Monolithic Multicolor Total Internal Reflection (TIR)-Based Chip for Highly-Sensitive Multifluorescence Detection and Imaging

We present a multicolor total internal reflection (TIR)-based chip capable of generating up to four overlapping evanescent fields for highly-sensitive multifluorescence detection and imaging. The monolithic chip was fabricated using Si bulk micromachining and PDMS casting. Our proposed method integrates all miniaturized components, including prism, cylindrical microlenses, fiber stopper and alignment grooves, into one single PDMS chip; thus assembly is unnecessary, and misalignment is eliminated. The chip capabilities were demonstrated by detecting simultaneously two fluorescent dyes, namely tetramethylrhodamine (TMR) and fluorescein (FI), and then imaging a mixture of Nile-red (NR) and Dragon-green (DG) microbeads in two overlapping evanescent illumination modes. Such a device could be a key component in highly-sensitive multifluorescence molecular detection in mu-TAS.