Raman spectroscopy and atomic force microscopy as tools to evaluate the radiobiological sensitivity of breast cancer cells at different therapeutic doses

Background and purpose: Radiotherapy is widely used as a treatment for patients with breast cancer (BC).In vitro irradiation of BC cells provides a strategy to investigate early cellular and molecular events induced by ionizing radiation.Characterizing structural and membrane responses may identify biomarkers of radiosensitivity, improving understanding of treatment effects and enabling patient specific optimization.In this work, Raman spectroscopy and atomic force microscopy (AFM) were applied in vitro to investigate mechanisms relevant to BC radiotherapy.Materials and methods: Breast cancer cell line MD Anderson-Metastatic Breast-231 (MDA-MB-231) was exposed to doses of 2, 4, and 10 Gy.Non-irradiated BC cells were used as control samples.Samples were incubated at 37 C, 5% carbon dioxide (CO 2 ), and analyzed at 0, 24, and 48 h post-irradiation using AFM and Raman spectroscopy to detect morphological and biochemical changes.Results: Raman spectroscopy showed significantly increased intensities at 1250, 1455, and 1670 cm -1 at 24 h, followed by decreases at 48 h (4-10 Gy).Atomic force microscopy showed reduced membrane roughness at 0 h from 34.0 3.4 nm in controls to 23.6 2.9 nm at 10 Gy, and from 39.50 6.05 nm to 26.86 5.44 nm at 48 h.The MTT (3-(4,5dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay showed reduced viability at 48 h: 84.0% (2 Gy), 81.5% (4 Gy), and 80.3% (10 Gy).Conclusions: Raman spectroscopy and AFM demonstrate the capability to detect early radiation-induced chemical and surface alterations, suggesting potential utility for identifying biomarkers of radiotherapeutic response in breast cancer cells.