- Nanostructure-assisted optical tweezers for microspectroscopic polymer analysis
- Tatsuya Shoji*, Yasuyuki Tsuboi
- Polym. J., 53 (2021), 271-281.
- DOI: 10.1038/s41428-020-00410-w
Raman/fluorescence microspectroscopic analysis of individual polymer chains and nanobeads dissolved in solution will become a powerful analytical method to study their molecular structure and characteristics. With this motivation, we focused on the use of Raman microspectroscopy for optically trapped soft matter. A tightly focused near-infrared laser beam formed a microassembly of thermoresponsive polymer chains such as poly(N-isopropylacrylamide) due to a local photothermal effect and optical force. By using this method, we developed a technique for determining the polymer concentration in a polymer microassembly. Furthermore, we demonstrated a molecular condensation and detection technique based on microassembly on plasmonic nanostructures. For this molecular condensation and detection process, localized surface plasmons play an essential role in the optical force enhancement and local temperature increase around the plasmonic nanostructures. Finally, aiming toward novel manipulation methods of smaller soft nanomaterials, nanostructured semiconductor-assisted (NASSCA) optical tweezers are introduced. In this paper, we reviewed the optical manipulation methods of polymer chains and nanobeads and their applications in analytical chemistry.
https://www.nature.com/articles/s41428-020-00410-w