AVS 45th International Symposium
    Biomaterial Interfaces Group Monday Sessions
       Session BI-MoP

Paper BI-MoP3
In Situ AFM Study of Myoglobin Monolayers on Bare and Modified Graphite

Monday, November 2, 1998, 5:30 pm, Room Hall A

Session: Biomaterial Interfaces Poster Session
Presenter: S. Boussaad, Florida International University
Authors: M.J. Giz, IQSC/University of Sao Paulo, Brazil
S. Boussaad, Florida International University
N.J. Tao, Florida International University
Correspondent: Click to Email
We have examined with the atomic force microscopy (AFM) technique the structure of myoglobin (Mb) monolayers on graphite. This protein adsorbs weakly and slowly on bare graphite. The formation of a Mb monolayer can take up to 80 minutes. Furthermore, the molecules of Mb form a rod like assemblies randomly distributed on the surface of graphite. The length and the width of a single rod are 50 and 8 nm, respectively. The value of the width is similar to the dimension of a single protein. However, on graphite modified with a monolayer of Didodecyldimethylammonium bromide (DDAB) or Lauric acid (LA), the Mb is well ordered. The AFM images show that the protein preserves the rod-like assembly. In the case of DDAB, the Mb rods are aligned and almost parallel to each other, whereas on LA the rods are arranged into a V-type structure. In addition, the rods formed on modified graphite (70-80 nm) are much longer then their counter part on bare graphite. The Mb rods can be viewed as chains of 5-10 molecules and their formation can be attributed to an interaction between the proteins.