Patent ID: 7214500

Claim:
A method for preparing a biosensor chip comprising two groups of polymers expressed by the following general formula (I) which are linked onto the sensor chip surface via the A-moiety present at one end of said polymers: general formula (I) A-(CH 2 ) p -L 1 -(CH 2 C 2 O) n -L 2 -X (I) in which A stands for HS— group, L 1 stands for a first linker or valence bond, L 2 stands for a second linker or valence bond, X stands for hydrogen, a functional group, protected functional group or ligand, p is an integer of 2–12, and n is an integer of, on the average, 10–10,000, in which one group of said polymers have an integer, n, as an average value, of 50–10,000 and the other group of said polymers have an integer, n, as an average value less than that of said one group by at least 10, which comprises, (A) a step of contacting an aqueous solution of said one group of polymers expressed by a general formula (Ia): HS—(CH 2 ) p -L 1 -(CH 2 CH 2 O) n -L 2 -X (Ia) in which L 1 , L 2 , X, p and n have the same significations to those as defined as to the general formula (I), with the sensor chip surface of a metal selected from the group consisting of gold, silver, copper and aluminum, under the conditions sufficient to link a prescribed amount of said polymer to said metallic surface, and thereafter washing away the unlinked polymer; (B) a step of subsequently contacting an aqueous solution of said other group of polymers of general formula (Ia) which have an integer, n, as an average value, less than that of said one group of polymers in step (A) by at least 10, with the sensor chip surface which has undergone the above step A, under the conditions sufficient to link said polymer to said surface, and thereafter washing away the unlinked polymer; and (C) repeating the above step (A), (B) or both steps (A) and (B) plural times to obtain said biosensor chip.