Label-free detection of the cytotoxicity effect of cisplatin in human leukemic cells using Raman spectroscopy in conjunction with multivariate analysis†

The single-cell Raman spectra of human leukemic Jurkat cells can be obtained by confocal microscopy Raman spectroscopy, including cell groups treated with different doses of cisplatin (0, 3.5, 7, 10.5 and 14 μmol L⁻¹) for 24 hours and those treated with 10.5 μmol L⁻¹ cisplatin for different times (0, 6, 12, 24 and 36 hours). The structure and amount of protein, nucleic acid and other major molecules from different cell groups show special changes in the percentage of biochemical constituents. Compared with the control group, the two protein Raman bands (1449 and 1659 cm⁻¹) and two DNA bands (1303 and 1338 cm⁻¹) in the treatment groups decrease in intensity with the increase of the drug dose and treatment time of cisplatin. Partial least squares combined with support vector machines was used to develop diagnostic algorithms for distinguishing between control and treatment groups. The support vector machines for classification between the control group (0 μmol L⁻¹) and cell groups treated with 10.5 and 14 μmol L⁻¹ cisplatin for 24 hours have achieved good diagnostic results with a high sensitivity of 100%, specificity of 100% and accuracy of 100%, respectively, indicating that 10.5 μmol L⁻¹ can be used as an appropriate therapeutic dose. Using the same method, the diagnostic sensitivity, specificity and accuracy between the control group (0 hours) and cell groups treated with 10.5 μmol L⁻¹ cisplatin for 24 and 36 hours are all 100%, showing that 24 hours can be used as an appropriate therapeutic time. These results showed that Raman spectroscopy in conjunction with multivariate statistical analysis could be a useful tool for evaluating the cytotoxicity induced by cisplatin in human leukemic cells.