To provide a reagent with excellent stability under storage, which can detect a subject compound to be measured with higher specificity and sensitibity. Complexes of a compound represented by the general formula (I): ##STR1## (wherein R.sub.1 through R.sub.7 independently represent hydrogen atom, halogen atom, alkyl group, aryl group, aralkyl group, sulfonate group, amino group, styryl group, nitro group, hydroxyl group, carboxyl group, cyano group, or aryl azo group; R.sub.1 through R.sub.7 may or may not be bonded to each other to form a substituted or an unsubstituted condensed ring; R represents a divalent organic residue; and X.sub.1.sup..crclbar. represents an anion) and the like with immunoglobulin and the like are formed.
The invention provides a biologically active substance transfer sheet which can be formed with simple steps, a cell culture kit which comprises a cell culture plate and a biologically active substance transfer sheet, a producing method therefor, and a method for screening cell culture conditions with cells. The transfer sheet is prepared by providing biologically active substances having biological activity in plural areas on a sheet base, and biologically active substances are supplied from the sheet to culture regions provided on the plate.
