AVS 53rd International Symposium
    Biomaterial Interfaces Friday Sessions
       Session BI-FrM

Paper BI-FrM5
SIMS Detection of Peptides on Alkanethiol Self-Assembled Monolayers

Friday, November 17, 2006, 9:20 am, Room 2014

Session: Biomolecular Surface Characterization II
Presenter: Z. Zhu, Pacific Northwest National Laboratory
Authors: Z. Zhu, Pacific Northwest National Laboratory
O. Hadjar, Pacific Northwest National Laboratory
P. Wang, Pacific Northwest National Laboratory
J. Laskin, Pacific Northwest National Laboratory
Correspondent: Click to Email
Alkanethiol self-assembled monolayers (SAM) on Au substrate provide a very ordered and controllable surface which is friendly to bio-molecules. Numerous protein or DNA molecules have been immobilized on alkanethiol SAMs to fabricate bio-active surfaces which can be used for bio-analysis or some other applications. A number of techniques, such as fluorescence, X-ray photoelectron spectroscopy (XPS), reflection IR, surface plasmon resonance, have been applied to detect these bio-active molecules immobilized on alkanethiol SAM surfaces. During the last several years, secondary ion mass spectrometry (SIMS) detection of bio-active molecules has been of great interest, and a number of efforts have been reported. Although several papers have addressed on SIMS detection of bio-active molecules on alkanethiol SAM surfaces, the detection limit of this technique is not clear. Since static SIMS is a very surface-specific technique, sample preparation plays a very important role in such research. In this work, the electrospray technique was used to prepare samples due to its effectiveness, easy control and simple operation. Sub-monolayer of three peptides (Bradykinin, MW=1060.5; Gramicidin S, MW=1141.6; Substance P, MW=1347.7) were prepared on three alkanethiol SAMs (-S(CH2)11CH3, -S(CH2)10CO2H, -S(CH2)2(CF2)9CF3) and detection limits were tested. 15 keV Ga+ ions were used as the primary ion source. It has been found that the detection limit of peptide molecules can be as low as 0.0001 monolayer or even lower. Our results show that SIMS is a very promising technique to characterize low-mass protein molecules on alkanethiol SAM surfaces.