Platinum-Decorated Gold Nanoparticles with Dual Functionalities for Ultrasensitive Colorimetric in Vitro Diagnostics

Abstract

Au nanoparticles (AuNPs) as signal reporters have been utilized in colorimetric in vitro diagnostics (IVDs) for decades. Nevertheless, it remains a grand challenge to substantially enhance the detection sensitivity of AuNP-based IVDs as confined by the inherent plasmonics of AuNPs. In this work, we circumvent this confinement by developing unique dual-functional AuNPs that were engineered by coating conventional AuNPs with ultrathin Pt skins of sub-10 atomic layers (i.e., Au@Pt NPs). The Au@Pt NPs retain the plasmonic activity of initial AuNPs while possessing ultrahigh catalytic activity enabled by Pt skins. Such dual functionalities, plasmonics and catalysis, offer two different detection alternatives: one produced just by the color from plasmonics (low-sensitivity mode) and the second more sensitive color catalyzed from chromogenic substrates (high-sensitivity mode), achieving an "on-demand" tuning of the detection performance. Using lateral flow assay as a model IVD platform and conventional AuNPs as a benchmark, we demonstrate that the Au@Pt NPs could enhance detection sensitivity by 2 orders of magnitude.

Plasmonic molecular assays: Recent advances and applications for mobile health

“…Xia et al used dualfunctional Au NP-Pt core-shell nanoparticles (Au@Pt NPs) as LFA labels which produced more sensitive color change catalyzed by the Pt layers. The Au@Pt NP imbedded LFA assay showed greatly enhanced detection sensitivity by 2 orders of magnitude compared to conventional Au NP probes [187]. Although LFA is currently still considered a simple yes/no diagnostic test, commercialization of above demonstrated ultrasensitive plasmonic nanoprobes in LFA is currently on the way.…”

Noble‐Metal Nanostructures as Highly Efficient Peroxidase Mimics

“…In particular, the reaction pathway of oxidation of peroxidase substrates by peroxides on metal surfaces ( e. g ., the adsorption and desorption of key species in the reaction) is still not fully understood. It has been reported that the adsorption energies between substrate ( e.g ., H 2 O 2 ) and metals and d‐band center of metals may be valuable parameters to predict the enzymatic activities of noble‐metal nanostructures . Future theoretical simulations may offer more insights into the catalytic reaction.…”

“…More recently, we have investigated the impact of Pt shell on the peroxidase‐like activity of Au@Pt n L core@shell nanospheres ( n L: n atomic layers of Pt) . As shown by Figure a, the Au@Pt n L nanospheres were synthesized by growing Pt on the surface of Au nanospheres as the seeds, where the thickness of Pt could be precisely controlled in the range of 1–10 atomic layers ( n =1–10) by adjusting the amount of Pt precursor.…”

A gold nanoparticle-single-chain fragment variable antibody as an immunoprobe for rapid detection of morphine by dipstick

“…21,22 The resonance properties of AuNPs generate oscillation and scattering of conductive electrons. The resonance properties depend on the size, shape, and refractive index of AuNPs.…”