2020, Langer, Judith, de Aberasturi, Dorleta Jimenez, Aizpurua, Javier, Alvarez-Puebla, Ramon A., Auguié, Baptiste, Baumberg, Jeremy J., Bazan, Guillermo C., Bell, Steven E.J., Boisen, Anja, Brolo, Alexandre G., Choo, Jaebum, Cialla-May, Dana, Deckert, Volker, Fabris, Laura, Faulds, Karen, de Abajo, F. Javier García, Goodacre, Royston, Graham, Duncan, Haes, Amanda J., Haynes, Christy L., Huck, Christian, Itoh, Tamitake, Käll, Mikael, Kneipp, Janina, Kotov, Nicholas A., Kuang, Hua, Le Ru, Eric C., Lee, Hiang Kwee, Li, Jian-Feng, Ling, Xing Yi, Maier, Stefan A., Mayerhöfer, Thomas, Moskovits, Martin, Murakoshi, Kei, Nam, Jwa-Min, Nie, Shuming, Ozaki, Yukihiro, Pastoriza-Santos, Isabel, Perez-Juste, Jorge, Popp, Juergen, Pucci, Annemarie, Reich, Stephanie, Ren, Bin, Schatz, George C., Shegai, Timur, Schlücker, Sebastian, Tay, Li-Lin, Thomas, K. George, Tian, Zhong-Qun, Van Duyne, Richard P., Vo-Dinh, Tuan, Wang, Yue, Willets, Katherine A., Xu, Chuanlai, Xu, Hongxing, Xu, Yikai, Yamamoto, Yuko S., Zhao, Bing, Liz-Marzán, Luis M.

The discovery of the enhancement of Raman scattering by molecules adsorbed on nanostructured metal surfaces is a landmark in the history of spectroscopic and analytical techniques. Significant experimental and theoretical effort has been directed toward understanding the surface-enhanced Raman scattering (SERS) effect and demonstrating its potential in various types of ultrasensitive sensing applications in a wide variety of fields. In the 45 years since its discovery, SERS has blossomed into a rich area of research and technology, but additional efforts are still needed before it can be routinely used analytically and in commercial products. In this Review, prominent authors from around the world joined together to summarize the state of the art in understanding and using SERS and to predict what can be expected in the near future in terms of research, applications, and technological development. This Review is dedicated to SERS pioneer and our coauthor, the late Prof. Richard Van Duyne, whom we lost during the preparation of this article.

2023, Aziz, Azaam, Nauber, Richard, Sánchez Iglesias, Ana, Tang, Min, Ma, Libo, Liz-Marzán, Luis M., Schmidt, Oliver G., Medina-Sánchez, Mariana

Micro-and nanorobots have the potential to perform non-invasive drug delivery, sensing, and surgery in living organisms, with the aid of diverse medical imaging techniques. To perform such actions, microrobots require high spatiotemporal resolution tracking with real-time closed-loop feedback. To that end, photoacoustic imaging has appeared as a promising technique for imaging microrobots in deep tissue with higher molecular specificity and contrast. Here, we present different strategies to track magnetically-driven micromotors with improved contrast and specificity using dedicated contrast agents (Au nanorods and nanostars). Furthermore, we discuss the possibility of improving the light absorption properties of the employed nanomaterials considering possible light scattering and coupling to the underlying metal-oxide layers on the micromotor’s surface. For that, 2D COMSOL simulation and experimental results were correlated, confirming that an increased spacing between the Au-nanostructures and the increase of thickness of the underlying oxide layer lead to enhanced light absorption and preservation of the characteristic absorption peak. These characteristics are important when visualizing the micromotors in a complex in vivo environment, to distinguish them from the light absorption properties of the surrounding natural chromophores.

2019, Kuttner, Christian, Höller, Roland P. M., Quintanilla, Marta, Schnepf, Max J., Dulle, Martin, Fery, Andreas, Liz-Marzán, Luis M.

The optical properties of nanoparticle assemblies can be tailored via hybridization of plasmon modes. Isotropic core/satellite superstructures made of spherical nanoparticles are known to exhibit coupled modes with a strongly scattering (radiative) character, and provide hot spots yielding high activity in surface-enhanced Raman scattering (SERS). However, to complement this functionality with plasmonic heating, additional absorbing (non-radiative) modes are required. We introduce herein anisotropic superstructures formed by decorating a central nanorod with spherical satellite nanoparticles, which feature two coupled modes that allow application for both SERS and heating. On the basis of diffuse reflectance spectroscopy, small-angle X-ray scattering (SAXS), and electromagnetic simulations, the origin of the coupled modes is disclosed and thus serves as a basis toward alternative designs of functional superstructures. This work represents a proof-of-principle for the combination of high SERS efficiency with efficient plasmonic heating by near-infrared irradiation.