Gold nanoparticles as sensitive optical probes

Abstract

Gold nanoparticles (Au NPs) have become one of the most popular materials for sensing of analytes of interest in the last decade, mainly because of their ease in preparation and conjugation, stability, biocompatibility, and size-dependent optical properties. We have witnessed many sensitive and selective Au NP based optical systems for the quantitation of metal ions, anions, proteins, and DNA, based on analyte induced changes in their absorption, fluorescence, and scattering. In this tutorial review, we briefly discuss wet chemical approaches for the preparation of Au NPs. Sensing mechanisms and strategies of Au NP based optical systems are provided to show basic concepts in designing sensitive and selective sensing systems. Strategies for signal amplification applied in Au NP based systems are emphasized for the analysis of trace amounts of analytes in real samples. Many excellent Au NP based optical sensing systems are discussed to highlight their practicality for the analysis of complicated biological and environmental samples. The tutorial review ends with the discussion of the challenges and future trends of Au NP based optical sensing systems.

Possibilities and Challenges for Quantitative Optical Sensing of Hydrogen Peroxide

“…The oxidation (degradation) of Ag-NP (Ag • to Ag + ) by H 2 O 2 was utilized for several different detection schemes [77,78,89]; however, one paper concludes that the oxidation of Ag-NPs is in fact much faster with OCl − than with H 2 O 2 [90], thus oxidation-based Ag-NPs might not always be suitable for measuring H 2 O 2 . Gold nanoparticles (Au-NP) are also frequently applied in optical sensing due to their biocompatibility, size-tunable optical properties, stability, and ease of preparation and conjugation [81]. They can be used with [82] or without [86] surface modifications; however, they can also be used to quench the luminescence of an inert material by H 2 O 2 initiated biocatalytic growth of Au-NP from Au nano-seeds [84].…”

“…Heavy metals are frequently used as base for nanoparticles, such as silver [76][77][78][79][80], gold [81][82][83][84][85][86], cadmium, zinc or tellurium [87,88]. Silver nanoparticles (Ag-NP) in general have a broad field of application, as they are antibacterial, antiviral, and antifungal.…”

Recent Advances on Inorganic Nanoparticle-Based Cancer Therapeutic Agents

“…For example, gold nanoparticles show wide applications in the detection of small analytes and biomolecules via surface modification [6]. Semiconducting quantum dots display great potential in bioimaging because of their high fluorescence quantum yield and wide emission range [7].…”

Selective and sensitive colorimetric determination of cobalt ions using Ag–Au bimetallic nanoparticles

“…Plasmonic nanoparticle-based colorimetric methods for detecting analytes have gained growing interest because of their simplicity, low cost, rapid response and expensive instrumentfree characters. [1][2][3][4] Various analytes including metal ions, 5,6 proteins, 7 DNA, 8,9 glucose, 10 H 2 S 11 could be determined through elaborately designed strategies with high sensitivity and selectivity. Monometallic nanoparticles, in particular gold nanoparticles and silver nanoparticles, are the two most selected materials for developing colorimetric assays due to their prominent characteristics.…”