AVS 51st International Symposium
    Biomaterial Interfaces Friday Sessions
       Session BI+MN-FrM

Paper BI+MN-FrM10
Ultrasensitive MALDI MS Analysis of Peptides Separated in an RF Plasma Polymer Modified Microfluidic Device

Friday, November 19, 2004, 11:20 am, Room 210D

Session: Bio-MEMS and Microfluidics
Presenter: G.R. Kinsel, University of Texas at Arlington
Authors: G.R. Kinsel, University of Texas at Arlington
X. Li, University of Texas at Arlington
Correspondent: Click to Email
Rapid, information rich analysis of complex biological samples, such as the proteome of a given cellular system, represents a significant challenge for modern bioanalytical devices. A prototype open-channel microfluidic device under development in laboratory integrates an array of technologies available and/or developed in our laboratory to achieve efficient separation and ultrasensitive detection the components of peptide/protein mixtures. Specifically, separation of peptide mixtures is achieved through electroosmotic flow of the sample through 100 micron open-channels imprinted into a PMMA wafer. Modulation of the separation characteristics is achieved by either using the channels as formed or following coating of the channels by pulsed RF plasma polymerization of thin films having various chemical properties. Changes in peptide retention characteristics have been observed to correlate with changes in the column coating chemistry. Separation of simple mixtures can be achieved in minutes using this device. Following separation of the peptides, MALDI mass spectra of the isolated compounds is achieved by rastering the desorption / ionization laser down the open channel. This approach clearly allows the unambiguous assignment of the peptide molecular weight. In addition, because of the confinement of the sample to extremely small volumes, and the consequent high surface concentrations, extremely low limits of detection have been obtained for the separated peptides e.g. an LOD of 1.6 attomole of the peptide casomorphin has been observed. The coupling of this microfluidic device with MALDI mass spectrometry clearly holds enormous promise for substantially lowering the limits of detection and the requisite analysis time, while providing maximum information content for components in complex peptide / protein mixtures.