Surface-enhanced Raman spectroscopy for the characterization of filtrate portions of blood serum samples of myocardial infarction patients using 30 kDa centrifugal filter devices

Myocardial infarction (MI) is the leading cause of death and disability worldwide. It occurs when a thrombus forms after an atherosclerotic plaque bursts, obstructing blood flow to the heart. Prompt and accurate diagnosis is crucial for improving patient survival. Surface-enhanced Raman spectroscopy (SERS) offers quick response and excellent resolution for qualitative and quantitative analysis of body fluids, making it a valuable diagnostic tool. This study explores SERS for identifying proteins in blood serum samples from MI patients, focusing on cardiac Troponin I (cTnI), a key biomarker. Due to the small size and low concentration of cTnI, its SERS signal may be weak or absent. To address this, 30 kDa filtering devices are used to obtain filtrate portions of serum samples from cTnI-positive patients and healthy individuals. SERS spectral analysis of these filtrates identifies key SERS bands associated with biomolecular changes related to cTnI levels. Principal component analysis (PCA) effec- tively differentiates SERS spectra from healthy and MI-positive patients. Partial least squares regression (PLSR) quantifies cTnI levels based on SERS features, with a model showing R2 value of 0.79 and RMSEC of 1.37, validating its accuracy.