A dual-color Total Internal Reflection (TIR)-based chip for simultaneous detection of two fluorophores

We report a novel, dual-color total internal reflection (TIR)-based chip which can generate two overlapping evanescent fields for simultaneous detection of two fluorophores. The chip was monolithically fabricated using Si bulk micromachining and PDMS casting. Our proposed method integrated all miniaturized components, including two cylindrical microlenses, one prism, two fiber alignment grooves and two fiber stoppers, into one monolithic PDMS chip; thus assembly is unnecessary, and misalignment is avoided. We first demonstrated the capabilities of the chip by detecting simultaneously two fluorescent dyes, namely Tetramethylrhodamine (TMR) and Fluorescein. We then employed the chip to image mixture of Nile-red (NR) and Dragon Green (DG) fluorescent beads. Our miniaturized, integrated device could be an alternative to the conventional dual-color Total Internal Reflection Fluorescent Microscopy (dual-color TIRFM) systems. It could also be a useful component of a micro-Total Analysis System (mu-TAS) for highly-sensitive dual-color fluorescent detection.