or by utilizing an electrodeless design. This latter approach is based on creating constrictions on the channel while applying an electric field between the inlet(s) and outlet(s) of the channel. In this work, done in the Department of Materials and Production of the University of Aalborg, five different models were designed and fabricated on a single fused silica wafer via photolithography, with the ultimate purpose of continuously separating particles with diameters of 20 nm and 150 nm. A detailed overview of the designs and COMSOL simulations, as well as the fabrication techniques and processes can be found throughout the work. Successful particle separation was achieved in the simulations, at voltages as low as 35 V, with the use of separation channels with a maximum length of 3.1 mm. The fabrication stage of the work was focused on the development of a robust microfabrication process suitable for small, well-defined channels, and its alignment with metal electrodes. Two different fabrication approaches were presented and analysed.