Patent ID: 7544504

Claim:
A non-invasive method for the detection of the presence or absence of a Helicobacter pylori antigen in a biological sample comprising: a) contacting a biological sample obtained from a patient suffering or suspected of suffering from H. pylori infection with a biosensor comprising (i) a carrier substrate which has a solid surface, (ii) antibodies against H. pylori , or antigen-binding fragments-thereof, and (iii) hydrophilic biomolecule-repellent molecules; wherein: the solid surface of the carrier substrate produces a surface plasmon resonance (SPR) signal; both the antibodies or antigen-binding fragments thereof and the hydrophilic biomolecule-repellent molecules comprise a functional group having affinity for the solid surface of the carrier substrate; both the antibodies or antigen-binding fragments thereof and the hydrophilic biomolecule-repellent molecules are covalently attached directly to the solid surface of the carrier substrate through the functional group having affinity for the solid surface of the carrier substrate, thereby forming a monolayer; both the antibodies or antigen-binding fragments thereof and the hydrophilic biomolecule-repellent molecules are self-assembled on the solid surface of the carrier substrate; and the antibodies or antigen binding fragments thereof are attached to the solid surface of the carrier substrate at the same time as, or prior to, attachment of the hydrophilic biomolecule-repellent molecules to the solid surface of the carrier substrate; and b) detecting the signal resulting from the formation of an antibody-antigen-complex; wherein the hydrophilic biomolecule-repellent molecules are neutral hydrophilic monomers or polymers selected from the group consisting of polyacrylamide, poly-N,N-dimethylacrylamide, and N-[tris(hydroxymethyl)methyl]acrylamide.