Method of functionalization of a gate electrode of a field-effect transistor sensor

1 . A method of functionalization of a gate electrode comprising the steps of:

forming a layer of biological recognition elements on a surface of said gate electrode, wherein said layer of biological recognition elements include a self- assembled structure of one or more specific-binding-pair-forming substances, the self- assembled structure including a biological self assembled structure of one or more specific-binding-pair-forming substances,

treating the layer of biological recognition elements with a solution containing a blocking agent to fill vacancies and prevent nonspecific binding in the self-assembled structure, wherein said blocking agent is a Bovine Serum Albumine solution,

wherein said one or more specific-binding-pair-forming substance immobilized in said layer of biological recognition elements are packed at a density between 0.1×10 4 μm −2 and 10×10 4 μm −2 ;

wherein the layer of biological recognition elements includes a biological self- assembled structure (B SAM) including said one or more specific-binding-pair-forming substance and a chemical self-assembled structure (C SAM) whereon said biological self-assembled structure is grafted,

wherein each of said chemical self-assembled structure (C SAM) and biological self-assembled structure (B SAM) is a self-assembled monolayer (SAM) structure,

wherein the chemical self-assembled monolayer (C SAM) is added to the gate electrode by means of a precursor consisting of a layer of alkanethiols terminating with carboxylic functionalities,

wherein said treating the layer of biological recognition elements (SAM) with a solution containing a blocking agent to fill vacancies and prevent nonspecific binding in the self-assembled structure (SAM) further comprises saturation of unreacted activated carboxy groups of said chemical self-assembled monolayer (C SAM) by means of concentrated solutions of amines for a time long enough to allow the reaction with all the activated carboxylic groups.

2 . The method of claim 1 , wherein said one or more specific-binding-pair-forming substances include one or more of the following:

one or more antibodies,

anti-human Immunoglobulin (anti-hIG) antibodies,

anti-human Immunoglobulin G (anti-IgG) antibodies,

anti-human Immunoglobulin M (anti-IgM) antibodies,

specific-binding-pair-forming substances for dopamine, chiral odors, DNA, PNA, human glycoprotein, inflammatory cytokines, C-reactive proteins.

3 . The method of claim 1 , wherein said step of treating the layer of biological recognition elements includes immerging the layer of biological recognition elements in the Bovine Serum Albumine solution in Phosphate Buffered Saline solution for a residence time comprised between 30 minutes and 2 hours, and at a temperature range of 22 to 26° C.

4 . The method according to claim 1 , wherein the gate electrode is further reacted in a 50 mM to 250 mM, 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide and 50 mM to 250 mM, N-Hydroxysuccinimide aqueous solution, for a residence time of 1 to 3 hours, and at a temperature of 22° C. to 26° C.

5 . The method according to claim 1 , wherein the biological self assembled monolayer is a self assembled monolayer of anti-human Immunoglobulin G treated with ethanolamine 1M in a Phosphate Buffered Saline solution for one hour at 25° C.

6 . The method according to claim 1 , wherein said biological self-assembled monolayer structure includes one or more proteins as specific-binding-pair-forming substances, wherein said one or more proteins are modified so to exhibit functional groupsreactive with the surface of the gate electrode.

7 . The method of claim 1 , wherein the density is between 1×10 4 μm −2 and 2×10 4 μm −2 .

8 . The method of claim 1 , wherein the Bovine Serum Albumine solution comprises 0.1 mg ml-1 and the Phosphate Buffered Saline solution comprises 10 mM.

9 . The method of claim 1 , wherein the blocking agent is a 0.1 mg ml-1 BSA solution in Phosphate Buffered Saline (PBS) 10 mM.