Citrate-Capped Platinum Nanoparticle as a Smart Probe for Ultrasensitive Mercury Sensing

Abstract

An easily prepared platinum nanoparticle (PtNP) probe for the sensitive and selective detection of Hg(2+) ions is developed here. The PtNPs with an average size of approximately 2.5 nm were prepared by a reduction method with sodium borohydride and trisodium citrate serving as reductant and stabilizer, respectively. The resulting PtNPs could catalyze the reduction of Hg(2+) by surface-capping citrate. The effect of Hg(2+) uptake implies amalgam formation, which leads to remarkable inhibition of the peroxidase-like activity of citrate-capped PtNPs. On the basis of this effect, a colorimetric mercury sensor was established through the use of citrate-capped PtNPs to catalyze the colorimetric system of 3,3',5,5'-tetramethylbenzidine (TMB) and H2O2. The high specificity of the Hg-Pt interaction provides the excellent selectivity for Hg(2+) over interfering metal ions. The sensitivity of this smart probe to Hg(2+) is extremely excellent with a limit of detection (LOD) as low as 8.5 pM. In view of these advantages, as well as the cost-effectiveness, minimized working steps, and naked-eye observation, we expect that this colorimetric sensor will be a promising candidate for the field detection of toxic Hg(2+) ions in environmental, biological, and food samples.

Electrochemical detection of carcinoembryonic antigen based on silver nanocluster/horseradish peroxidase nanocomposite as signal probe

“…The large specific surface area and good biocompatibility of nanomaterials have been utilized to immobilize biomolecues [5,6]. On the other hand, the signal enhancement associated with the use of nanomaterial-biomolecue assemblies provides the basis for ultrasensitive detection of analyte targets [7][8][9]. Among the different kinds of nanomaterials, noble metal based nanomaterials, such metal nanoparticles, metal nanorod and metal nanowire have attracted significant research interest due to the unique optical and electrical properties [10,11].…”

Spectrophotometric determination of mercury(II) ions based on their stimulation effect on the peroxidase-like activity of molybdenum disulfide nanosheets

“…To further demonstrate the effect of surface charge on Hg 2+ effect on the peroxidase-like activity, Cit-Pt NPs and Cit-Au NPs, respectively, were synthesized following the literature methods [24,26]. As documented, Cit-Pt NPs showed Hg 2+ -inhibition effect; however, interestingly, Cit-Au NPs exhibited Hg 2+ -stimulation effect.…”

“…Herein, inspired by the stimulation or inhibition effect on the peroxidase-like activity of various nanomaterials by heavy metal ions [24][25][26][27][28][29], we explored a spectrophotometric assay for the determination of Hg(II), based on its stimulating effect on the peroxidase-like activity of MoS 2 -NSs. The MoS 2 -NSs are found to act as a peroxidase mimic, capable of effectively oxidizing the substrate 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H 2 O 2 .…”

Peroxidase-like activity of nanocrystalline cobalt selenide and its application for uric acid detection

“…Zhuang et al porous platinum nanoparticles on graphene oxide, 6 graphene quantum dots, 7 citrate-capped platinum nanoparticles, 8 AgX nanoparticles, 9 platinum nanoparticles in bovine serum albumin scaffold, 10 and gold nanoparticles. 11,12 Nanoscale peroxidase mimics possess several advantages over naturally occurring peroxidase enzymes, including almost-unchanged catalytic activity over a wide range of pH and temperatures, low cost, tunable catalytic activities, as well as ease of storage and treatment.…”