Graft Copolymer-Templated Mesoporous TiO2 Films Micropatterned with Poly(ethylene glycol) Hydrogel: Novel Platform for Highly Sensitive Protein Microarrays

In this study; we describe the use of organized mesoporous titanium oxide (TiO2) films as three-dimensional templates for protein microarrays with enhanced protein loading capacity and detection sensitivity. Multilayered mesoporous TiO2 films with high porosity and good connectivity were synthesized using a graft copolymer consisting of a poly(vinyl chloride) (PVC) backbone and poly(oxyethylene methacrylate) (POEM) side chains as a structure-directing template. The average pore size and thickness of the TiO2 films were 50-70 nm and 1.5 mu m, respectively. Proteins were covalently immobilized onto mesoporous TiO2 film via 3-aminopropyltriethoxysilane (APTES), and protein loading onto TiO2 films was about four times greater than on planar glass substrates, which consequently improved the protein activity. Micropatterned mesoporous TiO2 substrates were prepared by fabricating poly(ethylene glycol) (PEG) hydrogel microstructures on TiO2 films using photolithography. Because of non-adhesiveness of PEG hydrogel to towards proteins, proteins were selectively immobilized onto surface-modified mesoporous TiO2 region, creating protein microarray. Specific binding assay between streptavidin/biotin and between PSA/anti-PSA demonstrated that the mesoporous TiO2-based protein microarrays yielded higher fluorescence signals and were more sensitive with lower detection limits than microarrays based on planar glass slides.