A Review of Gold and Silver Nanoparticle‐Based Colorimetric Sensing Assays

Abstract

The nanoparticle colorimetric-based methods have been extensively used for rapid detection, however there are few limitations which can be kept under control or avoided by understanding the crucial parameters involved in these reactions. This review addresses the main parameters that influence colorimetric-based methods and provides a rational classification of the current approaches, by focusing particularly on gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs). The AgNP and AuNP-based colorimetric assays can be very efficient and sensitive especially for biomolecule identification and for metal ion detection in environmental screening. Specifically, this review highlights the detection of metal ions through their coordination with nanoparticle stabilizing ligands. The review also addresses various approaches based on label-free aptasensors to better understand their role as smart colorimetric sensing devices.

Latest advances in combining gold nanomaterials with physical stimuli towards new responsive therapeutic and diagnostic strategies

“…Thus, the simplest implementation of LSPR sensing is the use of AuNMs as a functional component of colorimetric assays both in liquid (homophase methods) and solid (dot immunoassay and immunochromatography) phase [1]. In these assays, AuNMs are conjugated with a bioactive moiety capable of binding with high-affinity specific analytes present in a solution [157,158], such as biomolecules (e.g., proteins [159] or toxins [160]), small molecules (oligonucleotides [161]), ions (e.g., selenium [162]), or diseased cells (e.g., acute leukemia cells [163]). AuNMs-based optical sensors can also be used to detect specific antigens within the cellular compartments [164,165].…”

Chiral Ag and Au Nanomaterials Based Optical Approaches for Analytical Applications

“…However, they are usually less sensitive. The absorption sensing systems are usually based on analyte induced aggregation of the Ag/Au nanomaterials, meanwhile, the CD sensing systems are sensitive to detect the structural changes in the nanomaterials. Thus, CD sensing systems are usually more sensitive; for example, an assay provides LOD down to a m for DNA has been reported .…”

High‐Performance Biosensing Systems Based on Various Nanomaterials as Signal Transducers

“…Noble MeNPs such as Au, Ag, and Pt NPs have unique optical properties that are characterized by a strong plasmonic absorbance (Abs) at a specific wavelength, which originates from the localized surface plasmon resonance (LSPR) effect . The wavelength of this plasmonic absorbance can be tuned through self‐assembly processes and the resulting plasmonic coupling interactions, and many researchers have the modulated plasmonic properties via structural alteration of Au or Ag NPs with biomolecules, such as peptides, proteins, and DNA .…”

“…Noble MeNPs such as Au, Ag, and Pt NPs have unique optical properties that are characterized by a strong plasmonic absorbance (Abs) at a specific wavelength, which originates from the localized surface plasmon resonance (LSPR) effect. [34][35][36] The wavelength of this plasmonic absorbance can be tuned through self-assembly processes and the resulting plasmonic coupling interactions, [37][38][39] and many researchers have the modulated plasmonic properties via structural alteration of Au or Ag NPs with biomolecules, such as peptides, proteins, and DNA. [40][41][42][43][44] This tuning ability indicates that the plasmonic absorbance can be used as a signal transducer for the biosensing of target biomolecules because its wavelength changes with the biomolecule-induced self-assembly of MeNPs.…”