Multifunctional plasmonic gold nanoisland films for enhanced cell theranostics through photothermal therapy and surface-enhanced Raman scattering detection

Plasmonic gold nanomaterials have numerous applications in biomedical therapy and sensing. In this work, plasmonic gold nanoisland films (AuNIFs) were demonstrated to have significant applications in photothermal therapy and surface-enhanced Raman scattering (SERS) detection. A seed-mediated growth method was used to fabricate AuNIFs on glass substrates. Material Characterizations confirmed the successful preparation of AuNIFs. Surface plasmon resonance produced a broad UV-Vis absorption spectrum (400–1000 nm). Under 808-nm near-infrared (NIR) laser irradiation (1.5 mW/cm2), AuNIFs reached 65°C, generating sufficient heat to kill Vero epithelial cells. The cell death rate of Vero cells under laser irradiation was estimated to be 1.38 times higher than that in the absence of laser irradiation. The AuNIFs exhibited stable photothermal performance under cyclic laser exposure for 10 min and outperformed conventional photothermal therapy in eradicating Vero cells. Compared to bare glass slides, AuNIFs promoted more-confluent Vero cell growth. Additionally, the AuNIF platform enhanced the Raman signal of Vero cells according to a SERS analysis. Fluorescence imaging confirmed laser-induced cell death, as indicated by green fluorescence. By integrating photothermal therapy and SERS detection, AuNIFs demonstrated strong potential as multifunctional substrates for cell theranostics.