Processing ThinPrep cervical cytological samples for Raman spectroscopic analysis

Raman microspectroscopy has been proven to be a promising technique for diagnosis and early detection of pathologies. The data collected delivers a chemical fingerprint allowing the identification of specific biomarkers indicating the presence of abnormalities. Label free, fast and cost effective, Raman spectroscopy has already been proposed as the new generation of diagnostic tool with a strong potential but has not emerged in the medical field as yet. Notably, it is crucial to improve and adapt the protocols used to reach suitable reproducibility for screening large cohorts of patients. In this study, it is demonstrated that the variability existing in the data sets collected can be limiting. Notably, when working on cervical ThinPrep samples, the presence of blood residue can be detected by Raman spectroscopy swamping the cellular signal. However, combining a washing of the slides using H2O2 and alcohol (70% ethanol and 100% Industrial Methylated Spirits), the blood features are removed from the data without altering either the cell morphology or the spectral features. Ultimately, this work demonstrates the improved potential of Raman spectroscopy for ThinPrep analysis based on improved protocols for sample preparation. Therefore, the screening of cervical cells for the detection of abnormalities and identification of patients with Cervical Intraepithelial Neoplasia (CIN) is achievable.