Kazuki Nagata
Toyo University, Japan
Title: Butterfly wing scales as a model template for SERS applications
Biography
Biography: Kazuki Nagata
Abstract
We will discuss exploitation of naturally-existing nanostructures for bio-analytical techniques, specifically surface-enhanced Raman spectroscopy (SERS). Raman spectroscopy is one of the few analytical techniques capable of giving information on chemical structures without need to place the sample in a vacuum, making it well suited for on-site inspection of chemical species as in environmental monitoring, forensic sciences and quality control. There are already a number of commercial vendors selling SERS substrates, but the price needs to be reduced significantly in order to make this technique widely used. Our group has been investigating: Random-MFON structures whereby randomly adsorbed SiO2 nanospheres are coated with a noble metal and; silver dendrites grown from surface-adsorbed base metal nanoparticles in a AgNO3 solution. Here, we report on yet another method based on exploitation of scales of butterfly wings. We found that coating of butterfly wing scales, characterized by intrinsic nanostructures, with silver gives rise to a surface capable of showing SERS effects. While effectiveness depends on the butterfly species, precise scales within a single wing, the amount of deposited silver etc., there is a surprising uniformity in SERS signal intensities when these parameters are selected appropriately. By exploiting naturally-existing nanostructures, we can minimize the number of manufacturing steps, thus, reducing the overall cost. We can also obtain basic information on secret as to what makes a particular nanostructure work by selectively altering the underlying nanostrucures. This would give us an option of artificially recreating the crucial nanostructures.