| AVS 55th International Symposium & Exhibition | |
| Biomaterial Interfaces | Tuesday Sessions |
| Session BI-TuP |
| Session: | Biomaterials Interfaces Poster Session with Focus on Cells and Proteins at Interfaces |
| Presenter: | E.S. Leibner, The Pennsylvania State University |
| Authors: | E.S. Leibner, The Pennsylvania State University N. Barnthip, The Pennsylvania State University W. Chen, The Pennsylvania State University C.R. Baumrucker, The Pennsylvania State University J.V. Badding, The Pennsylvania State University M.V. Pishko, Texas A&M University E.A. Vogler, The Pennsylvania State University |
| Correspondent: | Click to Email |
Analytical protocol greatly influences measurement of human-serum albumin (HSA) adsorption to commercial expanded polytetrafluororethylene (ePTFE) exhibiting superhydrophobic wetting properties (water contact angles in excess of 150°). Degassing of buffer solutions and evacuation of ePTFE adsorbent to remove trapped air immediately prior to contact with protein solutions are shown to be essential steps that assure reproducible measurement of HSA adsorption. Results obtained with ePTFE as a superhydrophobic test material suggest that vacuum degassing should be generally applied in the measurement of protein adsorption to any surface exhibiting superhydrophobicity. Solution depletion quantified using radiometry (I-125 labeled HSA) or electrophoresis (unlabeled HSA) yield different measures of HSA adsorption, with nearly seven-fold higher surface concentrations of unlabeled HSA measured by the electrophoresis method. This outcome is attributed to the influence of the radiolabel on HSA hydrophilicity which decreases radiolabeled-HSA affinity for a hydrophobic adsorbent in comparison to unlabeled HSA. These results indicate that radiometry underestimates the actual amount of protein adsorbed to a particular material. Removal of radiolabeled HSA adsorbed to ePTFE by 3X serial buffer rinses also shows that the remaining “bound fraction” was about seven-fold lower than the amount measured by radiometric depletion. This observation implies that measurement of protein bound after surface rinsing significantly underestimates the actual amount of protein concentrated by adsorption into the surface region of a protein-contacting material.