Advances and Challenges in Raman and Surface-Enhanced Raman Spectroscopy for Biological Systems

Raman spectroscopy is a potent, non-destructive analytical method that exhibits molecular-level insights through the inelastic scattering of light. Due to its chemical specificity and minimal sample preparation needs, Raman spectroscopy has been widely utilized in materials science, chemistry, and biomedical research. Notwithstanding these benefits, the extensive utilization of Raman spectroscopy is constrained by various inherent and experimental obstacles, such as low scattering efficiency, fluorescence background interference, laser-induced thermal effects on samples, and inadequate signal reproducibility, especially in intricate biological and aqueous environments. This review provides a concise summary of the fundamental principles of Raman scattering, with a focus on Rayleigh, Stokes, and anti-Stokes processes. It subsequently discusses Raman activity in relation to molecular polarizability. The principal applications of Raman spectroscopy in characterizing proteins, nucleic acids, and lipids are emphasized to illustrate its significance in biological systems. Additionally, significant challenges related to Raman spectral acquisition and interpretation are examined, alongside contemporary strategies to address these limitations, including near-infrared excitation, confocal Raman microscopy, and surface-enhanced Raman spectroscopy (SERS). This review aims to provide researchers with a fundamental understanding of Raman spectroscopy, while also presenting practical considerations and innovative solutions for improving spectral quality and analytical reliability.