Surface modification of poly(dimethylsiloxane)-fabricated microfluidic chip by UV radiation

UV radiation was applied to modify the surface of poly (dimethylsiloxane) (PDMS)-fabricated microfluidic replica. After the surface of PDMS was irradiated by a 6 W low pressure mercury lamp, the adhesion between PDMS plates was significantly strengthened, and the PDMS plates were irreversibly sealed when the irradiated surfaces were brought into contact. Hydrophilic behavior of PDMS replica was improved due to the photochemical reaction induced by UV radiation, resulting in a significant increase in the electroosmotic flow of buffers filled in the microchannels of the chip. Compared with the reported procedures using oxygen plasma pretreatment, the present approach allows one to easily modify the surface of PDMS plates using very simple and cheap equipment available in analytical laboratory.