Gold and Silver Nanomaterial‐Based Optical Sensing Systems

Abstract

REVIEWGold and silver nanomaterials (NMs) such as nanoparticles (NPs) and nanoclusters (NCs) possessing interesting optical properties have become popular sensing materials. With strong surface plasmon resonance (SPR) absorption, extraordinary stability, ease in preparation, conjugation, and biocompatibility, Au NPs are employed to develop sensitive and selective sensing systems for a variety of analytes. However, small sizes of Au and Ag NCs with interesting photoluminescence (PL) properties are used in many PL-based sensing systems for the detection of important analytes. In addition, many bimetallic AuM NMs possessing strong catalytic activity are used to develop highly sensitive fl uorescent sensors. This review article is categorized in four sections based on the NMs used in the sensing systems, including Au NPs, bimetallic AuM NMs, Au NCs, and DNA-Ag NCs. In each section, synthetic strategies and optical properties of the NMs are provided briefl y, followed by emphasis on their analytical applications in the detection of small molecules, metal ions, DNA, proteins, and cells. Current challenges and future prospects of these NMs-based sensing systems will be addressed.

Engineering noble metal nanomaterials for environmental applications

“…71 Among these hazardous pollutants (e.g., heavy metal ions, pesticides, dyes, toxic chemicals, pathogens, nanomaterials, and contaminants), 72,73 heavy metal ions have attracted the most attention due to their serious threat to human health and the environment. 74 For an accurate quantification of these heavy metal ions, various optical sensors constructed from NMNs, 22,69,75,76 organic dyes, 77,78 and fluorescent polymers, 79 have been demonstrated. Among the functional materials used for the sensor design, NMNs are the most attractive due to their intriguing physical and chemical properties, including size and shape dependent optical properties, high surface area, good stability, and good biocompatibility.…”

Portable low-cost instrumentation for monitoring Rayleigh scattering from chemical sensors based on metallic nanoparticles

“…The LED-spectral sensor allows acquiring a full scattering spectrum and thus monitoring RRS ratios at different wavelengths without any change in the optical setup. While the spectral sensor detection is currently limited to 380–700 nm, this wavelength range is sufficient for the implementation of chemical sensors based on AuNPs and AgNPs, whose LSPR bands fall in the visible spectrum 4 , 7 . In contrast, measuring different wavelength ratios with the LED dual-detector photometer requires changing the optical filters.…”

Galectin-1 protein modified gold (III)-PEGylated complex-nanoparticles: Proof of concept of alternative probe in colorimetric glucose detection

“…Gold-based nanomaterials have been catching much attention in many areas, such as chemistry, physics, materials science, and biosciences, because of their size-and shape-dependent optic, electric, and catalytic properties [1] [2] [3]. Synthesis of spherical gold nanoparticles (AuNPs) involves the chemical reduction of chloroauric acid (HAuCl 4 ) by using sodium borohydride (NaBH 4 ) and sodium citrate as the reducing agents, thus lowering particle size up to 2-10 and 10-40 nm, respectively [4] [5].…”