AVS 50th International Symposium
    Biomaterial Interfaces Thursday Sessions
       Session BI+SS-ThA

Paper BI+SS-ThA4
MALDI MS of Proteins Separated on a Chemical Gradient Modified Open Channel Microchip

Thursday, November 6, 2003, 3:00 pm, Room 318/319

Session: Biodiagnostics
Presenter: X. Li, University of Texas at Arlington
Authors: G.R. Kinsel, University of Texas at Arlington
X. Li, University of Texas at Arlington
R.B. Timmons, University of Texas at Arlington
Correspondent: Click to Email
Efficient methods for protein separation and characterization are critical to the success of a wide array of biological and biomedical research activities. Current methods involve electrophoretic separation of proteins, followed by staining, excision, digestion and analysis of isolated proteins by Matrix-Assisted Laser Desorption / Ionization Mass Spectrometry (MALDI-MS). This approach is both time consuming and subject to significant protein loss resulting from the various manipulations of the sample. Research in our laboratory is directed at circumventing these limitations through the incorporation of the sample separation process directly on the surface of the MALDI-MS sample stage. In our approach substrates suitable for use as the MALDI sample stage are modified to incorporate open electrophoretic separation channels. Substrates that have been employed include PMMA chips, which are patterned using heat-imprinting methods, and silicon wafers, which are patterned using conventional plasma etching methods. A chemical gradient is developed along the separation channel by masking adjacent areas and sequentially depositing thin films on the channel via pulsed RF plasma polymerization of allyl alcohol at various duty cycles. Control mixtures of peptides having varying hydrophilicity are electrokinetically injected into the gradient chemically modified open channel, eletrophoretically separated and then analyzed by rastering the MALDI desorption laser across the channel while acquiring MALDI mass spectra. Successful results obtained to date, demonstrate the potential value of this approach for improving sensitivity and specificity in MALDI MS analysis.