NanoIR Spectroscopy Journal Club

Comparison of AFM-IR, High-Definition FT-IR, and Raman for Subcellular Chemical Imaging of Cholesteryl Esters in Prostate Cancer Cells

by Maciej Roman, Tomasz P. Wrobel, Czeslawa Paluszkiewicz, and Wojciech M. Kwiatek

Key Points

  •  Imaged the chemical structure of cholesteryl esters/cholesterol derivatives in heterogenous cancer cells at the subcellular level;
  • Found that results obtained from FT-IR and Raman imaging showed to be comparable;
  • Demonstrated that results achieved by AFM-IR exhibited higher spectral heterogeneity than either high definition FT-IR or Confocal Raman imaging.


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Journal of Biophotonics 13(5):e201960094

In this paper, three vibrational spectroscopy techniques (Photothermal AFM-IR, high definition FT-IR, and Confocal Raman) were applied for subcellular chemical imaging of cholesteryl esters in PC-3 prostate cancer cells. This sample was chosen as it has a well-defined structure and heterogeneous composition. For the first time, the three techniques were applied to study the same sample and systematically compared in terms of image quality, spectral pattern, and chemical information.

The results showed that while all three techniques are useful in chemical imaging of cholesterol derivatives in cancer cells, the AFM-IR study exhibited higher spectral heterogeneity and higher spatial resolution in chemical mapping. AFM-IR spectra showed IR bands characteristic of lipids and proteins coexisting in the measurement area, and relative intensities of the IR bands vary depending on the locations and suggests diverse composition of the PC-3 prostate cancer cell. The spatial resolution of chemical mapping by AFM-IR was also found to be significantly higher (a factor of ~10 improvement for this specific sample) than high-definition FT-IR and confocal Raman. Overall, this study confirms the AFM-IR method as a powerful tool in local chemical imaging of cells at the nanoscale level.



AFM-IR (PTIR), Analysis of cancer tissues, Bioimaging, Confocal raman spectroscopy, Chemical imaging of cells, Vibrational spectroscopic imaging techniques