The Method Of Micro-nanofluidic Chip Fabrication And Its Application In Enrichment

In recent years, with the development of fabricating technologies of microfluidic chip, fabricating technologies of nanofluidic chip or micro-nanofluidic Chip has also been rapidly developed. Micro-nanofluidic chip is used in the research such as ion or molecular analysis, separation and enrichment, so it has broad research space and application prospect. With an increasing smaller size of Nanochannel flow, nanofluidic chip has some special properties such as surface electrical charge, the electrical double layer, increased viscosity and decreased electroosmotic flow. These special properties make micro-nanofluidic chip play an important role in biochemical analysis. This thesis focuses on the fabrication methods of micro-nanofluidic chip and has fabricated glass and PDMS micro-nanofluidic chip. This thesis uses micro-nanofluidic chip to do the efficient enrichment experiments of ions and protein at last.In this thesis, glass materials are used to fabricate micro-nanofluidic chip, because the glass material has excellent optical properties and electrical properties, and other good characteristics like all to the same anisotropic etching and high precision manufacture. Adding to the structural features of micro-nanofluidic chip, this thesis uses photolithography and wet etching process to fabricate microchannel and nanochannel chips respectively. Afer the channels are formed, the upper plate and the bottom plate can be assembled together by alignment, preconnection and thermal bonding sequently. At last, the bottom plate and the upper one are irreversibly linked together with thermal bonding.As PDMS material is a cheap and relatively simple production process with the feature of short production cycle. PDMS material has great advantages in microfluidic chip fabrication. The author fabricates a SU-8 mold of the PDMS microfluidic chip, and then employs the casting process to make a microfluidic chip. With the help of cooperating party, the PDMS micro-nanofluidic chip is finally fabricated where the bottom layer and the upper layer are both PDMS microfluidic chips while the middle layer is a mesoporous membrane. This is a micro-nanofluidic chip with sandwich structure.Finally, this thesis makes preliminary study of the characteristics of the micro-nanofluidic chip, surface charge, electrical double layer and the size effect. The ionic concentration of the solution is several times higher than before. The author also does a lot of experiments to explore the method of using BSA/FITC solution as a protein enrichment solution and achieved good results.