PCA-assisted direct diagnosis of Aβ proteins for Alzheimer's disease using non-metallic SERS platform of graphitic carbon nitride@metal-organic framework

Abstract

Here, we explored a non-metallic surface enhanced Raman scattering (SERS) platform based on graphitic carbon nitride@metal-organic framework (g-C₃N₄@MOF) for the sensitive direct diagnosis of Aβ proteins, assisted by principal component analysis (PCA). By systematically optimizing the deposition voltage and time, we successfully achieved a uniform coating of g-C₃N₄ nanosheets over a large-area copper foil during the initial electrodeposition step. Subsequently, a homogeneous layer of flower-like MOF structures was deposited onto the g-C₃N₄ nanosheets through a secondary electrodeposition process. This cooperation of g-C₃N₄ nanosheets and flower-like MOF not only significantly enlarged the effective area for molecular enrichment but also promoted charge transfer through energy-level matching between the two materials. The characteristic SERS spectra of Aβ40 and Aβ42, enhanced by the g-C₃N₄@MOF composite substrate, were recorded and classified using PCA to extract informative features of these important biomarkers. This research exploits a new avenue for the clinical assay of neurodegenerative diseases by extracting informative features of key biomarkers.