Pe. Mazeran et al., UNDER BUFFER SFM OBSERVATION OF IMMUNOSPECIES ADSORBED ON A CYANO GRAFTED SILICON SUBSTRATE1, Ultramicroscopy, 60(1), 1995, pp. 33-40
Scanning force microscopy (SFM) in contact mode and in liquid medium h
as been employed to study immunospecies layers adsorbed on a silicon w
afer. The silicon wafer has been grafted with a cyanosilane monolayer
in order to create a surface with strong adhesive properties which pre
vent proteins being swept by the scan of the SFM tip. The force curves
reveal that the adhesive force has been increased by a factor six wit
hout roughness modification (<1 nm). After the incubation of the surfa
ce in a monoclonal antibody (mouse anti-human alpha-fetoprotein IgG) s
olution, SFM surface images suggest an homogeneous layer composed by e
llipsoidal objects (40-60 nm in diameter, 6-13 nm in height), The subs
trate was moreover incubated in an antigenic solution (human alpha-fet
oprotein): SFM images reveal that proteins have been added onto the an
tibody layer.