Abstract:

In this study we design new fabrication techniques and demonstrate the potential of using dense CO₂ for facilitating crucial steps in the fabrication of polymeric lab-on-a-chip microdevices by embedding biomolecules at temperatures well below the polymer’s glass transition temperature (T_g). These new techniques are environmentally friendly and done without the use of a clean room. Carbon dioxide at 40 °C and between 4.48 and 6.89 MPa was used to immobilize the biologically active molecule, β-galactosidase (β-gal), on the surface of polystyrene microchannels. To our knowledge, this is the first time dense CO₂ has been used to directly immobilize an enzyme in a microchannel. β-gal activity was maintained and shown via a fluorescent reaction product, after enzyme immobilization and microchannel capping by the designed fabrication steps at 40 °C and pressures up to 6.89 MPa.