Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

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.

Original publication




Journal article


Nat Protoc

Publication Date





1759 - 1764


Catalase, Enzyme-Linked Immunosorbent Assay, Gold, HIV Core Protein p24, Hydrogen Peroxide, Metal Nanoparticles, Prostate-Specific Antigen, Streptavidin