Gold Nanoparticles: Synthesis, Stability Test, and Application for the Rice Growth

Aiwu Wang,Yuhong Zheng,Jingping Yu,Yuyu Li,Hoi Pong Ng,Yi Xu,Feng Peng,Fugui Han,Li Fu

doi:10.1155/2014/451232

Abstract

In today’s science, with the use of nanotechnology, nanomaterials, which behave very differently from the bulk solid, can be made. One of the capable uses of nanomaterials is bioapplications which make good use of the specific properties of nanoparticles. However, since the nanoparticles will be used bothin-vivoandin-vitro, their stability is an important issue to the scientists, concern. In this dissertation, we are going to test the stability of gold nanoparticles in a number of media including the biocompatible medium and their behaviors will be illustrated in terms of optical properties change and aggregation degree. Herein, we report the synthesis of gold nanoparticles of different shapes and applications for the rice growth with significant difference. The gold nanoparticles can inhibit the elongation of rice root without inhibiting the germination of rice seeds.

Highlights

Gold nanoparticles (AuNPs) are called colloidal gold or gold colloids
20 μL of 0.01 M silver nitrate was added into the test tube and we waited for 4 seconds before gently mixing it
25 mL of water and a magnetic stir bar were added into a flask and the flask was placed on stirrer and heated to 100∘ C

Summary

Introduction

Gold nanoparticles (AuNPs) are called colloidal gold or gold colloids. Similar to semiconductors, when metals decrease their size from bulk to the nanoscale, they experience quantum confinement effect [1]. The conduction band electrons of the metal nanoparticles will resonate with the electromagnetic field, that is, light, and cause light absorption; this phenomenon is known as surface plasmon resonance [2–5]. At that time, Mie’s theory could only be applied on metal nanoparticles which are much smaller than wavelength of light (about 25 nm) due to the assumption of the theory. The theory shows that plasmon absorption is size independent [7–9]. By the full expression of Mie’s theory, it can be applied to large metal nanoparticles (>25 nm) and can show size dependence of plasmon absorption [10–. In the presence of light, the conduction band electrons of AuNPs oscillate due to surface plasmon resonance. The oscillating electrons interact with the crystal lattice of AuNPs and transfer thermal energy to the lattice. AuNPs are heated up and can further dissipate their thermal energy to the surrounding medium to achieve the heating effect [21]

Experimental Parts

Results and Discussion

Conclusions