Microfluidic devices hold much promise for small liquid volumes control due to their ability to manipulate small liquid volume from micorlitre to picolitre and easily parallelize and integrate with other analysis devices which can offer a number of practical applications in biotechnology, chemical synthesis and analytical chemistry....[ Read more ]

Microfluidic devices hold much promise for small liquid volumes control due to their ability to manipulate small liquid volume from micorlitre to picolitre and easily parallelize and integrate with other analysis devices which can offer a number of practical applications in biotechnology, chemical synthesis and analytical chemistry.

In this thesis, we started from using valve controlled microfluidic devices to control small liquid volume for temporal and spatial gradients generation and picoliter droplets delivery which can be applied in biological study and environmental toxicology. Using our valve controlled microfluidics, concentration oscillations and gradients were demonstrated to be controlled and predictable which would benefit researcher in probing cell physiology study in dynamically changing environment. Meanwhile, picoliter droplets delivery was achieved in an inexpensive and compact way. The method can be facile for operation and integration with other complicated devices.

New microfluidic systems for small liquid volume analysis were developed in the second part. We fabricated a capillary array microfluidics(CAE) coupled with microwell array to perform high-throughput electrophoresis in multiple capillaries simultaneously in terms of taking advantages of both microwell array technique and CAE. We also developed a membrane sandwiched microfluidic device for continuously access to droplets contents which could broaden the applications of microfluidic droplets.

In the last part, microfibers and microparticles were generated by manipulating liquid with mcirofluidic device. Convenient microfluidic strategies with a simple and minimal-requirement design were described for generation of uniformly-sized alginate gel fibers, droplets and mirobeads. Various functional materials (colloidal particles, bacteria and nanoparticles) have been encapsulated into the gel fibers. We believe that this technique will find applications in biomedical therapeutics, tissue engineering and microfluidics. In addition, Janus particles and microbeads array were formed in a convenient and facial way. Those kinds of particles can be utilized in various applications, such as electronic display and diagnosis.