Nanoparticle sensor having a nanofibrous membrane scaffold

A method of forming a sensor for sensing an analyte, comprising:

• forming a sensing medium on a substrate, by:
• depositing a suspension of cellulose nanofibers in an aqueous medium onto the substrate;
• allowing the suspension of cellulose nanofibers to gel into a nanofibrous layer over the substrate;
• coating the cellulose nanofibers in the nanofibrous layer with a plurality of metallic nanoparticles, the plurality of metallic nanoparticles being derivatized to reversibly interact with the nanofibrous layer and an analyte, based on at least one of electronic charge, ligand coordination, hydrogen bonding, van der Waals force, polarity, hydrophilicity, and hydrophobicity;
• and
• forming at least one electrode, for sensing a change in a state of the sensing medium over time responsive to the analyte, and producing an electrical signal output corresponding to the change in the state,
• the sensing medium being responsive to a change in the analyte by a change in the electrical signal output.

A method of forming a sensor, comprising:

• forming a sensing medium by:
• casting a layer of organic nanofibers in an aqueous slurry on a substrate, under conditions which cause the organic nanofibers in the aqueous slurry to gel, the organic nanofibers having exposed groups capable of at least one of ionic bonding, hydrogen bonding, and van der Waals interaction;
• and
• decorating the organic nanofibers with a plurality of nanoparticles by depositing a solution containing insoluble conductive nanoparticles, derivatized with a ligand which at least one of ionically bonds, hydrogen bonds, and van der Waals bonds with the organic nanofibers, on the layer of the organic nanofibers, to link the nanoparticles with nanofibers within the layer of the organic nanofibers;
• forming at least one electrode configured to sense a state of the sensing medium, and to produce an electrical signal output corresponding to the state.