Goda Lab

Surface-enhanced Raman spectroscopy (SERS) is a valuable technique for vibrational spectroscopy due to its ability to provide sensitivity several orders of magnitude higher than traditional spontaneous Raman scattering by exciting localized surface plasmon resonance (LSPR) on metal substrates. However, SERS has limitations that make it less reliable for biomedical applications. These limitations include poor measurement reproducibility, non-uniform surface enhancement, and limited compatibility with biological molecules, as well as reduced durability due to its reliance on LSPR-generated "hot spots," significant photothermal heat generation, and susceptibility to oxidation.

We are focused on revolutionizing SERS by designing, fabricating, and utilizing a new class of SERS substrates. Our goal is to address the limitations of conventional SERS substrates, such as poor reproducibility, surface enhancement non-uniformity, compatibility with biological molecules, and durability. To accomplish this, we have developed a metal-free, topologically tailored nanostructure consisting of porous carbon nanowires arranged in an array as a SERS substrate. This substrate provides high signal enhancement due to its strong broadband charge-transfer resonance, high reproducibility, durability, and compatibility with biological molecules due to its fluorescence quenching ability. Additionally, we have developed a wearable SERS device using a gold nanomesh substrate that offers a high density of hot spots, thus improving reproducibility. We are currently developing a new family of carbon-based SERS substrates and exploring their potential biomedical applications.

• L. Liu, S. Noguchi, T. Xiao, S. Karhadkar, K. Hiramatsu, H. Segawa, T. Itoh, J. Qu, K. Takei, and K. Goda, "Highly scalable, wearable surface-enhanced Raman spectroscopy", Advanced Optical Materials 10, 2200054 (2022)
• N. Chen, T. Xiao, Z. Luo, Y. Kitahama, K. Hiramatsu, N. Kishimoto, T. Ito, Z. Cheng, and K. Goda, "Porous carbon nanowire array for surface-enhanced Raman spectroscopy", Nature Communications 11, 4772 (2020)
• P. M. Pancorbo, H. Zhang, X. Yu, T. Xiao, and K. Goda, "Metal-free SERS: where we are now, where we are heading", Europhysics Letters 136, 34001 (2022)