Surface-Enhanced Raman Spectroscopy for the Characterization of the Antibacterial Properties of Imidazole Derivatives against Bacillus subtilis with Principal Component Analysis and Partial Least Squares–Discriminant Analysis

Abstract

Surface enhanced Raman spectroscopy (SERS) was used to determine the biochemical changes induced during the antibacterial activity of the in house synthesized imidazole derivatives in comparison to the commercially available pharmaceutical tinidazole. The antibacterial activity was assessed against Bacillus subtilis using various concentrations of antibacterial agents for this purpose. SERS detected significant changes in the bacterial cells following the application of both drugs, confirming the potential of this approach for analyzing the antibacterial activities of drug candidates. The SERS spectral features changed consistently with the increased antibiotic concentration at 548, 713, 730, 807, 858, 951, 958, 1004, 1028, 1110, 1128, 1242, 1280, 1320, 1398, 1418, 1453, 1567, and 1590 cm⁻¹. Principal component analysis (PCA) and partial least squares–discriminant analysis (PLS-DA) were demonstrated to be useful for comparing the antibacterial actions of these imidazole derivatives. The sensitivity and specificity of this model were 97% and 95.7% respectively.

Keywords:

• Surface-enhanced Raman spectroscopy
• antibacterial activity
• antibiotic
• imidazole derivatives
• principal component analysis
• partial least squares–discriminant analysis