AVS 46th International Symposium
    Biomaterial Interfaces Group Tuesday Sessions
       Session BI-TuM

Paper BI-TuM6
Probing Immobilized Protein Peptide Architectures

Tuesday, October 26, 1999, 10:00 am, Room 613/614

Session: Protein Solid-Surface Interactions II
Presenter: S.J.B. Tendler, University of Nottingham, U.K.
Authors: S.J.B. Tendler, University of Nottingham, U.K.
M.M. Stevens, University of Nottingham, U.K.
W.C. Chan, University of Nottingham, U.K.
M.C. Davies, University of Nottingham, U.K.
C.J. Roberts, University of Nottingham, U.K.
P.M. Williams, University of Nottingham, U.K.
S. Allen, University of Nottingham, U.K.
Correspondent: Click to Email
The ability to control the assembly of molecular architecture at the nanometre scale is an important research goal. Complex molecular assemblies can be designed and constructed to have applications in several bio-analytical fields, for example, as key components in devices such as biosensors and affinity-based chromatographic supports. We have demonstrated the creation of a higher order molecular assembly which consists of a bis-biotinylated peptidic spacer between two streptavidin molecules. This molecular architecture exploits the strong affinity between streptavidin and biotin to promote self-assembly. Surface plasmon resonance has enabled us to monitor the construction of the multilayer in real time. Atomic force microscopy has been utilized to measure adhesion forces between biotinylated bovine serum albumin functionalized probes and the surface at each stage of the multilayer assembly. This facilitated the determination of surface functionality and associated mechanical properties at each of these stages. An increase in the elasticity of the system was observed once the multilayer was created. It is postulated that unraveling of an alpha-helical component in the conformation of the peptide before rupture of the streptavidin-biotin link may contribute to the increase in molecular elasticity of the multilayer. We have also demonstrated through a trifluoroethanol titration monitored by circular dichroism that variations in the solvent can affect the secondary structure of the peptide linker and hence its mechanical properties. These observations have wide implications for protein immobilization in terms of the precise control of distances of active layers, steric surface barriers, underlying surface forces and hence biological functionality.