Further insights into the assessment of cell cycle phases by FTIR microspectroscopy

Cell Phase Identification in a Three-Dimensional Engineered Tumor Model by Infrared Spectroscopic Imaging

“…The recording of nucleic acid spectral features from cells has been a debated topic and also relates to the ability to detect subtle DNA changes during cell cycle progression. A “black string/dot” hypothesis has been proposed regarding the chromatin folding architecture within the nucleus that results in a lower value than the expected absorbance. ,, Our results are in agreement with more recent studies, which posit that nucleic acid, DNA specifically here, can be treated as a qualitative and semiquantitative biomarker on a single-cell basis to distinguish the cell stage. , To discover the correlation of DNA abundance with respect to DNA duplication and split, flow cytometry is commonly used as a complementary method to support findings from IR measurements. ,, The absorbance of the phosphodiester peak was found to positively correlate with cell cycle progression from G1 to G2/M phases either in hydrated living or dehydrated fixed cells. ,, For better reliability of spectral interpretation of DNA conformation, detailed investigations on various factors, including nucleotide composition, hydration, salt concentration, and counter ion, toward DNA conformation have been undertaken. , These results indicate that with carefully designed experiments and sample preparation protocols, IR spectroscopy has the capability to monitor subtle DNA changes with respect to the cell cycle. To link in vitro studies with physiological conditions, combining customized platforms with IR microscopes could provide more perspectives, even at the single-cell level. , Overall, the extensive understanding of the phosphodiester peak (PO 4 2– ) position and intensity could serve as a promising tool in 3D cultures to provide further information about the dynamics of the nucleus and protein architecture while enabling important relations with clinical studies.…”

“…For instance, fluorescence-activated cell sorting (FACS) can be used to capture temporal snapshots of cellular status, but spatial information is lost. , Tandem methods such as flow cytometry with fluorescence imaging , permit real-time observation of cell phases with the use of machine learning-based classification . While these approaches have enabled new platforms for accurate label-free cell phase identification, examining both cell status and biochemical content from a spectroscopic perspective combined with multivariate analysis has also been an extensive topic. ,,− …”

Contribution of Ribonucleic Acid (RNA) to the Fourier Transform Infrared (FTIR) Spectrum of Eukaryotic Cells

“…Despite its constitutive contribution and its essential part in cell life, RNA has been thus far almost ignored in the analysis of cellular spectra. Since RNA can only assume the A form, the spectral contribution at ∼1240 cm –1 in hydrated cells has been on a first-approximation considered diagnostic of the RNA cellular content, and its contribution to cell cycle progression has already been noted by the authors. , However, to date, there has been no clear attribution of cellular spectral features of RNA. With special regard to its phosphate backbone, little is known on the extent of the overlapping of the asymmetric and symmetric stretching modes with the spectral features of other molecules containing the same moieties, such as DNA, but also phospholipids and phosphorylated proteins.…”

A synchrotron-based infrared microspectroscopy study on the cellular response induced by gold nanoparticles combined with X-ray irradiations on F98 and U87-MG glioma cell lines

“…25 Previous studies have reported similar changes in the DNA region of the infrared spectra due to cell cycle modifications. 36,37 Finally, it is important to note that we clearly observe an increase in the variance of the DNA biochemical content in NP-treated cells with respect to controls (−NP) both at T 0h and T 24h and for both cell lines, as a result of different NP-cell interaction mechanisms.…”