AVS 49th International Symposium
    Biomaterials Wednesday Sessions
       Session BI-WeP

Paper BI-WeP10
Temperature-Responsive Polymer Coatings by Plasma Polymerization and Applications for Protein and Cell Patterning

Wednesday, November 6, 2002, 11:00 am, Room Exhibit Hall B2

Session: Biointerfaces and Surfaces II
Presenter: X. Cheng, University of Washington
Authors: X. Cheng, University of Washington
Y. Wang, University of Washington
Y. Hanein, University of Washington
K. Bohringer, University of Washington
B.D. Ratner, University of Washington
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The thermo-responsive polymer, poly (N-isopropylacrylamide) (pNIPAM), is of great interest for research and industrial applications in separation, controlled release, tissue engineering, sensor technology, etc. In this study, RF-plasma deposition is used to create temperature responsive ppNIPAM (plasma polymerized NIPAM) coatings. Films with a good retention of the monomer side-chain functionality are produced using low power continuous plasma deposition. Protein adsorption on the coating is studied at below and above the lower critical solution temperature (31°C) using both 125I-proteins and SPR. Dramatic increases of fibrinogen, IgG and BSA adsorption (8 fold, 8 fold and 10 fold respectively) are demonstrated at 37°C on ppNIPAM films compared to the adsorption at room temperature. Proteins adsorbed at 37°C do not detach two hours after switching the incubation temperature to 23°C, in contrast to the reported reversible cell detachment from pNIPAM upon temperature drop. Antibodies adsorbed on ppNIPAM at 37°C remain functionally active, as demonstrated by SPR studies. The coating has been deposited on micro-heater arrays. The individual micro-heaters control the phase transition of the ppNIPAM directly on top of it. Spatially controlled protein adsorption on the array has been visualized through a fluorescent marker. Based on preferential adhesion of cells to certain proteins, cells can be patterned on the protein arrays and used for tissue engineering applications.