title: A study of the autofluorescence of parylene materials for microTAS applications.
abstract: Parylene-C has been widely used as a biocompatible material for microfluidics and micro total analysis system (microTAS) applications in recent decades. However, its autofluorescence can be a major obstacle for parylene-C based devices used in applications requiring sensitive fluorescence detection. In this paper, Parylene-C was compared with other commonly used polymer and plastic materials in microTAS devices for their autofluorescence. We also report here an in-depth study of the behaviors and mechanisms of the autofluorescence of parylene-C, as well as several other commercialized members in the parylene family, including parylene-D, parylene-N and parylene-HT, using epifluorescence microscopy, fluorimeter and infrared spectroscopy. Strong autofluorescence was induced in parylene-C during short-wavelength excitation (i.e. UV excitation). Variation of autofluorescence intensity of parylene-C film was found to be related to both dehydrogenation and photo-oxidation. Moreover, the influence of microfabrication process on parylene-C autofluorescence was also evaluated. Parylene-HT, which exhibits low initial autofluorescence, decreasing autofluorescence behavior under UV excitation and higher UV stability, can be a promising alternative for microTAS applications with fluorescence detection.
authors.affiliation: Caltech Micromachining Laboratory, California Institute of Technology, MC 136-93, Pasadena, CA 91125, USA. lubo@mems.caltech.edu
authors.forename: Bo
authors.initials: B
authors.lastname: Lu
authors.forename: Siyang
authors.initials: S
authors.lastname: Zheng
authors.forename: Brandon Quoc
authors.initials: BQ
authors.lastname: Quach
authors.forename: Yu-Chong
authors.initials: YC
authors.lastname: Tai
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D008422:Materials Testing; D011108:Polymers / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D014992:Xylenes / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D011108:Polymers; D014992:Xylenes; C011055:parylene