Anguang has made new progress in the research of high-sensitivity fiber SERS probes

Anguang has made new progress
in the research of high-sensitivity fiber SERS probes.

Recently, the research group of Mao Qinghe of Anhui Institute of Optics and Mechanics cooperated with the research group of Meng Guowen of the Institute of Solid State Physics to make new progress in the preparation of high-sensitivity fiber SERS probes: a new method for preparing high-sensitivity optical fiber SERS probes by laser-induced self-assembly was proposed, and the prepared optical fiber SERS probes showed a wide range of application prospects
in the fields of trace, long-range and rapid detection of PCBs, pesticide residues, biochemical warfare agents, etc.

The optical fiber SERS probe combining micro-scale optical fiber technology and nano-scale SERS effect has the advantages of compact, flexible and remote detection, and because the SERS sensitive regions participate in the interaction process, SERS detection repeatability is good, which has attracted widespread attention
in recent years.
Generally, researchers use chemical modification fixation, liquid phase synthesis, photo-induced chemical deposition and other chemical methods, or use vapor deposition, nanosphere etching, micro-nano processing and other physical methods to prepare precious metal nanostructures on the surface of optical fibers to form optical fiber SERS
probes 。 However, most of the nanostructures prepared by chemical preparation methods are noble metal nanoparticle island membranes, and the SERS enhancement factor is relatively weak (about 104 magnitude).
Although the SERS enhancement factor (106-108 magnitude) of the probes prepared by physical methods is expensive, the preparation process is complex, time-consuming, and difficult to meet the practical needs
of batch preparation.
Therefore, the development of new optical fiber SERS probe preparation methods has always been a research hotspot in this field, and it is also the key to
promoting the practical application of optical fiber SERS probe.

In view of the above problems, the two research groups tried a large number of preparation schemes, and finally proposed a simple and low-cost laser-induced self-assembly method to realize the rapid and repeatable preparation
of high-sensitivity fiber SERS probes.
The new preparation method by lifting the optical fiber from the pre-prepared nanoparticle sol to the formation of a specific bending surface structure near the liquid surface, under induced laser irradiation, the thermal effect of the precious metal nanoparticles at the bending surface and the electromagnetic interaction between the nanoparticles will make the nanoparticles self-assemble on the end face of the fiber and form a cluster structure, thereby greatly enhancing the local field
。 The optical fiber SERS probe prepared by this method shows extremely high detection sensitivity and excellent detection repeatability: using portable Raman spectrometer, p-ATP high-sensitivity SERS detection of 10-10M is achieved under 2s integration time; SERS spectral detection repeatability: relative standard deviation RSD<2.
8%, probe preparation repeatability: RSD<7.
8
%.
This highly sensitive and repeatable fiber optic SERS probe has potential application prospects
in the remote/on-site detection of environmental pollutants, biomedical in vivo analysis, real-time monitoring of chemical reaction processes, and even some quantitative detection fields.
The results of the research have applied for national invention patents and were published in the latest issue of the journal Nanoscale as a cover article
.
According to Dr.
Ye Liu, the first author of the paper, they are currently developing a portable SERS analysis instrument
based on this new probe technology.
This research work has been supported
by the National Major Scientific Research Program of China and the National Natural Science Foundation of China.