A research group led by Professor Keisuke Goda of the University of Tokyo Graduate School and colleagues at LucasLand Co., Ltd. have synthesized nanoparticles analogous to Prussian blue, a pigment also known as Hokusai blue or Hiroshige blue that was used in ukiyo-e paintings, and discovered that they can function as a substrate for surface-enhanced Raman spectroscopy (SERS), which has a sensitivity 1 million times higher than conventional spectroscopic analysis methods (Raman spectroscopy).
SERS, a highly sensitive analytical method, has been measured using localized surface plasmon resonance (LSPR) in the gaps (hot spots) of metal nanostructures. However, to solve the problems of poor biocompatibility, durability, uniformity and reproducibility of metal SERS substrates, non-metallic materials such as carbon, semiconductors and dielectrics have been proposed. However, there was a problem that it was difficult to control the SERS performance, which changes depending on the combination of the target molecule and various substrates.
The research group discovered that Prussian blue analogues, which are made by adding different metals to Prussian blue, a coordinated metal complex compound of iron and cyanide, exhibit excellent SERS performance due to the generated crystal defects. Since the SERS performance changes depending on the type of metal, it is possible to control the SERS performance through the generation of crystal defects. In addition, this SERS substrate shows an extremely high enhancement rate (108 times), and is expected to be applied to ultra-high sensitivity analysis of biomolecules, etc.
SERS measurements using Prussian blue analog nanoparticles are highly reproducible, uniform, durable, versatile, and biocompatible, and may overcome problems in conventional chemical analysis, such as the size of the equipment, difficulty of use, and high cost. It is expected that this method will be useful in pioneering new areas of "anywhere, anyone, simple, on-site, low-cost chemical analysis," in areas such as medicine, industry, environmental safety, and criminal investigation.
Paper information:[ACS Nano] Defect-Engineered Coordination Compound Nanoparticles based on Prussian Blue Analogues for Surface-Enhanced Raman Spectroscopy
