DNA-Associated Synthesis of Gold Nanoparticles by Gas-Liquid Interfacial Pulse Discharge Plasma

A gas-liquid interfacial discharge plasma is used for the DNA-associated synthesis of water-soluble gold nanoparticles (AuNPs) by reducing gold (III) from aqueous chloroauric acid trihydrate. The plasma is generated by a pulse power source, which can avoid the instability of DC discharges at high pressures. The high discharge current ($\sim $ampere) offers a basis for the high rate synthesis of AuNPs. Single-stranded DNA is used as the stabilizing agent since DNA molecules can be bound to the gold surface. A red shift of surface plasmon resonance (SPR) absorption of AuNPs is observed when the DNA-stabilized AuNPs are mixed with a solution including complementary DNA, which means there is aggregation of AuNPs due to the hybridization of DNA. We also synthesize AuNPs associated with various kinds of DNA such as 30-base guanine G$_{30}$, adenine A$_{30}$, cytosine C$_{30}$, and thymine T$_{30}$. It is found by comparing the intensities of SPR peaks of AuNPs after extracting them from as-synthesized samples by centrifugation that G$_{30}$ and A$_{30}$ DNA have stronger stabilizing ability for AuNPs than that of T$_{30}$ and C$_{30}$ DNA.