Method and device for biospecific affinity reactions

Claim 1

In a method of performing analyses based upon biospecific reactions in heterogeneous systems, comprising the steps of (a) providing a self-supporting carrier matrix body capable of absorbing and retaining liquid and having a first receptor component immobilized to the pore surfaces thereof, (b) sampling a predetermined volume of a liquid having dissolved therein a second ligand component that is to be determined, (c) contacting said predetermined sample volume with the matrix bocy to be completely absorbed and retained thereby, (d) permitting said first and second components to react to form an immobilized complex, and (e) detecting, and optionally quantitating the formation of said immobilized complex in said matrix, (f) the improvement comprising optimizing the total reaction rate of said second component with said first component by providing said first receptor component covalently bonded to the pore surfaces of said matrix in a sufficient amount for said total reaction rate to be dependent on the diffusion of said second component in the liquid phase, and by minimizing the influence of said diffusion by selecting the pore dimensions of said matrix body so that the total diffusion process therein substantially corresponds to that of a matrix having cylindrical pores with a diameter of less than about 200 μm, but sufficiently large to permit easy passage of the reagents, to thereby make said total reaction rate substantially independent of said diffusion.