Advancing Cultural Heritage Analysis: How Anisotropic Nanostructures Are Revolutionizing Raman and SERS Spectroscopy

A recent study conducted by researchers at Sapienza University of Rome investigated how to use anisotropic nanostructures can improve material characterization of cultural artifacts, including artwork. This review article was published in the Journal of Cultural Heritage, and it highlights the growing use and advancements in Raman spectroscopy and SERS in analyzing cultural artifacts (1). Anisotropic nanostructures are gold or silver nanoparticles with asymmetric shapes, used to enhance the Raman signal by concentrating the electromagnetic field at the particle tips or edges, leading to highly sensitive molecular detection of sample spectra.

Living Room Interior with Artistic Decor. Generated with AI. | Image Credit: © Helen Marlen - stock.adobe.com

Cultural heritage artifacts are often hundreds (and even thousands) of years old. As a result, they are often fragile, requiring careful handling to not destroy them. Analytical techniques equally need to be as non-destructive. As a result, Raman spectroscopy and SERS have routinely been used in this space because they are non-destructive techniques, which means they do not destroy the sample when being used to conduct the analysis (1–3).

However, Raman spectroscopy does have limitations. Fluorescence interference is a big problem (1). SERS addresses these concerns by utilizing metallic nanostructures, which significantly enhance the Raman signal while mitigating fluorescence interference.

Metallic nanoparticles have been used effectively in clinical applications such as for drug delivery systems, but they also have a role to play in cultural heritage studies. Metallic nanoparticles have properties finely tuned by variations in shape, size, and composition (1). In this review article, the authors discuss how anisotropic nanostructures are better than their spherical counterparts, and how they amplify SERS hotspots and intensify plasmonic bands (1). By performing these two functions, they help detect small amounts of compounds that would have normally remained undetectable (1).

To understand why metallic nanoparticles are a significant innovation in this application, it is important to understand how the improve on traditional metal nanoparticles. Unlike traditional metal nanoparticles, which require high concentrations to achieve significant signal enhancement, highly anisotropic nanostructures naturally generate a broader distribution of hotspots, making them effective for the ultra-sensitive detection of cultural heritage materials (1). This intrinsic property allows researchers to analyze dyes and pigments at trace levels (1). Because pigments and dyes often tell historians and cultural heritage professionals details about the civilization the artifact originated from, it is important that analytical techniques are able to analyze these pigments at the lowest levels possible.

Despite these advantages, the application of anisotropic nanostructures in cultural heritage SERS analyses remains relatively unexplored. According to the review, only a handful of studies have investigated the potential of these nanomaterials in this context (1).

There are also a couple key limitations in applying metallic nanoparticles for this purpose. Traditional SERS techniques often require direct contact with the artifact, which is not always feasible when dealing with rare or fragile objects. That is why the review article discusses recent advancements in micro-invasive sampling methods, which are thought to be a potential solution to this problem (1).

Another critical limitation of anisotropic nanostructures is their complex synthesis. Producing these nanomaterials with high yields and stability remains an ongoing challenge because synthesis protocols are often intricate and require precise control over reaction conditions (1). The authors write that work has been done to improve yields of anisotropic particles, such as nanocubes, nanotriangles, and nanorods, and the results have led to significant improvements (1). These refinements bring researchers closer to optimizing SERS applications in the field of cultural heritage.

Moving forward, continued research into the synthesis, stability, and scalability of anisotropic nanostructures will be crucial in fully harnessing their capabilities. Additionally, integrating SERS with complementary techniques—such as optical microscopy and fiber optics—may further enhance its applicability, allowing for even more precise and non-invasive analyses (1).

References

1. Zumpano, R.; Simonetti, F.; Genova, C.; Mazzei, F.; Favero, G. Raman Spectroscopy and SERS: Recent Advances in Cultural Heritage Diagnostics and the Potential Use of Anisotropic Metal Nanostructures. J. Cul. Herit. 2025, 71, 282–301. DOI: 10.1016/j.culher.2024.12.010
2. Workman, Jr., J. Cutting-Edge Raman Spectroscopy Applied for Forensic and Heritage Studies. Spectroscopy. Available at: https://www.spectroscopyonline.com/view/cutting-edge-raman-spectroscopy-applied-for-forensic-and-heritage-studies (accessed 2025-01-30).
3. Rousaki, A.; Vandenabeele, P. In Situ Raman Spectroscopy for Cultural Heritage Studies. J. Raman Spectrosc. 2021, 52 (12), 2178–2189. DOI: 10.1002/jrs.6166