Gold nanoparticles for naked-eye DNA detection: smart designs for sensitive assays

Abstract

Methods allowing colorimetric (instrument-free) detection of biomarkers at clinically relevant concentrations are highly desirable for point-of-care diagnostics. Gold nanoparticles (AuNPs) can fulfill such a scope in several ways. This review describes different schemes for AuNPs-based colorimetric detection of nucleic acid biomarkers, with a particular focus on factors, sometimes overlooked, which can help in the design of sensitive assays. These include AuNPs multivalency, ligand density on the surface of functionalized particles, and proper combination of AuNPs and enzymes, these latter being used for both signal amplification and PCR-free target amplification.