Raman spectroscopy: techniques and applications in the life sciences

Abstract

Raman spectroscopy is an increasingly popular technique in many areas including biology and medicine.It is based on Raman scattering, a phenomenon in which incident photons lose or gain energy via interactions with vibrating molecules in a sample. These energy shifts can be used to obtain information regarding molecular composition of the sample with very high accuracy. Applications of Raman spectroscopy in the life sciences have included quantification of biomolecules, hyperspectral molecular imaging of cells and tissue, medical diagnosis, and others. This review briefly presents the physical origin of Raman scattering explaining the key classical and quantum mechanical concepts. Variations of the Raman effect will also be considered, including resonance, coherent, and enhanced Raman scattering. We discuss the molecular origins of prominent bands often found in the Raman spectra of biological samples. Finally, we examine several variations of Raman spectroscopy techniques in practice, looking at their applications, strengths, and challenges. This review is intended to be a starting resource for scientists new to Raman spectroscopy, providing theoretical background and practical examples as the foundation for further study and exploration.

Visualizing the interaction of Acanthamoeba castellanii with human retinal epithelial cells by spontaneous Raman and CARS imaging

“…Raman bands were selected to map the distribution of lipids and proteins (1449 cm −1 ), nucleic acids (786 cm −1 ), L‐Phe (1004 cm −1 ), and L‐Phe(D8; 960 cm −1 ), as shown (Figure ). The results show that Raman spectra of A. castellanii consist of bands typically assigned to lipids, proteins, and nucleic acids, similar to other cell types . The most intense bands can be assigned to molecular vibrations of lipid molecules, such as the C═C stretching 1660 cm −1 , CH 2 deformation 1449 cm −1 , CH 2 twisting 1303 cm −1 , ═C–H deformations 1260 cm −1 , symmetric stretching of N(CH 3 ) 3 of choline group 719 cm −1 .…”

“…The results show that Raman spectra of A. castellanii consist of bands typically assigned to lipids, proteins, and nucleic acids, similar to other cell types. [14,15] The most intense bands can be assigned to molecular vibrations of lipid molecules, such as the C═C stretching 1660 cm −1 , CH 2 deformation 1449 cm −1 , CH 2 twisting 1303 cm −1 , ═C-H deformations 1260 cm −1 , symmetric stretching of N(CH 3 ) 3 of choline group 719 cm −1 . Raman bands corresponding to vibrational modes of the sugar-phosphate backbone in nucleic acids were identified at 788 cm −1 (O-P-O bonds) and 1098 cm −1 (PO 2 − ).…”

“…Spontaneous Raman micro‐spectroscopy (RMS) provides detailed molecular analysis of individual cells with micrometric spatial resolution . With the exception of Plasmodium falciparum , reports of RMS studies of protozoan parasites have been limited.…”

“…Spontaneous Raman micro-spectroscopy (RMS) provides detailed molecular analysis of individual cells with micrometric spatial resolution. [14][15][16][17][18] With the exception of Plasmodium falciparum, [19][20][21] reports of RMS studies of protozoan parasites have been limited. Selective scanning RMS imaging was used to detect Neospora caninum tachyzoites colonizing human brain microvascular-endothelial cells.…”

Potential of short-wave infrared spectroscopy for quantitative depth profiling of stratum corneum lipids and water in dermatology

“…Confocal Raman microspectroscopy has been successfully used for several dermatological applications. With further developments for reducing the cost, CRS has the potential to enter the mainstream of clinical and dermatological practice with even wider range of applications [39][40][41][42].…”