Determination of apparent thermodynamic parameters for adsorption of a midchain peptidyl residue onto a glass surface

✍ Scribed by Latour, Robert A. ;Trembley, Sharon D. ;Tian, Yuan ;Lickfield, Gary C. ;Wheeler, A. P.

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 219 KB
• Volume: 49
• Category: Article
• ISSN: 0021-9304
• DOI: 10.1002/(sici)1097-4636(200001)49:1<58::aid-jbm8>3.0.co;2-v

✦ Synopsis

Protein adsorption onto the surface of an implanted material is widely recognized as an important factor controlling the biological response. Although numerous studies have been conducted to investigate protein adsorption behavior, very little is actually understood regarding the specific molecular events involved in protein-surface adsorption processes. As a basic science approach to investigate protein-surface interactions, an experimental method is developed and applied to determine apparent thermodynamic parameters for the adsorption of a single midchain peptidyl residue onto a glass surface. This article presents the results of adsorption studies for four molecular weight ranges of poly-L-lysine onto glass microspheres in physiologic saline at four temperatures. Isotherm data plots are constructed and the apparent changes in enthalpy (⌬H°), entropy (⌬S°), and Gibbs' free energy (⌬G°) are calculated assuming a Langmuir-like model for adsorption. Estimates of apparent ⌬H°, ⌬S°, and ⌬G°for the adsorption of a single midchain lysine residue are determined from the initial slopes of the plots of the apparent thermodynamic parameters versus the degree of polymerization of the adsorbed poly-L-lysine. It is proposed that the generation of such molecular-level adsorption data is a necessary step toward the goal of understanding, predicting, and controlling proteinsurface interactions.