(129b) Surface Plasmon Resonance Protein Binding Studies On Reactive Vapor Deposition Coatings

Authors: 
Ross, A. M., University of Michigan
Zhang, D., Washington University in St. Louis
Chang, S. L., University of Michigan, Ann Arbor
Lahann, J., University of Michigan
Xiaopei, D., University of Michigan


Biomolecular interactions with synthetic surfaces are important in diverse biomedical fields including medical device implants, microfluidic sensors, marine fouling, and tissue engineering. In the past, chemical vapor deposition (CVD) polymerization has been used to fabricate thin polymer films with robust mechanical and physical properties. Functional groups on CVD coatings serve as anchors for the immobilization of biomolecules and thus the affinity of surfaces for various proteins, antibodies, or antigens can be modulated. As a result, CVD films are well suited for use as protein/antigen-antibody sensors or in controlling the cellular microenvironment for microfluidic cell culture. However, for many of applications, it would be beneficial to understand kinetics, or time based interactions, of CVD surfaces with biomolecules as well as the extent of these interactions. Therefore a cascade of surface modifications on CVD coatings was explored using a microfluidic technique known as surface plasmon resonance (SPR). CVD films are well suited for SPR studies because in addition to their biofunctionality, they are easily attached to gold which serves as a substrate for SPR assays. In this work, we exploit protein-surface interactions in order to demonstrate the feasibility of thin film CVD surfaces, in particular a functionalized [2.2]paracyclophanes (PPXCOC2F5), as a spatially-resolved sensing array for SPR studies. Additional analysis techniques include Fourier transform infrared spectroscopy (FTIR), electrical impedance spectroscopy (EIS), imaging ellipsometry, and fluorescence microscopy. FTIR confirmed the presence of the thin film and EIS indicated that CVD films were pin hole free. Results from imaging ellipsometry verified that films of varying thickness were created which then allowed the impact of film thickness on protein sensing to be assessed. SPR and fluorescence microscopy findings demonstrated that CVD films acted as antigen-antibody sensors and that SPR sensitivity is impacted by increasing film thickness. Potential applications of this sensing scheme include preclinical screening of drugs/pharmaceuticals.