Sensitive and Selective Gold Nanomaterials Based Optical Probes

Gold nanomaterials (Au NMs) based optical probes have recently attracted considerable attention in the analysis of environmental and biological samples due to their simplicity, sensitivity, and selectivity. Au nanoparticles (NPs) having unique size- and shape-dependent optical properties, high extinction coefficients, and super-quenching capability, have been employed for development of sensitive absorption, fluorescence quenching, and light scattering approaches. On the other hand, small sizes of fluorescent Au nanodots (NDs) have been used for the photoluminescent detection of analytes. Preparation and optical properties of Au NMs are briefly discussed. Au NMs based colorimetric, fluorescent, and light scattering approaches for the detection of metal ion, DNA, and proteins are highlighted with respects to their simplicity in preparation, stability, selectivity, and sensitivity. The advantages and disadvantages of different detection methods for sensing of interesting analytes using functional Au NMs are discussed. DNA-Au NMs are particularly emphasized to show their advantages for the detection of toxic heavy metal ions, specific sequence DNA, platelet-derived growth factor (PDGF), and thrombin.