title: Plasmonic ELISA for the detection of analytes at ultralow concentrations with the naked eye.
abstract: This protocol describes a signal-generation mechanism for the naked-eye detection of analytes at low concentrations with ELISA. The key step is to generate solutions of desired tonality by growing gold nanoparticles with a particular state of aggregation. This is accomplished by linking the growth of gold nanoparticles with the biocatalytic cycle of the enzyme label. The protocol adapts a conventional ELISA procedure with catalase-labeled antibodies. The enzyme consumes hydrogen peroxide, and then gold (III) ions are added to generate gold nanoparticles. The concentration of hydrogen peroxide dictates the state of aggregation of gold nanoparticles. This allows for the naked-eye detection of analytes by observing the generation of blue- or red-colored gold nanoparticle solutions. When coupled with conventional ELISA, this signal-generation procedure allows for the naked-eye detection of analytes within 1 h.
authors: Department of Materials, Imperial College London, London, UK. roberto.delarica@gmail.com
authors: Roberto
authors: R
authors: de la Rica
authors: Molly M
authors: MM
authors: Stevens
mesh_terms: D002374:Catalase / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006046:Gold / Q000032:analysis / Q000737:chemistry*; D016655:HIV Core Protein p24 / Q000032:analysis; D006861:Hydrogen Peroxide / Q000737:chemistry; D053768:Metal Nanoparticles / Q000032:analysis / Q000737:chemistry*; D017430:Prostate-Specific Antigen / Q000032:analysis; D019809:Streptavidin / Q000737:chemistry
chemical_list: D016655:HIV Core Protein p24; D006046:Gold; D019809:Streptavidin; D006861:Hydrogen Peroxide; D002374:Catalase; D017430:Prostate-Specific Antigen
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