Streptavidin-Functionalized Three-Dimensional Ordered Nanoporous Silica Film for Highly Efficient Chemiluminescent Immunosensing

A novel biofunctionalized three-dimensional ordered nanoporous SiO2 film is designed for construction of chemiluminescent analytical devices. The nanoporous SiO2 film is prepared with self-assembly of polystyrene spheres as a template and 5-nm SiO2 nanoparticles on a glass slide followed by a calcination process. Its functionalization with streptavidin is achieved by using 3-glycidoxypropyltrimethoxysilane as a linker. Based on the high-selectivity recognition of streptavidin to biotin-labeled antibody a novel immunosensor is further constructed for highly efficient chemiluminescent immunoassay. The surface morphologies and fabrication processes of both the biofunctionalized film and the immunosensor are characterized using scanning electron microscopy, atomic-force microscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The three-dimensional ordered nanopores have high capacity for loading of streptavidin and antibody and promote the mass transport of immunoreagents for immunoreaction, thus the resulting chemiluminescent immunosensor shows wide dynamic range for fast immunoassay, and good reproducibility and stability. Using carbohydrate antigen 125 (CA 125) as a model, the highly efficient chemiluminescent immunosensing shows a linear range of three orders of magnitude, from 0.5 to 400 U mL(-1). This work provides a biofunctionalized porous nanostructure for promising biosensing applications.