Applications of gold nanoparticles in virus detection

Draz, Mohamed Shehata; Shafiee, Hadi

The nanoscale size and the relatively simple structure of viruses tend to impose technical difficulties in establishing wide-use and long-term systems for virus detection. The small size of viruses increases the difficulty of their isolation and visualization compared with other microbes, such as bacteria and fungi that can be readily examined using ordinary light microscopes. Only electron microscopy (EM) with a high-magnification power of ~100,000× can allow the direct visualization of viruses and the study of their structures [14, 15] . Therefore, EM remains crucial for many purposes in virus research. However, EM is certainly inappropriate for routine clinical diagnosis because of the required time and cost, as well as many safety concerns. Furthermore, although the simple structure of virus particles allows the features of diagnostic relevance to be easily defined and tested, it presents limitations on the use of their characteristics for practical applications, especially with the increasing number of discovered viruses and recorded viral infections [14, 16, 17] . In addition, this structural simplicity confers viruses with rapid rates of spontaneous adaptation and evolution that may occur through direct genetic mutation, genetic substitution, or recombination. In this way, viruses not only outpace our attempts to develop sustainable control strategies but also raise more questions about the appropriateness and validity of current diagnostic techniques for long-term use [18, 19] .