DNA-templated Formation Of ZnO Nanoparticles Chains

Fabrication of semiconductor nanoparticles arrays poses a challenge for their unique optical and electronic properties. They can be used to fabricate the components of nanoscale devices such as diode logic gates, bipolar transistors, or optoelectronic transistors. The formation of nanostructures using organism templates has attracted much attention for its efficiency and cheapness. Among biological molecule templates, DNA is recognized as the most frequently used organism due to its strong binding effect with nanoparticles and easily controlled structures.In this research, DNA was used as template to assembly ZnO nanoparticles. Fish sperm DNA and Zn(NO3)2 were mixed in water solution to make complete binding. The electrophoresis experiment confirmed that Zn2+ bound to DNA and decreased the negative charge of DNA. Then the mixture was heated in a water-bath, and DEA solution was added to react with Zn(NO3)2. High resolution transmission electron microscope (HRTEM) images show that nanoparticles formed along DNA template as a chain. XRD is used to certificate that the particles are of ZnO. FTIR confirms that Zn2+ had bond to DNA, and ZnO nanoparticles were still on the DNA template after the reaction.Compact or sparse chains can be obtained by changing the ratio of [Zn2+] to [DNA]. When the ratio increases, the ZnO particles grow larger and closer. As a result the chains tend to be compact. Control experiments with plasmid DNA and with the absence of DNA were also carried out to confirm the template effect of DNA. Necklace-like structures and dispersed ZnO nanoparticles were observed individually. Molecular combing was tried to stretch DNA-ZnO structures on a surface, and AFM was used to observe the result.