Poly(dopamine)-coated TiO2/SiO2 resonators for the non-plasmonic SERS detection of organic analytes

Year: 2026

Authors: Boontanom A., Moscolari L., Kozma E., Speziani M., Alessandri I., Galeotti F., Vassalini I.

Autors Affiliation: Univ Brescia, Dept Informat Engn, Via Branze 38, I-25123 Brescia, Italy; CNR, Ist Sci & Tecnol Chim Giulio Natta, Via A Corti 12, I-20133 Milan, Italy; Univ Brescia, Dept Mech & Ind Engn, Via Branze 38, I-25123 Brescia, Italy; UdR Brescia, INSTM, Brescia, Italy; INO CNR, Via Branze 38, I-25123 Brescia, Italy.

Abstract: Polydopamine (PDA) is a bioinspired polymer with strong adhesive properties, enabling easy surface functionalization. These abilities have already been exploited to develop advanced plasmonic and hybrid surface-enhanced Raman scattering (SERS) platforms, but the possibility of applying PDA coatings to optimize nonplasmonic SERS substrates has to be explored. Here, we applied PDA coatings to non-plasmonic SERS substrates based on core/shell SiO2/TiO2 micrometric spheres (T-rex), which act as dielectric resonators. Functionalized T-rex substrates were tested for the detection of methylene blue (MB), a conventional Raman probe, and histamine, a food contaminant. Compared to unmodified substrates, the PDA-coated T-rex exhibited a substantial increase in SERS activity and a reduction in detection limits (1 mu M for MB and 0.01 mu M for histamine). This enhancement arises from the insurrection of analyte-surface intermolecular interactions (H-bonds, pi-pi stacking and electrostatic attraction) and from charge-transfer processes mediated by PDA. These results demonstrate that PDA is an effective and versatile modifier to boost the sensitivity of non-plasmonic SERS substrates.

Journal/Review: APPLIED SURFACE SCIENCE

Volume: 720      Pages from: 165249-1  to: 165249-11

More Information: We acknowledge financial support under the National Recovery and Resilience Plan (NRRP) , Mission 4, Component 2, Investment 1.1, Call for tender No. 104 published on 2.2.2022 by the Italian Ministry of University and Research (MUR) , funded by the European Union – NextGenerationEU – Project PolyDOpamine funCTional surfaces for SERS monitORing of FOOD contamination (DrFOOD) – CUP D53D23005520006 – Grant Assignment Decree No. 966 adopted on 30/06/2023.
KeyWords: SERS substrates; Non-plasmonic SERS; Polydopamine; Bioinspired; Histamine
DOI: 10.1016/j.apsusc.2025.165249