Optical waveguide sensor for detecting radioactive isotopes and method of fabricating the same

An optical waveguide sensor for detecting ions containing radioactive isotopes in aqueous solution, wherein the optical wave guide sensor is fabricated by the steps of:

• treating a substrate surface by cleaning the substrate surface with one or more solvents for enabling coating of the treated surface with a crosslinking agent, the substrate being selected from a group comprising a silica or a silicon substrate;
• coating the treated substrate surface with the crosslinking agent selected from a group comprising carboxylic acid functional group containing organic molecules for forming a crosslinked substrate surface;
• coating the crosslinked substrate surface with a scintillating agent for forming a substrate surface containing scintillating agent;
• and
• coating the substrate surface containing scintillating agent with a ligand capable of reacting with a radioactive isotope in an aqueous solution for forming a functionalized substrate surface, thereby forming the optical waveguide sensor comprising a layer of the ligand and the scintillating agent,
• characterized in that,
• the coating of the treated substrate surface with the crosslinking agent is performed using a tin catalyst;
• the scintillating agent is selected from a group comprising a fluorescent crosslinker complex selected from a group comprising a hydroxyl functional group containing organic molecules complexed with ions selected from a group comprising Europium ions, Eu3+, nickel ions, Ni2+, or copper ions, Cu2+;
• and
• the ligand is selected from a group comprising carboxylic acid functional group containing organic molecules or an amine functional group ligand, wherein the selection of the ligand varies depending on the type of substrate surface and the types of ions containing radioactive isotopes to be detected,
• wherein the optical waveguide sensor is configured to be interactable with a light wave passing through the optical waveguide sensor from an input and an aqueous solution for determining concentration of the ions containing radioactive isotope in the aqueous solution,
• whereby,
• upon adsorption of the ions containing the radioactive isotope from the aqueous solution on the surface of the optical waveguide sensor, the molecules of the scintillating agent fluoresce in response to the ionizing radiation from the radioactive isotope of varying measurable intensity, and
• triggers a measurable change in material optical refractive index of the ligand of the functionalized substrate surface, which change corresponds to the absorption kinetics and radioactivity of the ions and its radioactive isotope.

An optical waveguide sensor for detecting ions containing radioactive isotopes in aqueous solution comprising:

• a substrate surface having a uniform thin layer of crosslinking agent, scintillating agent and ligand coupled thereto for forming a functionalized substrate surface, the substrate being selected from a group comprising a silica or a silicon substrate;
• characterized in that,
• the substrate surface is coated with the crosslinking agent selected from a group comprising carboxylic acid functional group containing organic molecules;
• the substrate surface is coated with the scintillating agent comprising a fluorescent crosslinker complex containing di- or poly alcohol molecules complexed with ions selected from a group comprising Europium ions, Eu3+, nickel ions, Ni2+, or copper ions, Cu2+;
• the substrate surface coated with the scintillating agent is coupled with the ligand via esterification, wherein the ligand is selected from a group comprising carboxylic acid functional group containing organic molecules or an amine functional group, whereby the selection of the ligand varies depending on the type of substrate surface and the type of ions containing radioactive isotopes to be detected, and
• wherein the optical waveguide sensor is configured to be interactable with a light wave from an input of the optical waveguide sensor and an aqueous solution in contact with the functionalized substrate surface for determining concentration of ions containing radioactive isotopes in the aqueous solution,
• whereby
• the ions containing radioactive isotopes in the aqueous solution are adsorbed by the functionalized substrate surface, causing the molecules of the scintillating agent to fluoresce upon receiving ionizing radiation from the radioactive isotope, and
• changing the material optical refractive index of the functionalized substrate surface, wherein the change of the material optical refractive index and fluorescence correspond to the concentration of the ions and its radioactive isotope.