AVS 52nd International Symposium
    Biomaterial Interfaces Thursday Sessions
       Session BI1-ThM

Paper BI1-ThM1
Long Lifetime Polymer Microfluidic Devices for HPLC-MS Applications

Thursday, November 3, 2005, 8:20 am, Room 311

Session: BioMEMS and Microfluidics
Presenter: K.L. Seaward, Agilent Laboratories
Authors: K.L. Seaward, Agilent Laboratories
D.L. Ritchey, Agilent Laboratories
K.P. Killeen, Agilent Laboratories
H. Yin, Agilent Laboratories
R.A. Brennen, Agilent Laboratories
Correspondent: Click to Email
Polymer microfluidic devices have been developed for High Performance Liquid Chromatography with integrated nano-electrospray tips for interfacing to Mass Spectrometry. HPLC-MS is regarded as a preferred analytical technique for protein identification in very small (nanoliter) volumes of sample and has been used, for example, to determine protein content in blood. Commercially available microfluidic devices consist of separate parts for liquid chromatography and electrospray functionality connected with fittings. This leads to difficulties in use, compromised performance, and complicated fabrication. The devices described in this presentation are made in a biocompatible polyimide and contain sample enrichment and liquid chromatography columns plus electrospray tips. Their size is approximately 2.5cm x 6cm with 200-400 micron thickness in a multi-layered structure made by direct laser writing of patterns followed by vacuum lamination. Laser cutting of electrospray tips and incorporation of metal traces in the layer structure provide electrospray functionality. A rotary valve interface between high-pressure fluids delivered by a nanoflow pump and the microfluidic device itself provides efficient fluid switching between various ports on the device. Gas-phase plasma processes, similar to those found in microelectronic device manufacturing, are used in the fabrication process. These are critical to ensure long lifetime performance of the devices, resulting in repeatable high-pressure performance of the column structures and stable electrospray behavior. In combination with mass spectrometry, state-of-the-art attomole level detection of protein digests has been demonstrated using these microfluidic devices. The device fabrication will be outlined and recent applications to proteomics will be shown.