Smart glass slide for microarrays

A method for detecting a biomolecule analyte in a biological sample, the method comprising:

• a) providing a biosensor comprising a multisite array of test sites in which the conditions for interacting with a biomolecule analyte can be varied independently, the biosensor having a device comprising a glass or plastic substrate supporting one or more electrodes and a biomolecular interface layer having immobilized pH sensitive Fluorescent Protein and one or more immobilized probes thereon, and at each test site having an aqueous solution comprising a dilute phosphate buffer and an electrochemically active agent;
• b) at each test site electrochemically reacting the electrochemically active agent in an aqueous solution to produce H+ ion or OH− ions, thereby modulating and controlling the pH at each test site;
• c) adding a biological sample to each test site;
• and
• d) detecting the biomolecule analyte in each test site,
• wherein the amounts of electrochemically active agent and the electrochemical reaction are varied between test sites in a subset array of test sites in order to obtain sets of test sites in which the pH or ionic concentration near electrode surfaces in the test sites varies, and wherein the pH at each test site is determined by the fluorescence intensity of the pH sensitive Fluorescent Protein.