Surface modification of microfluidic chip and its application in protein enrichment

Aldehyde groups were produced on silica surface through silanisation using 3-Aminopropyltri-ethoxysilane and Terephthal-dicarboxaldehyde self-assembly. 125 nm ramification was formed on silica surface after modification process. Immunoglobulin G (IgG) was immobilized on silica surface through condensation reaction between an amine and an aldehyde. Activity of IgG was investigated through antigen-antibody reaction. A micro-fluidics chip with an elliptical micro-pillar array was fabricated. The inner surface area and contact opportunity of fluid increased than the chip without micro-pillar array. Human IgG was immobilized on the micro-pillar arrays through such a process. Then, fluoroisothiocyanate (FITC)-conjugated goat antibody to human IgG phosphate buffer solution (PBS) solution was introduced into the channel of the micro-fluidics chip. The results indicate that the fluorescence intensity increases up to 15 times after going through the micro-fluidics chip. Experiment show antibody can be attached on silica surface though this way and its activity is retentive. Protein can be enriched through such a surface modified micro-fluidics chip.