Femtosecond Laser–Fabricated Bowl‐Shaped Surface‐Enhanced Raman Scattering Platform for Multibiomarker Analysis of Acute Myocarditis Using Fuzzy Logic

ABSTRACT Biomarkers for acute myocarditis (AM) are commonly used in clinical diagnosis, but their ultralow concentrations in blood are challenging to be detected in the early stage. This study presents a novel bowl‐shaped surface‐enhanced Raman scattering (SERS) substrate with high‐performance, prepared via one‐step hydrofluoric acid etching of SiO ₂ microspheres, 515 nm femtosecond‐laser reduction of gold ions, and nanosecond‐laser reshaping of gold nanoparticles (AuNPs). In particular, 500 nm SiO ₂ microspheres were etched with a hydrofluoric acid solution to form a uniform microbowl array, and AuNPs were synthesized in situ on the SiO ₂ microbowls via irradiation with a femtosecond laser. Subsequently, the AuNPs were reshaped into nanorods using a nanosecond laser. The resulting bowl‐shaped AuNP@SiO ₂ substrate showed a SERS enhancement factor of 10 ⁶ and a limit of detection of 3.84 × 10 ⁻⁸ M, as evaluated on Rhodamine 6G. Notably, the limits of detection of the AM biomarkers were lower than 6 pg/mL, enabling the accurate detection of their trace quantities. For AM prediction, a fuzzy logic model was trained, enabling the accurate and quantitative analysis of biomarkers, with a mean relative error of less than 25.7%. Thus, the proposed SERS platform is a reliable tool for the early noninvasive diagnosis of AM.