Optimization of Sample Preparation Using Glass Slides for Spectral Pathology.

Area of Science:

• Biomedical Engineering
• Spectroscopy
• Pathology

Background:

• Fourier transform infrared (FT-IR) microspectroscopy is a powerful technique for molecular analysis.
• Clinical translation of FT-IR microspectroscopy in pathology requires integration with standard practices, particularly sample preparation.
• Previous work demonstrated FT-IR spectra acquisition from cells on glass substrates, moving the technique closer to clinical application.

Purpose of the Study:

• To investigate sample preparation methods for FT-IR microspectroscopy of lung cancer cells on glass coverslips.
• To assess the feasibility of differentiating two types of lung cancer cells using FT-IR microspectroscopy with standard pathology sample preparation techniques.
• To optimize fixation and preparation methods for FT-IR spectral data quality.

Main Methods:

• Two common pathology sample preparation methods, cytospin and smear, were employed.
• Cells were fixed using methanol (pathology-used) or formalin (spectroscopy-used).
• FT-IR spectra were acquired from cells on thin glass coverslips, focusing on lipid and fingerprint regions.

Main Results:

• Methanol fixation led to lipid removal, decreasing peak intensity at 2850 cm⁻¹ and 2920 cm⁻¹.
• Despite fixation differences, FT-IR successfully differentiated between two lung cancer cell types using spectral data from the lipid and fingerprint regions (1800–1350 cm⁻¹).
• Formalin-fixed cytospin samples were identified as preferable for FT-IR microspectroscopy on thin coverslips.

Conclusions:

• Sample preparation techniques like cytospin and smear, combined with appropriate fixation, enable FT-IR microspectroscopy for lung cancer cell identification.
• FT-IR microspectroscopy, when applied to cells on glass coverslips, offers a viable method for distinguishing between different lung cancer cell types.
• Formalin-fixed cytospin samples are recommended for future clinical applications of FT-IR microspectroscopy in pathology.