In this work, fabrication of micro-scale silver interconnecting wires using biological molecules (protein and DNA) served as templates has been successfully demonstrated. The combination of biomolecular templates with nano-size metal particles illustrates the capabilities of this approach to synthesize versatile electronic interconnecting wires....[ Read more ]

In this work, fabrication of micro-scale silver interconnecting wires using biological molecules (protein and DNA) served as templates has been successfully demonstrated. The combination of biomolecular templates with nano-size metal particles illustrates the capabilities of this approach to synthesize versatile electronic interconnecting wires.

In the protein-templated approach, it started with a self-assembled β-sheet-rich amyloid fibrils developed from soluble hen egg white lysozyme. The highly soluble hen egg white lysozyme rapidly converted to form long fibrillar structures with a diameter of 10 nm when it associated with highly concentrated ethanol solution (90%) or acidic solution (pH 2.0) at elevated temperatures. The fibrillar protein templates were subsequently subject to silver ion impregnation and chemical reduction to drive the formation of protein-based silver strands which offered a useful and novel way for nano-electronic fabrications.

In addition to the protein fibril approach, long-chain double-stranded DNA molecules appear to be another attractive biomolecular material used as templates for nano-structure fabrication. In this approach, the formation of silver wires involved the micro-manipulation of DNA molecules into one-dimensional pattern served as a scaffold followed by silver ion deposition in which the positive silver ions were attracted by the negatively charged DNA backbone. The fabrication of silver wires was then accomplished by silver ion reduction treatment using hydroquinone in both alkaline and acidic conditions. Electron micrographs show that the silver wires formed with DNA templates are of more than 10 μm long and approximately 300-500 nm in width. These achievements suggest a useful way of using a template-directed approach to convert natural biomolecules to metallic silver wires which provide applications in electronic industry.