Gold Nanoparticles-based Colorimetric Platform For Detection Of Metal Ions

Many metal ions are essential cofactors in several enzyme reactions,and important components to maintain the balance of body system.But several metal ions are biological toxicity,can make people poisoned.Especially heavy metal ions,which are high toxicity with a low dose,difficult to degradation,and easy to accumulate,great harmful to humankind.Gold nanoparticles,have excellent optical property,catalytic property,biocompatibility,high affinity to a variety of substances,etc.,which have attracted great attentions.Surface plasmon resonance effect is affected by the particle size,the degree of dispersion,the surrounding medium and so on.A series of gold sensors have been proposed by taking advantage of red-to-purple color change which arises from surface plasmon resonance changes during aggregation.Gold nanoparticles can be combined with mercury to form a stable Au-Hg amalgam structure,improving the catalytic property,accelerating the speed of color reaction,achieving the aim of object detection.Gold nanoparticles can be combined with magnetic nanomaterials,showing the excellent performance both gold nanoparticles and magnetic nanoparticles at the same time.The composite nanomaterials can be used in some color reactions to detect analyte.In this paper,gold nanoparticles-based colorimetric platforms for detection of metal ions were designed,including the following three parts.?1?Cr³⁺ shows big affinity to phosphate which was functionalized on the surface of gold nanoparticles,resulting in gold nanoparticles agglomeration.According to the shift of surface plasmon resonance,Au-P3O105-NPs can be used for selectively detecting Cr³⁺ and ascorbic acid.?2?Mercury can bind with gold nanoparticles,forming Au-Hg amalgam nanostructure,improving their peroxidase simulates enzyme activity,stimulating the catalytic reaction between TMB and H₂O₂.It can be used for Hg²⁺ and H₂O₂ detection.?3?Gold nanoparticles were immobilized on the surface of Fe₃O₄ nanoparticles,aptamer were functionlized on gold nanoparticles due to great affinity between them,this composite nanostructure can be used for Hg²⁺ detection by forming a stable T-Hg²⁺-T structure in aptamer,then,the color reagent methylene blue can be embedded into the double-stranded DNA,leading to color change of system.