DNA Separation and Fluorescence Monitoring by Integrated Waveguides in an Optofluidic Chip

We report on the monolithic integration of optical waveguides and microfluidics in a fused-silica lab-on-a-chip. Labeled biomolecules such as double-stranded DNA are flown and separated in the microfluidic channel by capillary electrophoresis and their fluorescent labels are excited by a continuous-wave laser beam through femtosecondlaser-written integrated waveguides. In this context, desirable features such as high spatial resolution (~12 μm), and a low limit of detection (~ 6 nano-molar) have been experimentally demonstrated. The proof of concept is being extended to real-world diagnostic samples for on-chip diagnosis of genetic diseases, e.g. breast cancer.