Site-Selective Molecular Adsorption at Nanometer-ScaleMeV-Atomic-Ion-Induced Surface Defects
✍ Scribed by Arjan P. Quist; Åsa Petersson; Curt T. Reimann; Anna A. Bergman; D.D.N.Barlo Daya; Anders Hallén; Jan Carlsson; Sven O. Oscarsson; Bo U.R. Sundqvist
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- English
- Weight
- 255 KB
- Volume
- 189
- Category
- Article
- ISSN
- 0021-9797
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✦ Synopsis
in a scanned, wide-area irradiation chamber (11) deployed on the Uppsala EN tandem van de Graaff accelerator. 127 I ions with kinetic energy 55 or The adsorption of Escherichia coli beta-galactosidase (bGal) 78.2 MeV impinged on the mica surfaces at a grazing angle of 79Њ with onto mica surfaces that had been irradiated with fast atomic ions respect to the surface normal. The applied fluence was roughly 3 ions/mm 2 . was studied with both ambient and liquid cell tapping mode scan-Certain samples were irradiated at normal incidence to a fluence of 2400 ning force microscopy (TM-SFM). The single-ion-impacts reions/mm 2 . sulted in hillock-like defects on the mica surfaces. Both with ambient and liquid cell TM-SFM, we observed an enhancement by a Ambient and Liquid Cell TM-SFM large factor for the preferential adsorption of bGal to surface defects, as compared to adsorption on the surrounding flat mica Samples were probed with tapping mode SFM (TM-SFM) (12, 13) basal plane. ᭧ 1997 Academic Press (Digital Instruments, Santa Barbara) using etched silicon probes with a nominal radius of curvature of 5-10 nm and oscillation resonance frequency Key Words: scanning force microscopy; SFM; tapping mode; of around 300 kHz for ambient experiments. For liquid cell (14, 15, 16) protein adsorption; preferential adsorption; ion-induced defects; experiments oxide-sharpened silicon nitride probes with a nominal radius spatially selective adsorption. of curvature of 5-40 nm and oscillation resonance frequency 50-100 kHz were used. Those probes sometimes have a double tip shape. Changing the field of view in liquid cell TM-SFM resulted in large lateral drift, thus