Organic Silicone Sol-gel Polymer as a Non-covalent Carrier of Receptor Proteins for Label-free Optical Biosensor Application
ACS applied materials & interfaces | 25 Dec 2012
J Ren, L Wang, X Han, J Cheng, H Lv, J Wang, X Jian, M Zhao and L Jia
Optical biosensing techniques have become of key importance for label-free monitoring of biomolecular interactions in the current proteomics era. Together with an increasing emphasis on high-throughput applications in functional proteomics and drug discovery, there has been demand for facile and generally applicable methods for the immobilization of a wide range of receptor proteins. Here, we developed a polymer platform for microring resonator biosensors, which allowed the immobilization of receptor proteins on the surface of waveguide directly without any additional modification. A sol-gel process based on a mixture of three precursors was employed to prepare a liquid hybrid polysiloxane, which was photopatternable for the photocuring process and UV imprint. Waveguide films were patterned on silicon substrates and characterized by atomic force microscopy for roughness, and protein adsorption. The results showed that the spin-coating polymer surface was smooth (Rms = 0.658 nm), and exhibits a moderate hydrophobicity with the water contact angle of 97 degree. Such a hydrophobic extent could provide a necessary binding strength for stable immobilization of proteins on the material surface in various sensing conditions. Biological activity of the immobilized Staphylococcal protein A and its corresponding biosensing performance were demonstrated by its specific recognition of human Immunoglobulin G. This study showed the potential of preparing dense, homogeneous, highly specific, and highly stable biosensing surfaces by immobilizing receptor proteins on polymer-based optical devices through the direct physical adsorption method. We expect that such polymer waveguide could be of special interest in developing low-cost and robust optical biosensing platform for multidimensional arrays.
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