School of Pharmacy and Bioengineering, Guy Hilton Research Centre, Keele University, Stoke-on-Trent, UK.
Department of Chemistry, Loughborough University, Leicestershire, UK.
Appl Spectrosc. 2021 Mar;75(3):343-350. doi: 10.1177/0003702820945748. Epub 2020 Oct 14.
The clinical translation of Fourier transform infrared (FT-IR) microspectroscopy in pathology will require bringing this technique as close as possible to standard practice in pathology departments. An important step is sample preparation for both FT-IR microspectroscopy and pathology. This should entail minimal disruption of standard clinical practice while achieving good quality FT-IR spectral data. In fact, the recently described possibility of obtaining FT-IR spectra of cells placed on glass substrates brings FT-IR microspectroscopy closer to a clinical application. We have now furthered this work in order to identify two different types of lung cancer cells placed on glass coverslips. Two types of sample preparation which are widely used in pathology, cytospin and smear, have been used. Samples were fixed with either methanol, used in pathology, or formalin (4% paraformaldehyde) used widely in spectroscopy. Fixation with methanol (alcohol-based fixative) removed lipids from cells causing a decrease in intensity of the peaks at 2850 cm and 2920 cm. Nevertheless, we show for the first time that using either type of sample preparation and fixation on thin glass coverslips allowed to differentiate between two different types of lung cancer cells using either the lipid region or the fingerprint region ranging from 1800 cm to 1350 cm. We believe that formalin-fixed cytospin samples would be preferred to study cells on thin coverslips using FT-IR microspectroscopy. This work presents a clear indication for future advances in clinical assessment of samples within pathology units to gain a deeper understanding of cells/tissues under investigation.
傅里叶变换红外（FT-IR）微光谱在病理学中的临床转化将需要使该技术尽可能接近病理学部门的标准实践。一个重要的步骤是为 FT-IR 微光谱和病理学准备样本。这应该在不干扰标准临床实践的情况下，同时获得高质量的 FT-IR 光谱数据。事实上，最近描述的在玻璃基质上获得细胞的 FT-IR 光谱的可能性使 FT-IR 微光谱更接近临床应用。为了鉴定放置在玻璃盖玻片上的两种不同类型的肺癌细胞，我们进一步开展了这项工作。我们使用了两种在病理学中广泛使用的样本制备方法，即细胞离心涂片法和涂片法。样本用甲醇（病理学中使用的）或广泛用于光谱学的甲醛（4%多聚甲醛）固定。甲醇固定（基于酒精的固定剂）会从细胞中去除脂质，导致 2850 cm 和 2920 cm 处峰的强度降低。然而，我们首次表明，使用任何一种样本制备类型和在薄玻璃盖玻片上的固定，可以区分两种不同类型的肺癌细胞，无论是使用脂质区域还是指纹区域（1800 cm 至 1350 cm）。我们认为，使用福尔马林固定的细胞离心涂片样本，将优先用于使用 FT-IR 微光谱研究薄盖玻片上的细胞。这项工作为未来在病理学单位内对样本进行临床评估以更深入地了解所研究的细胞/组织提供了明确的指示。
