title: Plasmonic ELISA for the ultrasensitive detection of disease biomarkers with the naked eye.
abstract: In resource-constrained countries, affordable methodologies for the detection of disease biomarkers at ultralow concentrations can potentially improve the standard of living. However, current strategies for ultrasensitive detection often require sophisticated instruments that may not be available in laboratories with fewer resources. Here, we circumvent this problem by introducing a signal generation mechanism for biosensing that enables the detection of a few molecules of analyte with the naked eye. The enzyme label of an enzyme-linked immunosorbent assay (ELISA) controls the growth of gold nanoparticles and generates coloured solutions with distinct tonality when the analyte is present. Prostate specific antigen (PSA) and HIV-1 capsid antigen p24 were detected in whole serum at the ultralow concentration of 1 × 10(-18) g ml(-1). p24 was also detected with the naked eye in the sera of HIV-infected patients showing viral loads undetectable by a gold standard nucleic acid-based test.
authors.affiliation: Department of Materials, Department of Bioengineering and Institute for Biomedical Engineering, Imperial College London, Exhibition Road, London, UK. roberto.delarica@gmail.com
authors.forename: Roberto
authors.initials: R
authors.lastname: de la Rica
authors.forename: Molly M
authors.initials: MM
authors.lastname: Stevens
mesh_terms: D000911:Antibodies, Monoclonal / Q000097:blood; D015415:Biomarkers / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006046:Gold / Q000737:chemistry; D016655:HIV Core Protein p24 / Q000097:blood; D015658:HIV Infections / Q000175:diagnosis; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry; D017430:Prostate-Specific Antigen / Q000097:blood; D012680:Sensitivity and Specificity; D019562:Viral Load
chemical_list: D000911:Antibodies, Monoclonal; D015415:Biomarkers; D016655:HIV Core Protein p24; D006046:Gold; D017430:Prostate-Specific Antigen