Naked-eye detection as a universal approach to lower the limit of detection of enzyme-linked immunoassays

O'Connor, Erin F. and Paterson, Sureyya and De La Rica, Roberto (2016) Naked-eye detection as a universal approach to lower the limit of detection of enzyme-linked immunoassays. Analytical and Bioanalytical Chemistry, 408 (13). pp. 3389-3393. ISSN 1618-2642

[img]
Preview
Text (OConnor-Paterson-de-la-Rica-ABC2016-Naked-eye-detection-as-a-universal-approach-to-lower-the-limit)
OConnor_Paterson_de_la_Rica_ABC2016_Naked_eye_detection_as_a_universal_approach_to_lower_the_limit.pdf
Accepted Author Manuscript

Download (1MB)| Preview

    Abstract

    Colorimetric biosensors for the detection of analytes with the naked eye are required in environmental monitoring, point-of-care diagnostics, and analyses in resources constrained settings, where detection instruments may not be available. However instrument-based detection methods are usually more adequate for detecting small variations in the signal compared to naked-eye detection schemes, and consequently the limit of detection of the latter is usually higher than the former. Here we demonstrate that the limit of detection of colorimetric enzyme-linked immunoassays can be decreased several orders of magnitude when using naked-eye detection instead of a spectrophotometer for detecting the signal. The key step to lower the limit of detection is adding a small volume of chromogenic substrate during the signal generation step. This generates highly colored solutions that can be easily visualized with the naked eye and recorded with the camera of a mobile phone. The proposed method does not require expensive equipment or complex protocols to enhance the signal, and therefore it is a universal approach to lower the limit of detection of colorimetric enzyme-linked immunoassays.