AVS 53rd International Symposium
    Biomaterial Interfaces Friday Sessions
       Session BI-FrM

Paper BI-FrM4
Adsorption-Induced Changes in Protein Bioactivity Correlated with Adsorbed Protein Orientation and Conformation

Friday, November 17, 2006, 9:00 am, Room 2014

Session: Biomolecular Surface Characterization II
Presenter: K.P. Fears, Clemson University
Authors: K.P. Fears, Clemson University
R.A. Latour, Clemson University
Correspondent: Click to Email
It is well accepted that an irreversibly bound adsorbed protein layer forms on biomaterial surfaces very rapidly after they come in contact with bodily fluids. The structure and bioactivity of this adsorbed protein layer are recognized to be critical factors that influence subsequent cellular responses; however, little is known about the actual molecular mechanisms involved. The bioactivity of an adsorbed protein could be inhibited due to adsorption-induced conformational changes in the proteinâ?Ts structure or due to orientational effects that result from the active site being sterically blocked by the surface. A set of experimental methods have been developed using alkanethiol self-assembled monolayers (SAMs), with different surface chemistries, along with surface plasmon resonance (SPR) spectroscopy to measure the adsorption-induced changes in protein bioactivity using enzymes with well known molecular structures. The secondary structure of the adsorbed protein layers was determined using circular dichroism (CD) and compared to the native structure of the proteins. Molecular models of the proteins showing the location of hydrophobic and charged residues, as well as the active site residues, were analyzed along with the data collected on adsorbed protein bioactivity and secondary structure to identify the most likely cause for the measured changes in bioactivity as a function of surface chemistry.