Biosensor device and method

Claim 1

A biosensor apparatus for detecting a binding event between a ligand and ligand-binding receptor, comprising a working electrode having (i) a conductive detection surface, (ii) formed on said conductive detection surface, a monolayer composed of hydrocarbon chains anchored at their proximal ends to said conductive detection surface, said chains being sufficiently close-packed and ordered to form an effective barrier to electron flow across the monolayer mediated by a redox ion species in an aqueous solution, when such a solution is placed in contact with the monolayer, and (iii) such ligand attached to the distal ends of a portion of said chains, such that binding of a ligand-binding receptor to ligand perturbs the monolayer sufficiently to measurably increase electron flow across the monolayer mediated by such redox ion species, a chamber for containing such an aqueous solution of redox species in contact with said monolayer, means for introducing receptor into said chamber, and circuit means for measuring ion-mediated electron flow across said monolayer, in response to binding events occurring between said receptor and ligand, said circuit means including a counter electrode positioned in said chamber to contact such aqueous solution, when the latter is placed in said chamber, wherein binding of receptor to the ligand on the working electrode is effective to perturb said monolayer, and thereby increase the flow of redox carriers in the solution across said monolayer, producing a detectable change in current flow between said working electrode n said counter electrode.