| ATR-FTIR bands (cm⁻¹) | 3600 – 3000 (O-H and N-H stretching), 3000 – 2600 (CH2 and CH3 asymmetric and symmetric stretching), 1454 and 1398 (bending vibrations), 1648 (C=O stretching, amide I), 1600 – 1500 (N-H bending and C-N stretching, amide II), 1350 – 1250 (N-H bending and C-N stretching, amide III), 1208 (C-O stretching), 1050 (C-O-C stretching), 1100 – 900 (C-O-H bending vibrations), 900 – 1200 (phosphate stretching vibrations), around 949 or higher (asymmetric P-O-P stretching), 900 – 1300 (P-O bands), 1250 – 900 (polysaccharidic compounds, carbohydrates, and stretching vibration of the nucleic acid backbone), around 2924 – 2854 and 1454 – 1398 (lipid components), 1240 and 1080 (symmetric and asymmetric stretching vibrational modes of phosphodiester groups), 1040 (polysaccharides vibrational modes) |
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| ATR-FTIR, Osi-resistant compared with parental whole cells | significant intensity increase in ester-related vibrations at ~1736–1720 cm⁻¹ |
| ATR-FTIR | protein bands were detectable in all samples except the LMW fraction, where their contribution was negligible; protein bands were the dominant absorptions in whole-cell and pellet fractions |
| ATR-FTIR PCA, whole cells | PC1 83.6 %; PC2 8.7 %; parental cells were predominantly positioned toward the negative end of PC1 and PC2, while OsiR and ORH cells were grouped toward the positive end |
Beatrice Campanella, Giorgia Maroni, Eva Cabrera Cabrera San Millan, Raffaella Mercatelli, Massimo Onor, Lorenzo Birindelli, Edoardo Benedetti, Elena Levantini, Emilia Bramanti. “ATR-FTIR spectroscopy and chemometric analysis to characterize drug-responsive and drug-resistant human non-small cell lung cancer cells.” ChemRxiv (). https://doi.org/10.26434/chemrxiv.15007468/v1
| ATR-FTIR bands (cm⁻¹) | ~1450, 1410, 1330, 1238, 1210, 1110, 1040, 994, 924, and 850 |
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| ATR-FTIR PCA score plots | clear separation of P and OsiR cells within each fraction |
| ATR-FTIR bands (cm⁻¹) | 964 (detectable only in pellet fractions; may reflect C-C backbone vibrations of ultra-short DNA fragments undergoing A-to-B conformational transitions) |
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| ATR-FTIR PCA score plots | clear separation of P and OsiR cells |
| ATR-FTIR PCA loading variables (cm⁻¹) | 3308, 2954, 2922, 1736, 1720, and 1658; 2922 assigned to CH2 and CH3 stretching vibrations of lipid structures, 1736 to C=O stretching vibrations of aldehydes, 1720 to C=O stretching vibrations of carboxylic acids, and 1658 to Amide I |
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| ATR-FTIR PCA loading bands (cm⁻¹) | 1618, 1510, 1438, 1384, 1216, 1058, and 1046; 1438 and 1384 assigned to CH2 and CH3 bending modes, and 1216, 1058, and 1046 mainly related to C–O bond vibrations |
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