STM imaging of molecules: factors affecting their reliable imaging

Nawaz, Zeesha; Cataldi, Tommaso R. I.; Knall, J.; Somekh, R.; Pethica, J. B.

doi:10.1016/0039-6028(92)90495-r

Cited by 37 publications

(11 citation statements)

References 48 publications

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“…A number of factors which influence how well the STM can image a particular molecule on a given surface have been discussed in detail in several recent publications. − A key factor is the contribution of the adsorbate electronic structure to the STM image. If the STM image is dominated by the adsorbate electronic states, the molecular image can be more readily interpreted than if the STM image is dominated by the electronic structure of the substrate with a small modification induced by the adsorbed species.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, STM imaging of adsorbed molecules has been successful when the adsorbate contribution to the wave function is >10%, while imaging of the internal structure of adsorbed molecules has been most successful for strongly chemisorbed molecules for which the adsorbate contribution to the wave function is ∼30−50% . Characteristics of the substrate, such as flatness and cleanliness, can also affect how easily adsorbed molecular structures can be distinguished from substrate structures …”

Section: Introductionmentioning

confidence: 99%

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Scanning Tunneling Microscopy Imaging of Small Adsorbed Molecules on Metal Surfaces in an Ultrahigh Vacuum Environment

Chiang

1997

Chem. Rev.

134

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Scanning Tunneling Microscopy Imaging of Small Adsorbed Molecules on Metal Surfaces in an Ultrahigh Vacuum Environment

Chiang

1997

Chem. Rev.

134

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“…Second, individual molecules have been imaged. This has been much more difficult, because often the molecules do not form stable interactions with the surface and can be displaced or damaged by the tip during scanning (Nawaz et al, 1992). In spite of this, since the pioneering observations of isolated viruses (Baro et al, 1985) many images of isolated molecules have been published, especially of nucleic acids (Arscott and Bloomfield, 1990;Thundat et al, 1992aThundat et al, , 1992b.…”

Section: Introductionmentioning

confidence: 99%

“…In the field of SPM imaging of biomolecules, most of the effort to date has been to optimize the scan parameters in order to reduce the damage done to the molecule (Engel, 1991;Nawaz et al, 1992). However, the central problem which has arisen is the reproducibility of the sample preparation.…”

Section: Introductionmentioning

confidence: 99%

Preparation of isolated biomolecules for SFM observations: T4 bacteriophage as a test sample

Droz¹,

Taborelli²,

Wells³

et al. 1993

Biophysical Journal

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The T4 bacteriophage has been used to investigate protocols for the preparation of samples for scanning force microscopy in air, in order to obtaining reproducible images. The resolution of images and the distribution of bacteriophages on the substrate depends on the buffer type, its concentration, the surface treatment of substrate, and the method of deposition. The best imaging conditions for the phages require dilution in a volatile buffer at low ionic strength and adsorption onto hydrophilic surfaces. When imaging with the scanning force microscopy the quality of the images is influenced by the vertical and lateral forces applied on the sample and by the tip geometry.

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“…Aggregates of several molecules are visible aligned along graphite steps or cut by the scanning probe, as indiated by the horizontal white stripes. Most of scanning probe microscopy studies of isolated biomolecules report such difficulties in imagig because of motion of the molecules on the surface caused by the interaction of the scanning tp with the samWle (Nawaz et al, 1992).…”

Section: Modificatio Of Hopg Surface By Glow Dishargementioning

confidence: 99%

Influence of surface and protein modification on immunoglobulin G adsorption observed by scanning force microscopy

Droz

Taborelli

Descouts

et al. 1994

Biophysical Journal

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Scanning force microscopy has been used successfully to produce images of individual protein molecules. However, one of the problems with this approach has been the high mobility of the proteins caused by the interaction between the sample and the scanning tip. To stabilize the proteins we have modified the adsorption properties of immunoglobulin G on graphite and mica surfaces. We have used two approaches: first, we applied glow discharge treatment to the surface to increase the hydrophilicity, favoring adhesion of hydrophilic protein molecules; second, we used the arginine modifying reagent phenylglyoxal to increase the protein hydrophobicity and thus enhance its adherence to hydrophobic surfaces. We used scanning force microscopy to show that the glow discharge treatment favors a more homogeneous distribution and stronger adherence of the protein molecules to the graphite surface. Chemical modification of the immunoglobulin caused increased aggregation of the proteins on the surface but did not improve the adherence to graphite. On mica, clusters of modified immunoglobulins were also observed and their adsorption was reduced. These results underline the importance of the surface hydrophobicity and charge in controlling the distribution of proteins on the surface.

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STM imaging of molecules: factors affecting their reliable imaging

Cited by 37 publications

References 48 publications

Scanning Tunneling Microscopy Imaging of Small Adsorbed Molecules on Metal Surfaces in an Ultrahigh Vacuum Environment

Scanning Tunneling Microscopy Imaging of Small Adsorbed Molecules on Metal Surfaces in an Ultrahigh Vacuum Environment

Preparation of isolated biomolecules for SFM observations: T4 bacteriophage as a test sample

Influence of surface and protein modification on immunoglobulin G adsorption observed by scanning force microscopy

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