Miniature fluidic devices for nanoparticle synthesis with biomedical applications

• Main Author: Hong, Liying
• Other Authors: Yong Ken Tye
• Format: Theses and Dissertations
• Language: English
• Published: 2017
• Subjects: DRNTU::Engineering::Nanotechnology; DRNTU::Engineering::Electrical and electronic engineering
• Online Access: http://hdl.handle.net/10356/69472
• Institution: Nanyang Technological University

Nanoparticles exhibit very distinct characteristics from their bulk counterparts, therefore there is great interest in studying the properties of these nanomaterials for various applications such as biophotonics, photovoltaics, and nanomedicine. Miniature devices not only provide the conveniences of small physical footprints and system portability, but also serve as excellent platforms to give us insight into the molecular interactions at reduced length and volume scales, requiring less amount of sample and hastening the sample processing time. Therefore, the union of these two concepts is the motivation behind this thesis as miniaturization of reaction vessels can provide better control over the reaction conditions, enabling higher reproducibility and tighter size distributions. As a result, nanocrystals with superior qualities like high monodispersity and narrow emission linewidths can be easily reproduced with less chemical wastage. In this thesis, synthesis of several nanoparticles using millimetre dimensioned channels in miniaturized devices are presented. Firstly, plasmonic nanoparticles were synthesized for photodynamic therapy. By varying the flow rate and molar ratios of the precursors, nanoparticles with different shapes, sizes, and crystal structures were fabricated. Secondly, monodispersed semiconductor nanoparticles with interesting optical characteristics were also produced. Modifying the relative ratio of the reactants and their injection rate yielded particles with different morphologies. These nanoparticles were then used for cell imaging. Lastly, preliminary studies on a dye encapsulated micelle constructed using a chip based millifluidic device were carried out. The goal is to extend this approach to increase the drug loading efficiency of multimodal fluorescent particles. The polymer was used for drug delivery can encapsulate chemotherapy drugs to enable controlled drug release in the cellular environment. Adjusting the relative flow rate of the injected streams, different mixing regimes could be achieved, affecting considerations such as the sizes of the particles. These factors are critical and have a profound impact on the drug loading efficiency. Therefore, the miniaturization of nanoparticle synthesis methods provides windows of opportunity to integrate such devices for real-time spectroscopy and analysis of these nanoparticles and subsequent incorporation with other fluidic technologies such as biosensing and flow cytometry.