| Microfluidic devices for biochemical microarrays are fabricated and tested. They are designed and used for the purpose of label free protein assays within a Surface Plasmon Resonance (SPR) detection system. These microfluidic devices consist of microchannels and spotting regions, defined in PDMS, aligned to gold patterned SPR slides. Solution flow through the microchannel devices is achieved using vacuum. As solutions are flowed through and incubated in the microchannels, immobilization occurs at the gold sensing regions of the SPR slides. The dimensions of the gold sensing regions are optimized for coupling with the dimensions of the microchannel and the optical sensing system of the SPR instrument. The gold deposition is achieved in a thermal evaporator using a novel lithographically produced PDMS shadow mask. These masks can be used to produce metal deposited patterns in the 10-6 m range. Considerations for the design of the microchannel manifold included; ease of fabrication, assembly and use, minimization of the number of inlets and outlets, channel design to minimize possible air bubble trapping, ensuring no cross-spot contamination and maintaining equal resistance to flow between microchannels. Physisorption of human blood serum proteins; albumin, fibrinogen, IgA, IgM and IgG were investigated against functionalized C11 thiol thin films. Use of the microfludic spotting device as a flow cell is also demonstrated through in situ covalent protein immobilization and protein assay testing. Initial work is also presented in developing an IgE immunoassay utilizing SPR label free detection. |
