Diagnostic chips, and biochemical reaction chips using solid phase carriers such as protein microarrays are very useful in the field of research and development and the clinical field. For example, in terms of a protein microarray or the like, a protein solution is brought into contact with a glass substrate to immobilize the protein on the substrate, and using the physiological activity of the immobilized protein, diagnosis or analysis is carried out. In this case, it is required that the protein can be immobilized at a high density and that the substance to be reacted with the immobilized protein not adsorb nonspecifically to the carrier.
To eliminate such non-specific adsorption, for example, in Proteomics, (2003) Vol. 3, pp. 254-264, a method wherein a protein is directly adsorbed and immobilized via a polylysine coating layer or an amino group layer and a method wherein a protein is immobilized by covalent bonding via an active ester layer formed by a multistep reaction are described.
Further, in Japanese Patent Application Laid-Open (JP-A) No. 2005-201901, a method is described wherein a substrate is directly carboxylated using a particular silane coupling agent and thereby activated to allow a protein to be covalently bound to the substrate. In cases where a silane coupling agent such as the one disclosed in JP-A 2005-201901 is used, in general, after coating a substrate with the silane coupling agent, the coating is solidified by a baking treatment at a temperature of not less than 100° C. to form a three dimensional network structure.
In such a method, although it is possible to immobilize a protein stably at a relatively high density, the density at which the protein is immobilized is not sufficient, and non-specific adsorption of the substrate to be reacted with the immobilized protein increases.
Further, in order to increase the amount of immobilization of a physically active ligand such as a protein, a solid phase carrier having a porous structure such as a non-woven fabric structure of fibers or a particle-packed structure is used.
For example, in JP 6-148190 A, a biochemical assay is carried out by allowing an acid anhydride to be covalently bound to a porous membrane. Further, in JP 8-506902 A, a biochemical assay is carried out by immobilizing an acid anhydride-containing polymer and a protein on a porous solid phase including glass-fiber paper. Further, in WO 2006/058237, an acid anhydride-containing polymer and a protein are immobilized, and when a biochemical assay is carried out, a blocking agent is used, thereby suppressing non-specific adsorption.    [Patent Document 1] JP-A 2005-201901    [Patent Document 2] JP-A 6-148190    [Patent Document 3] JP-A 8-506902    [Patent Document 4] WO 2006/058237    [Non-patent Document 1] Proteomics, (2003) Vol. 3, pp. 254-264