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

AUTOR(ES)

Droz, E

RESUMO

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.

Documentos Relacionados

• Arrays of hemispheric surface projections on Chlamydia psittaci and Chlamydia trachomatis observed by scanning electron microscopy.
• Dictyostelium discoideum fruiting bodies observed by scanning electron microscopy.
• Chirality of DNA supercoiling assigned by scanning force microscopy.
• Large secretory structures at the cell surface imaged with scanning force microscopy.
• Subfibrillar structure of type I collagen observed by atomic force microscopy.