Logical regulation of the enzyme-like activity of gold nanoparticles by using heavy metal ions

Abstract

In this study we employed self-deposition and competitive or synergistic interactions between metal ions and gold nanoparticles (Au NPs) to develop OR, AND, INHIBIT, and XOR logic gates through regulation of the enzyme-like activity of Au NPs. In the presence of various metal ions (Ag(+), Bi(3+), Pb(2+), Pt(4+), and Hg(2+)), we found that Au NPs (13 nm) exhibited peroxidase-, oxidase-, or catalase-like activity. After Ag(+), Bi(3+), or Pb(2+) ions had been deposited on the Au NPs, the particles displayed strong peroxidase-like activity; on the other hand, they exhibited strong oxidase- and catalase-like activities after reactions with Ag(+)/Hg(2+) and Hg(2+)/Bi(3+) ions, respectively. The catalytic activities of these Au NPs arose mainly from the various oxidation states of the surface metal atoms/ions. Taking advantage of this behavior, we constructed multiplex logic operations-OR, AND, INHIBIT, and XOR logic gates-through regulation of the enzyme-like activity after the introduction of metal ions into the Au NP solution. When we deposited Hg(2+) and/or Bi(3+) ions onto the Au NPs, the catalase-like activities of the Au NPs were strongly enhanced (>100-fold). Therefore, we could construct an OR logic gate by using Hg(2+)/Bi(3+) as inputs and the catalase-like activity of the Au NPs as the output. Likewise, we constructed an AND logic gate by using Pt(4+) and Hg(2+) as inputs and the oxidase-like activity of the Au NPs as the output; the co-deposition of Pt and Hg atoms/ions on the Au NPs was responsible for this oxidase-like activity. Competition between Pb(2+) and Hg(2+) ions for the Au NPs allowed us to develop an INHIBIT logic gate-using Pb(2+) and Hg(2+) as inputs and the peroxidase-like activity of the Au NPs as the output. Finally, regulation of the peroxidase-like activity of the Au NPs through the two inputs Ag(+) and Bi(3+) enabled us to construct an XOR logic gate.

Green synthesis of gold nanoparticles and its application for the trace level determination of painter's colic

“…Lead interferes with the development of the nervous system and is particularly toxic to children, causing potentially permanent learning and behavior disorders. [6][7][8][9][10][11] Metal nanoparticles have attracted particular interest in the detection of Pb 2+ owing to their unique electronic, magnetic, catalytic and optical properties, which are different from bulk metals and dependent on their size and shape. No safe threshold for lead exposure has been discovered, i.e., there is no known sufficiently small amount of lead that will not cause harm to the body.…”

High‐Performance Integrated Enzyme Cascade Bioplatform Based on Protein–BiPt Nanochain@Graphene Oxide Hybrid Guided One‐Pot Self‐Assembly Strategy

“…Pt(IV) ions were directly reduced to PtNPs and PtNPs were anchored to the GO surface mainly through the oxygen functional groups of GO and protein. After the addition of Bi 3+ , strong metallophilic interactions (between Pt and Bi) or the electrostatic attraction (between Bi 3+ and protein) resulted in deposition of Bi 3+ on the PtNP surfaces . Previous studies have demonstrated that polymers might preferentially adsorb on some specific facets of inorganic nanocrystals, resulting in oriented attachment and formation of anisotropic nanostructures .…”

Biophotonic logic devices based on quantum dots and temporally-staggered Förster energy transfer relays

“…[23][24][25][26][27] Typically, MLDs are not like semiconductor-based logic in employing voltages as the input/output (I/O) signals, but instead use chemical or biochemical inputs and electrochemical [28][29][30] or spectroscopic/photonic outputs. 16,20,22,23,[31][32][33][35][36][37][38][39][40][41] By virtue of dipole-dipole coupling between their component molecules, photonic-based MLDs oen support shortrange (<10 nm) internal communication via Förster resonance energy transfer (FRET) which opens up fruitful avenues for logic gate design. Thus, MLDs have been hindered in terms of inherent complexity and function.…”