From identifying of viruses, to drugs, to explosives, the surface-enhanced Raman spectroscopy (SERS) technique can do it all and with great sensitivity and accuracy. This is why it is widely used in industry. In SERS, light is shone on a nanosurface containing a chemical or biological analyte. The light reflected after interaction with the analyte then hits a detector which maps the received signal to known compounds to identify the analyte. The interaction of the light with the nanosurface enhances its scattering from the analyte molecules. Thus, the strength of the signals depends on the morphology of the substrate. But developing effective nanosurfaces is, at present, quite challenging, involving complex and expensive processes and difficulty in obtaining materials that can withstand the high heat and light conditions needed for fabrication.
Now, scientists from Pusan National University, Korea, have developed a method—using a heat resistant polymer called polyimide (PI)—that can easily and rapidly yield SERS nanosurfaces with superior stability and performance at low cost. Their findings are published in the Journal Sensors and Actuators B: Chemical.
Their method comprises a simple two-step process and is carried out in a vacuum chamber with custom-built sputtering apparatus. First the surface of a PI nanofilm is etched via plasma etching in the presence of argon ions to form a nanotextured surface consisting of nanopillars. The PI nanopillars are then uniformly coated with silver (Ag) nanoparticles (NPs) through a standard deposition process. The vacuum prevents any external contamination, yielding highly uniform AgNP/PI nanostructures ready as platforms for analytes.
By controlling the time taken from PI etching to AgNP deposition, the scientists were able to control both the nanopillar density and the Ag coating thickness to arrive at a platform with the best morphology for an optimal signal intensity. They even tested the performance of this platform experimentally, for the detection of a chemical called RhB, and found it reliable.
“Our research shows that it is possible to fabricate a sensor with superior performance at a lower cost than current noble-metal-based SERS sensors,” says Prof. Young-Rae Cho, who led the study. Further, the scientists expect this fabrication process to significantly expand the scope of applicability of the SERS technique. “Our method could facilitate the dissemination of disease diagnosis kits in households and enable even more widespread use of excellent detection sensors in the virus, explosives, and drug detection industries,” remarks Prof. Cho, looking towards a much more hopeful future.
Authors: Jun-Hyung Sim (1), Soo Hyun Lee (2) Jun-Yeong Yang (2), Won-Chul Lee (2), Chae Won Mun (2), Seunghun Lee (2), Sung-Gyu Park (2)*, Young-Rae Cho (1)*
- Pusan National University, Republic of Korea
- Korea Institute of Materials Science, Republic of Korea
About Pusan National University
Pusan National University, located in Busan, South Korea, was founded in 1946, and is now the No. 1 National University of South Korea in research and educational competency. The multi-campus university also has other smaller campuses in Yangsan, Miryang, and Ami. The university prides itself on the principles of truth, freedom, and service, and has approximately 30,000 students, 1200 professors, and 750 faculty members. The university is composed of 14 colleges (schools) and one independent division, with 103 departments in all.
About the author
Prof. Young-Rae Cho received his Ph.D. degree from University of Stuttgart in 1994. Now, he is a professor and the dean of the College of Engineering at Pusan National University. His research interests include superhydrophobic structures and interface science.
Jun-Hyung Sim received his Bachelor’s degree from Pusan National University (PNU) in 2020. Now, he is studying for his Master’s degree in the division of materials science and engineering at PNU. His research interests focus on 3D nanopatterning and biosensors.
Sung-Gyu Park currently a director of Nano-Bio Convergence Department in Korea Institute of Materials Science. He has authored one book chapter and over 90 articles, and has more than 30 inventions. His research interests include nanoplasmonics, surface-enhanced Raman spectroscopy, 3D nanopatterning, plasmon-enhanced fluorescence, and biosensors.
Sensors and Actuators B Chemical
Method of Research
Subject of Research
Plasmonic hotspot engineering of Ag-coated polymer substrates with high reproducibility and photothermal stability
Article Publication Date
There are no conflicts of interest to declare.