(501b) Ultra-Low Fouling and Antibody Functionalization Properties of Zwitterionic Carboxybetaine Polymer Films for Biosensing Applications

Recent advancements in biosensing technologies have enabled detection limits down to unprecedented sensitivities. However, a frequent disconnect arises between theoretical biosensor capabilities and the actual assay performance in real-life applications. The primary reason for this difference is due to the necessity of biosensing devices to both prevent the background noise associated with non-specific protein adsorption but also to enable the efficient immobilization of molecular recognition elements (i.e. typically antibodies) which is necessary for high sensitivity and selectivity. Zwitterionic carboxybetaine polymers (pCB) have been shown to be ultra-low fouling to undiluted human plasma and serum as well as the ability to maintain these properties following antibody functionalization. In order to improve the control over pCB film “quality”, several surface-initiated polymerization methods (i.e. atom transfer radical polymerization (ATRP) and photo-polymerization) with different antibody immobilization environments (i.e. for activation, protein attachment, and deactivation) were compared using a surface plasmon resonance (SPR) biosensor. The adjustment of pCB film parameters (thickness and packing density) enabled the combined relationship between non-fouling and functionalization to be determined. Finally, the subsequent affect on the bioactivity of an antibody functionalized sensor surface was also characterized. The result of this work provides a fundamental understanding between polymer surface morphology and its subsequent affect on the performance characteristics of biomaterials for biosensing devices.