Nano/micro particle based microfluidic droplet manipulation and application

Abstract

Droplet microfluidics is a rapid developing research area, which has great promising application in lab-on-a-chip, point-of-care diagnostic and et al. In this thesis, micro/nano particles are introduced into droplet microfluidic chips for droplet generation, manipulation and application. They could be categorized in three types: magnetic nano particles(Fe3O4, Ni carbonyl iron), conductive micro/nano particles (Ag micro platelets and Carbon Black) and dielectric particles (giant electrorheological nano particles). Mono-dispersed magnetic micro spheres are prepared and their deformation under magnetic field is calibrated. Magnetically responded membrane is fabricated from magnetic elastomer CI-PDMS. Optimized ratio of CI/PDMS is found to be 2, and high efficiency micromixer is achieved by integrated the magnetic membrane into PDMS microfluidic chip. Then, structured AgPDMS pattern is integrated in microfluidic droplet detection chip as parallel electrodes and on-chip conducting wires. Connected with external detection circuit and Labview software, droplets could be detected and sorting according to their capacitance difference. Furthermore, GER fluids are injected into microfluidic channels, with the help of conducting component, 'smart' droplet generation and manipulation, as well as a universal droplet logic gate microfluidic chip is achieved, which shows the possibility of droplet communication and automatically control. Droplets could be coded, guided and stored, different logic functions could be conducted in one chip while varying the combination of applied voltages. What‘s more, droplet microfludic is also used in cell encapsulation for single cell manipulation (e.g. electroporation) to demonstrated application of droplet microfluidics. Some improvement in PDMS chip fabrication is presented for simplifying the fabrication of integrated multi-function microfluidic chips. All of these researches reveal the advantages of adoption of mircro/nano particles into droplet microfluidics: more control methods, more functionality and more automatically.

Date of Award	2011
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology