The Preparation Of The Gold Nanoparticle Biological Probes And The Application In The Detection For Heavy Metal Ions

Gold nanoparticles (GNPs) are widely used in a range of applications, including electronics, biosensing, and surface enhanced Raman spectroscopy. GNPs have received great attention in the development of visual sensing schemes because of the surface plasmon resonance (SPR) mechanism based on the binding-induced aggregation of spherical GNPs. The SPR absorbances are extremely sensitive to the nature, size, and shape of the GNPs, their interparticle distances, and the nature of their surrounding media. Recently, GNPs have extensively been employed as analytical probes in biotechnological and chemical systems.Highly fluorescent, water-soluble, few-atom noble metal quantum dots have been created that behave as multi-electron artificial atoms with discrete, size-tunable electronic transitions throughout the visible and near IR. Providing the"missing link"between atomic and nanoparticle behavior in noble metals, these emissive, water soluble Au nanoclusters open new opportunities for biological labels, biosensors, and light emitting sources in nanoscale optoelectronics.In this paper, the detection of heavy metal ions by functionalized gold nanoparticles was studied. All the relative studies are outline as follows.(1) The L-cysteine modified gold nanoparticles can be induced to aggregate quickly under the condition of presence of Hg²⁺, especially with assistance of ultraviolet radiation. The presence of Hg²⁺ can be monitored by colorimetric response of gold nanoparticles. The detection of Hg²⁺ could be realized after measuring the UV-vis spectra with a detection limit of 100 nM. The selectivity of this method has been investigated by other divalent metal ions.(2) The glutathione modified GNPs can be induced to aggregate quickly in the presence of Pb²⁺, especially after adding the solution of 1M NaCl. The detection of Pb²⁺ ion could be realized with a detection limit of 100 nM. The GSH-GNPs can selectively bind Pb²⁺ over other metal ions (Hg²⁺, Mg²⁺, Zn²⁺, Ni²⁺, Cu²⁺, Co²⁺, Ca²⁺, Mn²⁺, Fe²⁺, Cd²⁺, Ba²⁺ and Cr3+), leading to prominent color change. More importantly, this probe was also applied to determine the Pb²⁺ in the lake samples, and the results demonstrate low interference and high sensitivity.(3) A simple, cost-effective yet rapid and sensitive sensor for the detection of Hg²⁺ using bovine serum albumin (BSA) functionalized fluorescent gold nanoparticles was developed. Using this probe, aqueous Hg²⁺ can be detected at 0.1 nM based fluorescence quenching in a facile way, with high selectivity against other metal ions. This probe was also applied to determine the Hg²⁺ in the lake samples, and the results demonstrate low interference and high sensitivity.