A study of the autofluorescence of parylene materials for µTAS applications
Parylene-C has been widely used as a biocompatible material for microfluidics and micro total analysis system (µTAS) 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 µTAS 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 µTAS applications with fluorescence detection.
Additional Information© 2010 The Royal Society of Chemistry. Received 27th November 2009, Accepted 19th March 2010. First published on the web 29th April 2010. The authors would like to thank Beckman Institute Laser Resource Center of Caltech for the spectrofluorimeter, and Dr John Bercaw's group of Caltech for their FT-IR Spectrometer. The author would like to thank Alec Durrell and Alex Miller for equipment training and experiment assistance. Also the authors would like to thank Kuang Shen from the Chemistry Department of Caltech for his helpful discussion and assistance. The funding is provided by NIH, under Award Number 4000072624.
Published - Lu2010p10804Lab_on_a_Chip.pdf